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Bassoon

The bassoon is a musical instrument in the woodwind family, which plays in the tenor and bass ranges. It is composed of six pieces, and is usually made of wood. It is known for its distinctive tone color, wide range, versatility, and virtuosity. It is a non-transposing instrument and typically its music is written in the bass and tenor clefs, and sometimes in the treble. There are two forms of modern bassoon: the Buffet (or French) and Heckel (or German) systems. It is typically played while sitting using a seat strap, but can be played while standing if the player has a harness to hold the instrument. Sound is produced by rolling both lips over the reed and blowing direct air pressure to cause the reed to vibrate. Its fingering system can be quite complex when compared to those of other instruments. Appearing in its modern form in the 19th century, the bassoon figures prominently in orchestral, concert band, and chamber music literature, and is occasionally heard in pop, rock, and jazz settings as well. One who plays a bassoon is called a bassoonist.

Etymology
The word bassoon comes from French basson and from Italian bassone (basso with the augmentative suffix -one). However, the Italian name for the same instrument is fagotto, in Spanish, Dutch, Danish, Czech, Polish, Serbo-Croatian and Romanian it is fagot, and in German Fagott. Fagot is an Old French word meaning a bundle of sticks. The dulcian came to be known as fagotto in Italy. However, the usual etymology that equates fagotto with "bundle of sticks" is somewhat misleading, as the latter term did not come into general use until later. However an early English variation, "faget", was used as early as 1450 to refer to firewood, which is 100 years before the earliest recorded use of the dulcian (1550). Further citation is needed to prove the lack of relation between the meaning "bundle of sticks" and "fagotto" (Italian) or variants. Some think that it may resemble the Roman fasces, a standard of bound sticks with an axe. A further discrepancy lies in the fact that the dulcian was carved out of a single block of wood—in other words, a single "stick" and not a bundle.

Range
Bassoon Range.svg of a bassoon (A1) B♭1–E5 (A♭5)

]] The range of the bassoon begins at B♭1 (the first one below the bass staff) and extends upward over three octaves, roughly to the G above the treble staff (G5). However, most writing for bassoon rarely calls for notes above C5 or D5; even Stravinsky's opening solo in The Rite of Spring only ascends to D5. Notes higher than this are possible, but seldom written, as they are difficult to produce (often requiring specific reed design features to ensure reliability), and at any rate are quite homogeneous in timbre to the same pitches on cor anglais, which can produce them with relative ease. French bassoon has greater facility in the extreme high register, and so repertoire written for it is somewhat likelier to include very high notes, although repertoire for French system can be executed on German system without alterations and vice versa.

The extensive high register of the bassoon and its frequent role as a lyric tenor have meant that tenor clef is very commonly employed in its literature after the Baroque, partly to avoid excessive ledger lines, and, beginning in the 20th century, treble clef is also seen for similar reasons.

Like other woodwind instruments, the lowest note is fixed, but A1 is possible with a special extension to the instrument—see "Extended techniques" below.

Although the primary tone hole pitches are a pitched perfect 5th lower than other non-transposing Western woodwinds (effectively an octave beneath English horn) the bassoon is non-transposing, meaning that notes sounded match the written pitch.

Construction

The bassoon disassembles into six main pieces, including the reed. The bell (6), extending upward; the bass joint (or long joint) (5) , connecting the bell and the boot; the boot (or butt) (4) , at the bottom of the instrument and folding over on itself; the wing joint (or tenor joint) (3) , which extends from boot to bocal; and the bocal (or crook) (2) , a crooked metal tube that attaches the wing joint to a reed (1).

Structure
The bore of the bassoon is conical, like that of the oboe and the saxophone, and the two adjoining bores of the boot joint are connected at the bottom of the instrument with a U-shaped metal connector. Both bore and tone holes are precision-machined, and each instrument is finished by hand for proper tuning. The walls of the bassoon are thicker at various points along the bore; here, the tone holes are drilled at an angle to the axis of the bore, which reduces the distance between the holes on the exterior. This ensures coverage by the fingers of the average adult hand. Playing is facilitated by closing the distance between the widely spaced holes with a complex system of key work, which extends throughout nearly the entire length of the instrument. The overall height of the bassoon stretches to 1.34 m tall, but the total sounding length is 2.54 m considering that the tube is doubled back on itself. There are also short-reach bassoons made for the benefit of young or petite players.

Materials
A modern beginner's bassoon is generally made of maple, with medium-hardness types such as sycamore maple and sugar maple preferred. Less-expensive models are also made of materials such as polypropylene and ebonite, primarily for student and outdoor use. Metal bassoons were made in the past but have not been produced by any major manufacturer since 1889.

Double Reeds
The art of reed-making has been practiced for several hundred years, some of the earliest known reeds having been made for the dulcian, a predecessor of the bassoon. Current methods of reed-making consist of a set of basic methods; however, individual bassoonists' playing styles vary greatly and thus require that reeds be customized to best suit their respective bassoonist. Advanced players usually make their own reeds to this end. With regards to commercially made reeds, many companies and individuals offer pre-made reeds for sale, but players often find that such reeds still require adjustments to suit their particular playing style.

Modern bassoon reeds, made of Arundo donax cane, are often made by the players themselves, although beginner bassoonists tend to buy their reeds from professional reed makers or use reeds made by their teachers. Reeds begin with a length of tube cane that is split into three or four pieces using a tool called a cane splitter. The cane is then trimmed and gouged to the desired thickness, leaving the bark attached. After soaking, the gouged cane is cut to the proper shape and milled to the desired thickness, or profiled, by removing material from the bark side. This can be done by hand with a file; more frequently it is done with a machine or tool designed for the purpose. After the profiled cane has soaked once again it is folded over in the middle. Prior to soaking, the reed maker will have lightly scored the bark with parallel lines with a knife; this ensures that the cane will assume a cylindrical shape during the forming stage.

On the bark portion, the reed maker binds on one, two, or three coils or loops of brass wire to aid in the final forming process. The exact placement of these loops can vary somewhat depending on the reed maker. The bound reed blank is then wrapped with thick cotton or linen thread to protect it, and a conical steel mandrel (which sometimes has been heated in a flame) is quickly inserted in between the blades. Using a special pair of pliers, the reed maker presses down the cane, making it conform to the shape of the mandrel. (The steam generated by the heated mandrel causes the cane to permanently assume the shape of the mandrel.) The upper portion of the cavity thus created is called the "throat", and its shape has an influence on the final playing characteristics of the reed. The lower, mostly cylindrical portion will be reamed out with a special tool called a reamer, allowing the reed to fit on the bocal.

After the reed has dried, the wires are tightened around the reed, which has shrunk after drying, or replaced completely. The lower part is sealed (a nitrocellulose-based cement such as Duco may be used) and then wrapped with thread to ensure both that no air leaks out through the bottom of the reed and that the reed maintains its shape. The wrapping itself is often sealed with Duco or clear nail varnish (polish). Electrical tape can also be used as a wrapping for amateur reed makers. The bulge in the wrapping is sometimes referred to as the "Turk's head"—it serves as a convenient handle when inserting the reed on the bocal. Alternatively, hot glue, epoxy, or heat shrink wrap may be used to seal the tube of the reed. The thread wrapping (commonly known as a "Turban" due to the criss-crossing fabric) is still more common in commercially sold reeds.

To finish the reed, the end of the reed blank, originally at the center of the unfolded piece of cane, is cut off, creating an opening. The blades above the first wire are now roughly 27 - 30 mm long. For the reed to play, a slight bevel must be created at the tip with a knife, although there is also a machine that can perform this function. Other adjustments with the reed knife may be necessary, depending on the hardness, the profile of the cane, and the requirements of the player. The reed opening may also need to be adjusted by squeezing either the first or second wire with the pliers. Additional material may be removed from the sides (the "channels") or tip to balance the reed. Additionally, if the "e" in the bass clef staff is sagging in pitch, it may be necessary to "clip" the reed by removing 1 - 2 mm from its length using a pair of very sharp scissors or the equivalent.

Origin
Music historians generally consider the dulcian to be the forerunner of the modern bassoon, as the two instruments share many characteristics: a double reed fitted to a metal crook, obliquely drilled tone holes and a conical bore that doubles back on itself. The origins of the dulcian are obscure, but by the mid-16th century it was available in as many as eight different sizes, from soprano to great bass. A full consort of dulcians was a rarity; its primary function seems to have been to provide the bass in the typical wind band of the time, either loud (shawms) or soft (recorders), indicating a remarkable ability to vary dynamics to suit the need. Otherwise, dulcian technique was rather primitive, with eight finger holes and two keys, indicating that it could play in only a limited number of key signatures.

Circumstantial evidence indicates that the baroque bassoon was a newly invented instrument, rather than a simple modification of the old dulcian. The dulcian was not immediately supplanted, but continued to be used well into the 18th century by Bach and others; and, presumably for reasons of interchangeability, repertoire from this time is very unlikely to go beyond the smaller compass of the dulcian. The man most likely responsible for developing the true bassoon was Martin Hotteterre (d.1712), who may also have invented the three-piece flûte traversière (transverse flute) and the hautbois (baroque oboe). Some historians believe that sometime in the 1650s, Hotteterre conceived the bassoon in four sections (bell, bass joint, boot and wing joint), an arrangement that allowed greater accuracy in machining the bore compared to the one-piece dulcian. He also extended the compass down to B♭ by adding two keys. An alternate view maintains Hotteterre was one of several craftsmen responsible for the development of the early bassoon. These may have included additional members of the Hotteterre family, as well as other French makers active around the same time. No original French bassoon from this period survives, but if it did, it would most likely resemble the earliest extant bassoons of Johann Christoph Denner and Richard Haka from the 1680s. Sometime around 1700, a fourth key (G♯) was added, and it was for this type of instrument that composers such as Antonio Vivaldi, Bach, and Georg Philipp Telemann wrote their demanding music. A fifth key, for the low E♭, was added during the first half of the 18th century. Notable makers of the 4-key and 5-key baroque bassoon include J.H. Eichentopf (c. 1678–1769), J. Poerschmann (1680–1757), Thomas Stanesby, Jr. (1668–1734), G.H. Scherer (1703–1778), and Prudent Thieriot (1732–1786).

Modern configuration
Increasing demands on capabilities of instruments and players in the 19th century—particularly larger concert halls requiring greater volume and the rise of virtuoso composer-performers—spurred further refinement. Increased sophistication, both in manufacturing techniques and acoustical knowledge, made possible great improvements in the instrument's playability.

The modern bassoon exists in two distinct primary forms, the Buffet (or "French") system and the Heckel ("German") system. Most of the world plays the Heckel system, while the Buffet system is primarily played in France, Belgium, and parts of Latin America. A number of other types of bassoons have been constructed by various instrument makers, such as the rare Galandronome. Owing to the ubiquity of the Heckel system in English-speaking countries, references in English to the contemporary bassoon always mean the Heckel system, with the Buffet system being explicitly qualified where it appears.

Heckel (German) system
The design of the modern bassoon owes a great deal to the performer, teacher, and composer Carl Almenräder. Assisted by the German acoustic researcher Gottfried Weber, he developed the 17-key bassoon with a range spanning four octaves. Almenräder's improvements to the bassoon began with an 1823 treatise describing ways of improving intonation, response, and technical ease of playing by augmenting and rearranging the keywork. Subsequent articles further developed his ideas. His employment at Schott gave him the freedom to construct and test instruments according to these new designs, and he published the results in Caecilia, Schott's house journal. Almenräder continued publishing and building instruments until his death in 1846, and Ludwig van Beethoven himself requested one of the newly made instruments after hearing of the papers. In 1831, Almenräder left Schott to start his own factory with a partner, Johann Adam Heckel.

Heckel and two generations of descendants continued to refine the bassoon, and their instruments became the standard, with other makers following. Because of their superior singing tone quality (an improvement upon one of the main drawbacks of the Almenräder instruments), the Heckel instruments competed for prominence with the reformed Wiener system, a Boehm-style bassoon, and a completely keyed instrument devised by Charles-Joseph Sax, father of Adolphe Sax. F.W. Kruspe implemented a latecomer attempt in 1893 to reform the fingering system, but it failed to catch on. Other attempts to improve the instrument included a 24-keyed model and a single-reed mouthpiece, but both these had adverse effects on tone and were abandoned.

Coming into the 20th century, the Heckel-style German model of bassoon dominated the field. Heckel himself had made over 1,100 instruments by the turn of the 20th century (serial numbers begin at 3,000), and the British makers' instruments were no longer desirable for the changing pitch requirements of the symphony orchestra, remaining primarily in military band use.

Except for a brief 1940s wartime conversion to ball bearing manufacture, the Heckel concern has produced instruments continuously to the present day. Heckel bassoons are considered by many to be the best, although a range of Heckel-style instruments is available from several other manufacturers, all with slightly different playing characteristics.

Because its mechanism is primitive compared to most modern woodwinds, makers have occasionally attempted to "reinvent" the bassoon. In the 1960s, Giles Brindley began to develop what he called the "logical bassoon", which aimed to improve intonation and evenness of tone through use of an electrically activated mechanism, making possible key combinations too complex for the human hand to manage. Brindley's logical bassoon was never marketed.

Buffet (French) system
The Buffet system bassoon achieved its basic acoustical properties somewhat earlier than the Heckel. Thereafter, it continued to develop in a more conservative manner. While the early history of the Heckel bassoon included a complete overhaul of the instrument in both acoustics and key work, the development of the Buffet system consisted primarily of incremental improvements to the key work. This minimalist approach of the Buffet deprived it of improved consistency of intonation, ease of operation, and increased power, which is found in Heckel bassoons, but the Buffet is considered by some to have a more vocal and expressive quality. The conductor John Foulds lamented in 1934 the dominance of the Heckel-style bassoon, considering them too homogeneous in sound with the horn. The modern Buffet system has 22 keys with its range being the same as the Heckel; although Buffet instruments have greater facility in the upper registers, reaching E5 and F5 with far greater ease and less air resistance.

Compared to the Heckel bassoon, Buffet system bassoons have a narrower bore and simpler mechanism, requiring different, and often more complex fingerings for many notes. Switching between Heckel and Buffet, or vice versa, requires extensive retraining. French woodwind instruments' tone in general exhibits a certain amount of "edge", with more of a vocal quality than is usual elsewhere, and the Buffet bassoon is no exception. This sound has been utilised effectively in writing for Buffet bassoon, but is less inclined to blend than the tone of the Heckel bassoon. As with all bassoons, the tone varies considerably, depending on individual instrument, reed, and performer. In the hands of a lesser player, the Heckel bassoon can sound flat and woody, but good players succeed in producing a vibrant, singing tone. Conversely, a poorly played Buffet can sound buzzy and nasal, but good players succeed in producing a warm, expressive sound.

Though the United Kingdom once favored the French system, Buffet-system instruments are no longer made there and the last prominent British player of the French system retired in the 1980s. However, with continued use in some regions and its distinctive tone, the Buffet continues to have a place in modern bassoon playing, particularly in France, where it originated. Buffet-model bassoons are currently made in Paris by Buffet Crampon and the atelier Ducasse (Romainville, France). The Selmer Company stopped fabrication of French system bassoons around the year 2012. Some players, for example the late Gerald Corey in Canada, have learned to play both types and will alternate between them depending on the repertoire.

Pre-1760
Prior to 1760, the early ancestor of the bassoon was the dulcian. It was used to reinforce the bass line in wind ensembles called consorts. However, its use in concert orchestras was sporadic until the late 17th century when double reeds began to make their way into standard instrumentation. Increasing use of the dulcian as a basso continuo instrument meant that it began to be included in opera orchestras, in works such as those by Reinhard Keiser and Jean-Baptiste Lully. Meanwhile, as the dulcian advanced technologically and was able to achieve more virtuosity, composers such as Joseph Bodin de Boismortier, Johann Ernst Galliard, Johann Friedrich Fasch and Georg Philipp Telemann wrote demanding solo and ensemble music for the instrument. Antonio Vivaldi brought it to prominence by featuring it in thirty-nine concerti.

c. 1760–1830
While the bassoon was still often used to give clarity to the bassline due to its sonorous low register, the capabilities of wind instruments grew as technology advanced during the Classical era. This allowed the instrument to play in more keys than the dulcian. Joseph Haydn took advantage of this in his Symphony No. 45 ("Farewell Symphony"), in which the bassoon plays in F-sharp minor. Following with these advances, composers also began to exploit the bassoon for its unique color, flexibility, and virtuosic ability, rather than for its perfunctory ability to double the bass line. Those who did this include Ludwig van Beethoven in his three Duos for Clarinet and Bassoon (WoO 27) for clarinet and bassoon and Niccolo Paganini in his duets for violin and bassoon. In his Bassoon Concerto in B-flat major, K. 191, W. A. Mozart utilized all aspects of the bassoon's expressiveness with its contrasts in register, staccato playing, and expressive sound, and was especially noted for its singing quality in the second movement. This concerto is often considered one of the most important works in all of the bassoon's repertoire, even today.

The bassoon's similarity to the human voice, in addition to its newfound virtuosic ability, was another quality many composers took advantage of during the classical era. After 1730, the German bassoon's range expended up to B♭4, and much higher with the French instrument. Technological advances also caused the bassoon's tenor register sound to become more resonant, and playing in this register grew in popularity, especially in the Austro-Germanic musical world. Pedagogues such as Josef Frohlich instructed students to practice scales, thirds, and fourths as vocal students would. In 1829, he wrote that the bassoon was capable of expressing "the worthy, the virile, the solemn, the great, the sublime, composure, mildness, intimacy, emotion, longing, heartfulness, reverence, and soulful ardour." In G.F. Brandt's performance of Carl Maria von Weber's Concerto for Bassoon in F Major, Op. 75 (J. 127) it was also likened to the human voice. In France, Pierre Cugnier described the bassoon's role as encompassing not only the bass part, but also to accompany the voice and harp, play in pairs with clarinets and horns in Harmonie, and to play in "nearly all types of music," including concerti, which were much more common than the sonatas of the previous era. Both Cugnier and Étienne Ozi emphasized the importance of the bassoon's similarity to the singing voice.

The role of the bassoon in the orchestra varied depending on the country. In the Viennese orchestra the instrument offered a three-dimensional sound to the ensemble by doubling other instruments such as violins, as heard in Mozart's overture to The Marriage of Figaro, K 492. where it plays a rather technical part alongside the strings. He also wrote for the bassoon to change its timbre depending on which instrument it was paired with; warmer with clarinets, hollow with flutes, and dark and dignified with violins. In Germany and Scandinavian countries, orchestras typically featured only two bassoons. But in France, orchestras increased the number to four in the latter half of the nineteenth century. In England, the bassoonist's role varied depending on the ensemble. Johann Christian Bach wrote two concertos for solo bassoon, and it also appeared in more supportive roles such as accompanying church choirs after the Puritan revolution destroyed most church organs. In the American colonies, the bassoon was typically seen in a chamber setting. After the Revolutionary War, bassoonists were found in wind bands that gave public performances. By 1800, there was at least one bassoon in the United States Marine Band. In South America, the bassoon also appeared in small orchestras, bands, and military musique (similar to Harmonie ensembles).

c. 1830–1900
The role of the bassoon during the Romantic era varied between a role as a supportive bass instrument and a role as a virtuosic, expressive, solo instrument. In fact, it was very much considered an instrument that could be used in almost any circumstance. The comparison of the bassoon's sound to the human voice continued on during this time, as much of the pedagogy surrounded emulating this sound. Giuseppe Verdi used the instrument's lyrical, singing voice to evoke emotion in pieces such as his Messa da Requiem. Eugene Jancourt compared the use of vibrato on the bassoon to that of singers, and Luigi Orselli wrote that the bassoon blended well with human voice. He also noted the function of the bassoon in the French orchestra at the time, which served to support the sound of the viola, reinforce staccato sound, and double the bass, clarinet, flute, and oboe. Emphasis also began to be placed on the unique sound of the bassoon's staccato, which might be described as quite short and aggressive, such as in Hector Berlioz's Symphonie fantastique, Op. 14 in the fifth movement. Paul Dukas utilized the staccato to depict the image of two brooms coming to life in The Sorcerer's Apprentice.

It was common for there to be only two bassoons in German orchestras. Austrian and British military bands also only carried two bassoons, and were mainly used for accompaniment and offbeat playing. In France, Hector Berlioz also made it fashionable to use more than two bassoons; he often scored for three or four, and at time wrote for up to eight such as in his l'Impériale.

At this point, composers expected bassoons to be as virtuosic as the other wind instruments, as they often wrote solos challenging the range and technique of the instrument. Examples of this include Nikolai Rimsky-Korsakov's bassoon solo and cadenza following the clarinet in Sheherazade, Op. 35 and in Richard Wagner's Tannhäuser, which required the bassoonist to triple tongue and also play up to the top of its range at an E5. Wagner also used the bassoon for its staccato ability in his work, and often wrote his three bassoon parts in thirds to evoke a darker sound with noticeable tone color. In Modest Mussorgsky's Night on Bald Mountain, the bassoons play fortissimo alongside other bass instruments in order to evoke "the voice of the Devil."

20th and 21st century ensembles
At this point in time, the development of the bassoon slowed. Rather than making large leaps in technological improvements, tiny imperfections in the instrument's function were corrected. The instrument became quite versatile throughout the twentieth century; the instrument was at this point able to play three octaves, a variety of different trills, and maintained stable intonation across all registers and dynamic levels. The pedagogy among bassoonists varied among different countries, and so the overall instrument itself played a variety of roles. As was a common theme in previous eras, the bassoon was valued by composers for its unique voice, and its use rose higher in pitch. A famous example of this is the beginning of Igor Stravinsky's Rite of Spring in which the bassoon plays in its highest register in order to mimic the Russian Dentsivka. Composers also wrote for the bassoon's middle register, such as in Stravinsky's "Berceuse" in The Firebird and Symphony No. 5 in E-flat major, Op. 82 by Jean Sibelius. They also continued to highlight the staccato sound of the bassoon, as heard in Sergei Prokofiev's Humorous Scherzo. In Sergei Prokofiev's Peter and the Wolf, the part of the grandfather is played by the bassoon.

In orchestral settings, most orchestras from the beginning of the twentieth century to the present have three or four bassoonists, with the fourth typically covering contrabassoon as well. Greater emphasis on the use of timbre, vibrato, and phrasing began to appear in bassoon pedagogy, and many followed Marcel Tabuteau's philosophy on musical phrasing. Vibrato began to be used in ensemble playing, depending on the phrasing of the music. The bassoon was, and currently is, expected to be fluent with other woodwinds in terms of virtuosity and technique. Examples of this include the cadenza for bassoons in Maurice Ravel's Rapsodie espagnole and the multi-finger trills used in Stravinsky's Octet. In the twentieth century, the bassoon was less of a concerto soloist, and when it was, the accompanying ensemble was made softer and quieter. In addition, it was no longer used in marching bands, though still existed in concert bands with one or two of them. Orchestral repertoire remained very much the same Austro-Germanic tradition throughout most Western countries. It mostly appeared in solo, chamber, and symphonic settings. By the mid-1900s, broadcasting and recording grew in popularity, allowing for new opportunities for bassoonists, and leading to a slow decline of live performances. Much of the new music for bassoon in the late twentieth and early twenty-first centuries, often included extended techniques and was written for solo or chamber settings. One piece that included extended techniques was Luciano Berio's Sequenza XII, which called for microtonal fingerings, glissandos, and timbral trills. Double and triple tonguing, flutter tonguing, multiphonics, quarter-tones, and singing are all utilized in Bruno Bartolozzi's Concertazioni. There were also a variety of concerti and bassoon and piano pieces written, such as John Williams's Five Sacred Trees and André Previn's Sonata for bassoon and piano. There were also "performance" pieces such as Peter Schickele's Sonata Abassoonata, which required the bassoonist to be both a musician and an actor. The bassoon quartet became prominent at this time, with pieces such as Daniel Dorff's It Takes Four to Tango.

Jazz
The bassoon is infrequently used as a jazz instrument and rarely seen in a jazz ensemble. It first began appearing in the 1920s, when Garvin Bushell began incorporating the bassoon in his performances. Specific calls for its use occurred in Paul Whiteman's group, the unusual octets of Alec Wilder, and a few other session appearances. The next few decades saw the instrument used only sporadically, as symphonic jazz fell out of favor, but the 1960s saw artists such as Yusef Lateef and Chick Corea incorporate bassoon into their recordings. Lateef's diverse and eclectic instrumentation saw the bassoon as a natural addition (see, e.g., The Centaur and the Phoenix (1960) which features bassoon as part of a 6-man horn section, including a few solos) while Corea employed the bassoon in combination with flautist Hubert Laws.

More recently, Illinois Jacquet, Ray Pizzi, Frank Tiberi, and Marshall Allen have both doubled on bassoon in addition to their saxophone performances. Bassoonist Karen Borca, a performer of free jazz, is one of the few jazz musicians to play only bassoon; Michael Rabinowitz, the Spanish bassoonist Javier Abad, and James Lassen, an American resident in Bergen, Norway, are others. Katherine Young plays the bassoon in the ensembles of Anthony Braxton. Lindsay Cooper, Paul Hanson, the Brazilian bassoonist Alexandre Silvério, Trent Jacobs and Daniel Smith are also currently using the bassoon in jazz. French bassoonists Jean-Jacques Decreux and Alexandre Ouzounoff have both recorded jazz, exploiting the flexibility of the Buffet system instrument to good effect.

Popular music
In conjunction with the use of electronic pickups and amplification, the instrument began to be used more somewhat in jazz and rock settings. However, the bassoon is still quite rare as a regular member of rock bands. Several 1960s pop music hits feature the bassoon, including "The Tears of a Clown" by Smokey Robinson and the Miracles (the bassoonist was Charles R. Sirard ), "Jennifer Juniper" by Donovan, "59th Street Bridge Song" by Harpers Bizarre, and the oompah bassoon underlying The New Vaudeville Band's "Winchester Cathedral". From 1974 to 1978, the bassoon was played by Lindsay Cooper in the British avant-garde band Henry Cow. The Leonard Nimoy song "The Ballad of Bilbo Baggins" features the bassoon. In the 1970s it was played, in the British medieval/progressive rock band Gryphon, by Brian Gulland, as well as by the American band Ambrosia, where it was played by drummer Burleigh Drummond. The Belgian Rock in Opposition-band Univers Zero is also known for its use of the bassoon.

More recently, These New Puritans's 2010 album Hidden makes heavy use of the instrument throughout; their principal songwriter, Jack Barnett, claimed repeatedly to be "writing a lot of music for bassoon" in the run-up to its recording. The rock band Better Than Ezra took their name from a passage in Ernest Hemingway's A Moveable Feast in which the author comments that listening to an annoyingly talkative person is still "better than Ezra learning how to play the bassoon", referring to Ezra Pound.

British psychedelic/progressive rock band Knifeworld features the bassoon playing of Chloe Herrington, who also plays for experimental chamber rock orchestra Chrome Hoof.

Fiona Apple featured the bassoon in the opening track of her 2004 album Extraordinary Machine.

In 2016, the bassoon was featured on the album Gang Signs and Prayers by UK "grime" artist Stormzy. Played by UK bassoonist Louise Watson, the bassoon is heard in the tracks "Cold" and "Mr Skeng" as a complement to the electronic synthesizer bass lines typically found in this genre.

Appearance in Television
The Cartoon Network animated series Over the Garden Wall features a bassoon in episode 6 entitled "Lullaby in Frogland", where the main character is encouraged to play the bassoon to impress a group of frogs.

The character Jan Bellows in the Hulu series Only Murders in the Building is a professional bassoonist.

Technique

The bassoon is held diagonally in front of the player, but unlike the flute, oboe and clarinet, it cannot be easily supported by the player's hands alone. Some means of additional support is usually required; the most common ones are a seat strap attached to the base of the boot joint, which is laid across the chair seat prior to sitting down, or a neck strap or shoulder harness attached to the top of the boot joint. Occasionally a spike similar to those used for the cello or the bass clarinet is attached to the bottom of the boot joint and rests on the floor. It is possible to play while standing up if the player uses a neck strap or similar harness, or if the seat strap is tied to the belt. Sometimes a device called a balance hanger is used when playing in a standing position. This is installed between the instrument and the neck strap, and shifts the point of support closer to the center of gravity, adjusting the distribution of weight between the two hands.

The bassoon is played with both hands in a stationary position, the left above the right, with five main finger holes on the front of the instrument (nearest the audience) plus a sixth that is activated by an open-standing key. Five additional keys on the front are controlled by the little fingers of each hand. The back of the instrument (nearest the player) has twelve or more keys to be controlled by the thumbs, the exact number varying depending on model.

To stabilize the right hand, many bassoonists use an adjustable comma-shaped apparatus called a "crutch", or a hand rest, which mounts to the boot joint. The crutch is secured with a thumb screw, which also allows the distance that it protrudes from the bassoon to be adjusted. Players rest the curve of the right hand where the thumb joins the palm against the crutch. The crutch also keeps the right hand from tiring and enables the player to keep the finger pads flat on the finger holes and keys.

An aspect of bassoon technique not found on any other woodwind is called flicking. It involves the left hand thumb momentarily pressing, or "flicking" the high A, C and D keys at the beginning of certain notes in the middle octave to achieve a clean slur from a lower note. This eliminates cracking, or brief multiphonics that happens without the use of this technique. Alternatively, a similar method is called "venting", which requires that the register key be used as part of the full fingering as opposed to being open momentarily at the start of the note. This is sometimes called the "European style"; venting raises the intonation of the notes slightly, and it can be advantageous when tuning to higher frequencies. Some bassoonists flick A and B♭ when tongued, for clarity of articulation, but flicking (or venting) is practically ubiquitous for slurs.

While flicking is used to slur up to higher notes, the whisper key is used for lower notes. From the A♭ right below middle C and lower, the whisper key is pressed with the left thumb and held for the duration of the note. This prevents cracking, as low notes can sometimes crack into a higher octave. Both flicking and using the whisper key is especially important to ensure notes speak properly during slurring between high and low registers.

While bassoons are usually critically tuned at the factory, the player nonetheless has a great degree of flexibility of pitch control through the use of breath support, embouchure, and reed profile. Players can also use alternate fingerings to adjust the pitch of many notes. Similar to other woodwind instruments, the length of the bassoon can be increased to lower pitch or decreased to raise pitch. On the bassoon, this is done preferably by changing the bocal to one of a different length, (lengths are denoted by a number on the bocal, usually starting at 0 for the shortest length, and 3 for the longest, but there are some manufacturers who will use other numbers) but it is possible to push the bocal in or out slightly to grossly adjust the pitch.

Embouchure and sound production
The bassoon embouchure is a very important aspect of producing a full, round, and rich sound on the instrument. The lips are both rolled over the teeth, often with the upper lip further along in an "overbite". The lips provide micromuscular pressure on the entire circumference of the reed, which grossly controls intonation and harmonic excitement, and thus must be constantly modulated with every change of note. How far along the reed the lips are placed affects both tone (with less reed in the mouth making the sound more edged or "reedy", and more reed making it smooth and less projectile) and the way the reed will respond to pressure.

The musculature employed in a bassoon embouchure is primarily around the lips, which pressure the reed into the shapes needed for the desired sound. The jaw is raised or lowered to adjust the oral cavity for better reed control, but the jaw muscles are used much less for upward vertical pressure than in single reeds, only being substantially employed in the very high register. However, double reed students often "bite" the reed with these muscles because the control and tone of the labial and other muscles is still developing, but this generally makes the sound sharp and "choked" as it contracts the aperture of the reed and stifles the vibration of its blades.

Apart from the embouchure proper, students must also develop substantial muscle tone and control in the diaphragm, throat, neck and upper chest, which are all employed to increase and direct air pressure. Air pressure is a very important aspect of the tone, intonation and projection of double reed instruments, affecting these qualities as much, or more than the embouchure does.

Attacking a note on the bassoon with imprecise amounts of muscle or air pressure for the desired pitch will result in poor intonation, cracking or multiphonics, accidentally producing the incorrect partial, or the reed not speaking at all. These problems are compounded by the individual qualities of reeds, which are categorically inconsistent in behaviour for inherent and exherent reasons.

The muscle requirements and variability of reeds mean it takes some time for bassoonists (and oboists) to develop an embouchure that exhibits consistent control across all reeds, dynamics and playing environments.

Modern fingering

The fingering technique of the bassoon varies more between players, by a wide margin, than that of any other orchestral woodwind. The complex mechanism and acoustics mean the bassoon lacks simple fingerings of good sound quality or intonation for some notes (especially in the higher range), but, conversely, there is a great variety of superior, but generally more complicated, fingerings for them. Typically, the simpler fingerings for such notes are used as alternate or trill fingerings, and the bassoonist will use as "full fingering" one or several of the more complex executions possible, for optimal sound quality. The fingerings used are at the discretion of the bassoonist, and, for particular passages, he or she may experiment to find new alternate fingerings that are thus idiomatic to the player.

These elements have resulted in both "full" and alternate fingerings differing extensively between bassoonists, and are further informed by factors such as cultural difference in what sound is sought, how reeds are made, and regional variation in tuning frequencies (necessitating sharper or flatter fingerings). Regional enclaves of bassoonists tend to have some uniformity in technique, but on a global scale, technique differs such that two given bassoonists may share no fingerings for certain notes. Owing to these factors, ubiquitous bassoon technique can only be partially notated.

The left thumb operates nine keys: B♭1, B1, C2, D2, D5, C5 (also B4), two keys when combined create A4, and the whisper key. The whisper key should be held down for notes between and including F2 and G♯3 and certain other notes; it can be omitted, but the pitch will destabilise. Additional notes can be created with the left thumb keys; the D2 and bottom key above the whisper key on the tenor joint (C♯ key) together create both C♯3 and C♯4. The same bottom tenor-joint key is also used, with additional fingering, to create E5 and F5. D5 and C5 together create C♯5. When the two keys on the tenor joint to create A4 are used with slightly altered fingering on the boot joint, B♭4 is created. The whisper key may also be used at certain points throughout the instrument's high register, along with other fingerings, to alter sound quality as desired.

The right thumb operates four keys. The uppermost key is used to produce B♭2 and B♭3, and may be used in B4,F♯4, C5, D5, F5, and E♭5. The large circular key, otherwise known as the "pancake key", is held down for all the lowest notes from E2 down to B♭1. It is also used, like the whisper key, in additional fingerings for muting the sound. For example, in Ravel's "Boléro", the bassoon is asked to play the ostinato on G4. This is easy to perform with the normal fingering for G4, but Ravel directs that the player should also depress the E2 key (pancake key) to mute the sound (this being written with Buffet system in mind; the G fingering on which involves the Bb key – sometimes called "French" G on Heckel). The next key operated by the right thumb is known as the "spatula key": its primary use is to produce F♯2 and F♯3. The lowermost key is used less often: it is used to produce A♭2 (G♯2) and A♭3 (G♯3), in a manner that avoids sliding the right fourth finger from another note.

The four fingers of the left hand can each be used in two different positions. The key normally operated by the index finger is primarily used for E5, also serving for trills in the lower register. Its main assignment is the upper tone hole. This hole can be closed fully, or partially by rolling down the finger. This half-holing technique is used to overblow F♯3, G3 and G♯3. The middle finger typically stays on the centre hole on the tenor joint. It can also move to a lever used for E♭5, also a trill key. The ring finger operates, on most models, one key. Some bassoons have an alternate E♭ key above the tone hole, predominantly for trills, but many do not. The smallest finger operates two side keys on the bass joint. The lower key is typically used for C♯2, but can be used for muting or flattening notes in the tenor register. The upper key is used for E♭2, E4, F4, F♯4, A4, B♭4, B4, C5, C♯5, and D5; it flattens G3 and is the standard fingering for it in many places that tune to lower Hertz levels such as A440.

The four fingers of the right hand have at least one assignment each. The index finger stays over one hole, except that when E♭5 is played a side key at the top of the boot is used (this key also provides a C♯3 trill, albeit sharp on D). The middle finger remains stationary over the hole with a ring around it, and this ring and other pads are lifted when the smallest finger on the right hand pushes a lever. The ring finger typically remains stationary on the lower ring-finger key. However, the upper ring-finger key can be used, typically for B♭2 and B♭3, in place of the top thumb key on the front of the boot joint; this key comes from the oboe, and some bassoons do not have it because the thumb fingering is practically universal. The smallest finger operates three keys. The backmost one, closest to the bassoonist, is held down throughout most of the bass register. F♯4 may be created with this key, as well as G4, B♭4, B4, and C5 (the latter three employing solely it to flatten and stabilise the pitch). The lowest key for the smallest finger on the right hand is primarily used for A♭2 (G♯2) and A♭3 (G♯3) but can be used to improve D5, E♭5, and F5. The frontmost key is used, in addition to the thumb key, to create G♭2 and G♭3; on many bassoons this key operates a different tone hole to the thumb key and produces a slightly flatter F♯ ("duplicated F♯"); some techniques use one as standard for both octaves and the other for utility, but others use the thumb key for the lower and the fourth finger for the higher.

Extended techniques
Many extended techniques can be performed on the bassoon, such as multiphonics, flutter-tonguing, circular breathing, double tonguing, and harmonics. In the case of the bassoon, flutter-tonguing may be accomplished by "gargling" in the back of the throat as well as by the conventional method of rolling Rs. Multiphonics on the bassoon are plentiful, and can be achieved by using particular alternative fingerings, but are generally heavily influenced by embouchure position. Also, again using certain fingerings, notes may be produced on the instrument that sound lower pitches than the actual range of the instrument. These notes tend to sound very gravelly and out of tune, but technically sound below the low B♭.

The bassoonist may also produce lower notes than the bottom B♭ by extending the length of bell. This can be achieved by inserting a specially made "low A extension" into the bell, but may also be achieved with a small paper or rubber tube or a clarinet/cor anglais bell sitting inside the bassoon bell (although the note may tend sharp). The effect of this is to convert the lower B♭ into a lower note, almost always A natural; this broadly lowers the pitch of the instrument (most noticeably in the lower register) and will often accordingly convert the lowest B to B♭ (and render the neighbouring C very flat). The idea of using low A was begun by Richard Wagner, who wanted to extend the range of the bassoon. Many passages in his later operas require the low A as well as the B-flat immediately above it; this is possible on a normal bassoon using an extension which also flattens low B to B♭, but all extensions to the bell have significant effects on intonation and sound quality in the bottom register of the instrument, and passages such as this are more often realised with comparative ease by the contrabassoon.

Some bassoons have been specially made to allow bassoonists to realize similar passages. These bassoons are made with a "Wagner bell" which is an extended bell with a key for both the low A and the low B-flat, but they are not widespread; bassoons with Wagner bells suffer similar intonational problems as a bassoon with an ordinary A extension, and a bassoon must be constructed specifically to accommodate one, making the extension option far less complicated. Extending the bassoon's range even lower than the A, though possible, would have even stronger effects on pitch and make the instrument effectively unusable.

Despite the logistic difficulties of the note, Wagner was not the only composer to write the low A. Another composer who has required the bassoon to be chromatic down to low A is Gustav Mahler. Richard Strauss also calls for the low A in his opera Intermezzo. Some works have optional low As, as in Carl Nielsen's Wind Quintet, op. 43, which includes an optional low A for the final cadence of the work.

Learning the bassoon
The complex fingering system and the expense and lack of access to quality bassoon reeds can make the bassoon more of a challenge to learn than some of the other woodwind instruments. Cost is another factor in a person's decision to pursue the bassoon. Prices may range from US$7,000 to over $45,000 for a high-quality instrument. In North America, schoolchildren may take up bassoon only after starting on another reed instrument, such as clarinet or saxophone.

Students in America often begin to pursue the study of bassoon performance and technique in the middle years of their music education, often in association with their school band program. Students are often provided with a school instrument and encouraged to pursue lessons with private instructors. Students typically receive instruction in proper posture, hand position, embouchure, repertoire, and tone production.

title: Bassoon


text:
Talk:Boeing

Boeing whistleblower found dead?
Would this be noteworthy to mention in the article somewhere? https://www.washingtonpost.com/transportation/2024/03/12/boeing-whistleblower-dead-john-barnett/ https://time.com/6900123/boeing-whistleblower-john-barnett-found-dead-deposition-safety/ (Discuss 0nshore's contributions!!!) 12:26, 12 March 2024 (UTC)

 * it should be in here, yes Equirax (talk) 08:42, 16 March 2024 (UTC)
 * Second Boeing whistleblower dies-Df (talk) 16:30, 5 May 2024 (UTC)
 * There is a discussion below about how to best include this information. It has yet to reach a conclusion. -  ZLEA  T \ C 21:15, 5 May 2024 (UTC)

Probably not useful, but interesting and funny
New Far-Right Conspiracy Claims Boeing’s Accidents Are Intentional Doug Weller  talk 12:10, 16 March 2024 (UTC)
 * Interesting, but it’s not the strangest aviation conspiracy theory I’ve seen. I once dealt with a user who claimed that Donald Trump himself was responsible for the 2022 Dallas airshow mid-air collision. -  ZLEA  T \ C 15:41, 16 March 2024 (UTC)
 * If I recall correctly, they also claimed that the Commemorative Air Force (formerly known as the Confederate Air Force) was the literal air force of the underground Confederate States of America. - ZLEA  T \ C 15:43, 16 March 2024 (UTC)
 * It has to be read to be believed. - ZLEA  T \ C 15:46, 16 March 2024 (UTC)

Wing falling apart - passenger having to notify flight attendants
Hi everyone! I am hoping to add some information to the Boeing page concerning the recent Boeing flight which had to divert after a passenger saw the wing coming apart. This story hasn’t been added to the Wikipedia page yet, as it happened recently. We would add this to the page using the news articles below as sources.

Here are some news sources reporting on the incident: https://kdvr.com/news/local/united-flight-diverts-to-denver-due-to-wing-problem/amp/ https://www.independent.co.uk/travel/news-and-advice/boeing-plane-united-airlines-wing-san-francisco-boston-b2499865.html Graceruhl (talk) 16:23, 26 March 2024 (UTC)
 * That probably belongs at Boeing 757 and/or United Airlines for now. If the incident becomes more widely covered by reliable secondary sources, it may also be given an article of its own.  We cannot cover every accident and incident involving Boeing aircraft on this article, unless said accident or incident is relevant to the history of the company itself. -  ZLEA  T \ C 17:11, 26 March 2024 (UTC)

Intrigue/Conspiracies Section
Would it be useful to have a section devoted to the current conspiracies and intrigue surrounding Boeing? We could highlight both the conspiracies around these Boeing accidents being intentional and the whistleblower being found dead. https://www.wired.com/story/boeing-accidents-far-right-dei-conspiracy/?bxid=61ffffadba71511c13275c6c&cndid=68515061&esrc=MARTECH_ORDERFORM&source=Email_0_EDT_WIR_NEWSLETTER_0_DAILY_ZZ&utm_brand=wired&utm_campaign=aud-dev&utm_content=WIR_Daily_031624&utm_mailing=WIR_Daily_031624&utm_medium=email&utm_source=nl&utm_term=WIR_Daily_Active https://www.washingtonpost.com/transportation/2024/03/12/boeing-whistleblower-dead-john-barnett/ Graceruhl (talk) 18:11, 26 March 2024 (UTC)
 * The addition of a "Controversies" section has been discussed in the past (see Talk:Boeing/Archive 2). Personally, I have no opinion on the inclusion of such a section.  However, I'm not sure the conspiracy theories in question, especially the one alleging the crashes were intentional, are notable enough for inclusion even in a general "Controversies" section per WP:UNDUE. -  ZLEA  T \ C 20:04, 26 March 2024 (UTC)
 * I've reverted your WP:BOLD addition of the section for now. Given the highly sensitive nature of this incident, we should establish a consensus on how to best cover it. -  ZLEA  T \ C 05:31, 27 March 2024 (UTC)
 * There has been significant industry media reporting on Boeing's recent catalogue of failures and the consequent shaking of market confidence (e.g. I saw one industry member reported as saying that the pop-out plug door was "the last straw"). So I think that a section or subsection summarising these lapses and their cumulative effect would be justified. But I am not sure where or how best to place it, and we would need to be careful to keep conspiracy theories and other speculations or side issues out of it. — Cheers, Steelpillow (Talk) 19:30, 27 March 2024 (UTC)
 * This information would need to be added delicately to not add undue weight to it. WP:GEVAL says "Conspiracy theories, pseudoscience, Pseudohistory/speculative history, or plausible but unaccepted theories should not be legitimized through comparison to accepted academic scholarship. We do not take a stand on these issues as encyclopedia writers, for or against; we merely omit this information where including it would unduly legitimize it, and otherwise include and describe these ideas in their proper context concerning established scholarship and the beliefs of the wider world." KittyHawkFlyer (talk) 23:14, 29 March 2024 (UTC)
 * Given that a second whistleblower was found dead today, I think information on the actual events should be included. @KittyHawkFlyer makes a good point, but I don't think the conspiracy theories here are in opposition to established literature, just in opposition to the company line. If we can find a quality source for the claims, I think they can be included as long as it's made clear they're contested claims. TJS808 (talk) 03:34, 2 May 2024 (UTC)
 * As of the time of this reply, I have not found any coverage from reliable secondary sources about conspiracy theories about this second whistleblower's death. Given that most sources are reporting that he died of an MRSA infection, I doubt that there will be any serious allegations that Boeing was responsible for his death.  Only time will tell, though. -  ZLEA  T \ C 06:14, 2 May 2024 (UTC)
 * Conspiracy theories do not belong in an Encyclopedia. Stick to the facts. 50.47.192.107 (talk) 02:32, 3 May 2024 (UTC)
 * The existence of conspiracy theories can be covered if there are reliable secondary sources. We obviously cannot present said conspiracy theories as fact, and should be careful to not give them undue weight. -  ZLEA  T \ C 03:07, 3 May 2024 (UTC)
 * I think these conspiracy theories are blatant libel. They should be left out entirely. I think this article should be WP:OFFICE protected and any edits claiming murder should be deleted from the edit history ENTIRELY.  ANDROS1337  TALK 12:28, 6 May 2024 (UTC)
 * We can probably request the appropriate level of protection and WP:REVDEL if such disruption becomes a regular problem, but office actions would probably be a bit much. - ZLEA  T \ C 15:47, 6 May 2024 (UTC)

History section needs work
The history section needs work. For example, the Origins section seems like a nice overview. The Sea Launch section feels unnecessary. The Corporate headquarters moves is too long. Plus, the MAX issues needs to be mentioned here, either in addition to or instead of in a separate section. I can jump in and work on it... but I wanted to start a conversation here too. RickyCourtney (talk) 21:32, 27 March 2024 (UTC)

Boeing Computer Services
During the 1980s, there was a Boeing company called Boeing Computer Services (BCS). I'm not sure when it ceased to exist, nor whether it was absorbed back in to the parent company or sold off. I worked in its AI center from 1984 to 1987, so it at least existed during that time. It also developed Boeing Calc, which has an article Boeing_Calc. That article mentions the company and has a link to its article, but that link redirects here. Dunno if BCS was deemed not important enough to warrant a separate Wikipedia article, but if not it seems like it should at least be mentioned here. Mcswell (talk) 21:48, 6 May 2024 (UTC)
 * If there are enough reliable secondary sources covering BCS, then feel free to start an article on the company. Just know that as a former employee, you may have a WP:COI and might want to start the article as a draft. - 22:19, 6 May 2024 (UTC)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Talk:Boeing


text:
Bipedalism

Bipedalism is a form of terrestrial locomotion where an animal moves by means of its two rear (or lower) limbs or legs. An animal or machine that usually moves in a bipedal manner is known as a biped, meaning 'two feet' (from Latin bis 'double' and pes 'foot'). Types of bipedal movement include walking or running (a bipedal gait) and hopping.

Several groups of modern species are habitual bipeds whose normal method of locomotion is two-legged. In the Triassic period some groups of archosaurs (a group that includes crocodiles and dinosaurs) developed bipedalism; among the dinosaurs, all the early forms and many later groups were habitual or exclusive bipeds; the birds are members of a clade of exclusively bipedal dinosaurs, the theropods. Within mammals, habitual bipedalism has evolved multiple times, with the macropods, kangaroo rats and mice, springhare, hopping mice, pangolins and hominin apes (australopithecines, including humans) as well as various other extinct groups evolving the trait independently. A larger number of modern species intermittently or briefly use a bipedal gait. Several lizard species move bipedally when running, usually to escape from threats. Many primate and bear species will adopt a bipedal gait in order to reach food or explore their environment, though there are a few cases where they walk on their hind limbs only. Several arboreal primate species, such as gibbons and indriids, exclusively walk on two legs during the brief periods they spend on the ground. Many animals rear up on their hind legs while fighting or copulating. Some animals commonly stand on their hind legs to reach food, keep watch, threaten a competitor or predator, or pose in courtship, but do not move bipedally.

Etymology
The word is derived from the Latin words bi(s) 'two' and ped- 'foot', as contrasted with quadruped 'four feet'.

Advantages
Limited and exclusive bipedalism can offer a species several advantages. Bipedalism raises the head; this allows a greater field of vision with improved detection of distant dangers or resources, access to deeper water for wading animals and allows the animals to reach higher food sources with their mouths. While upright, non-locomotory limbs become free for other uses, including manipulation (in primates and rodents), flight (in birds), digging (in the giant pangolin), combat (in bears, great apes and the large monitor lizard) or camouflage.

The maximum bipedal speed appears slower than the maximum speed of quadrupedal movement with a flexible backbone – both the ostrich and the red kangaroo can reach speeds of 70 km/h, while the cheetah can exceed 100 km/h. Even though bipedalism is slower at first, over long distances, it has allowed humans to outrun most other animals according to the endurance running hypothesis. Bipedality in kangaroo rats has been hypothesized to improve locomotor performance, which could aid in escaping from predators.

Facultative and obligate bipedalism
Zoologists often label behaviors, including bipedalism, as "facultative" (i.e. optional) or "obligate" (the animal has no reasonable alternative). Even this distinction is not completely clear-cut — for example, humans other than infants normally walk and run in biped fashion, but almost all can crawl on hands and knees when necessary. There are even reports of humans who normally walk on all fours with their feet but not their knees on the ground, but these cases are a result of conditions such as Uner Tan syndrome — very rare genetic neurological disorders rather than normal behavior. Even if one ignores exceptions caused by some kind of injury or illness, there are many unclear cases, including the fact that "normal" humans can crawl on hands and knees. This article therefore avoids the terms "facultative" and "obligate", and focuses on the range of styles of locomotion normally used by various groups of animals. Normal humans may be considered "obligate" bipeds because the alternatives are very uncomfortable and usually only resorted to when walking is impossible.

Movement
There are a number of states of movement commonly associated with bipedalism.
 * 1) Standing. Staying still on both legs. In most bipeds this is an active process, requiring constant adjustment of balance.
 * 2) Walking. One foot in front of another, with at least one foot on the ground at any time.
 * 3) Running. One foot in front of another, with periods where both feet are off the ground.
 * 4) Jumping/hopping. Moving by a series of jumps with both feet moving together.

Bipedal animals
The great majority of living terrestrial vertebrates are quadrupeds, with bipedalism exhibited by only a handful of living groups. Humans, gibbons and large birds walk by raising one foot at a time. On the other hand, most macropods, smaller birds, lemurs and bipedal rodents move by hopping on both legs simultaneously. Tree kangaroos are able to walk or hop, most commonly alternating feet when moving arboreally and hopping on both feet simultaneously when on the ground.

Extant reptiles
Many species of lizards become bipedal during high-speed, sprint locomotion, including the world's fastest lizard, the spiny-tailed iguana (genus Ctenosaura).

Early reptiles and lizards
The first known biped is the bolosaurid Eudibamus whose fossils date from 290 million years ago. Its long hind-legs, short forelegs, and distinctive joints all suggest bipedalism. The species became extinct in the early Permian.

Birds
All birds are bipeds, as is the case for all theropod dinosaurs. However, hoatzin chicks have claws on their wings which they use for climbing.

Other archosaurs
Bipedalism evolved more than once in archosaurs, the group that includes both dinosaurs and crocodilians. All dinosaurs are thought to be descended from a fully bipedal ancestor, perhaps similar to Eoraptor.

Dinosaurs diverged from their archosaur ancestors approximately 230 million years ago during the Middle to Late Triassic period, roughly 20 million years after the Permian-Triassic extinction event wiped out an estimated 95 percent of all life on Earth. Radiometric dating of fossils from the early dinosaur genus Eoraptor establishes its presence in the fossil record at this time. Paleontologists suspect Eoraptor resembles the common ancestor of all dinosaurs; if this is true, its traits suggest that the first dinosaurs were small, bipedal predators. The discovery of primitive, dinosaur-like ornithodirans such as Marasuchus and Lagerpeton in Argentinian Middle Triassic strata supports this view; analysis of recovered fossils suggests that these animals were indeed small, bipedal predators.

Bipedal movement also re-evolved in a number of other dinosaur lineages such as the iguanodonts. Some extinct members of Pseudosuchia, a sister group to the avemetatarsalians (the group including dinosaurs and relatives), also evolved bipedal forms – a poposauroid from the Triassic, Effigia okeeffeae, is thought to have been bipedal. Pterosaurs were previously thought to have been bipedal, but recent trackways have all shown quadrupedal locomotion.

Mammals
A number of groups of extant mammals have independently evolved bipedalism as their main form of locomotion - for example humans, ground pangolins, the extinct giant ground sloths, numerous species of jumping rodents and macropods. Humans, as their bipedalism has been extensively studied, are documented in the next section. Macropods are believed to have evolved bipedal hopping only once in their evolution, at some time no later than 45 million years ago.

Bipedal movement is less common among mammals, most of which are quadrupedal. All primates possess some bipedal ability, though most species primarily use quadrupedal locomotion on land. Primates aside, the macropods (kangaroos, wallabies and their relatives), kangaroo rats and mice, hopping mice and springhare move bipedally by hopping. Very few non-primate mammals commonly move bipedally with an alternating leg gait. Exceptions are the ground pangolin and in some circumstances the tree kangaroo. One black bear, Pedals, became famous locally and on the internet for having a frequent bipedal gait, although this is attributed to injuries on the bear's front paws. A two-legged fox was filmed in a Derbyshire garden in 2023, most likely having been born that way.

Primates
Most bipedal animals move with their backs close to horizontal, using a long tail to balance the weight of their bodies. The primate version of bipedalism is unusual because the back is close to upright (completely upright in humans), and the tail may be absent entirely. Many primates can stand upright on their hind legs without any support. Chimpanzees, bonobos, gorillas, gibbons and baboons exhibit forms of bipedalism. On the ground sifakas move like all indrids with bipedal sideways hopping movements of the hind legs, holding their forelimbs up for balance. Geladas, although usually quadrupedal, will sometimes move between adjacent feeding patches with a squatting, shuffling bipedal form of locomotion. However, they can only do so for brief amounts, as their bodies are not adapted for constant bipedal locomotion.

Humans are the only primates who are normally biped, due to an extra curve in the spine which stabilizes the upright position, as well as shorter arms relative to the legs than is the case for the nonhuman great apes. The evolution of human bipedalism began in primates about four million years ago, or as early as seven million years ago with Sahelanthropus or about 12 million years ago with Danuvius guggenmosi. One hypothesis for human bipedalism is that it evolved as a result of differentially successful survival from carrying food to share with group members, although there are alternative hypotheses.

Injured chimpanzees and bonobos have been capable of sustained bipedalism.
 * Injured individuals

Three captive primates, one macaque Natasha and two chimps, Oliver and Poko (chimpanzee), were found to move bipedally. Natasha switched to exclusive bipedalism after an illness, while Poko was discovered in captivity in a tall, narrow cage. Oliver reverted to knuckle-walking after developing arthritis. Non-human primates often use bipedal locomotion when carrying food, or while moving through shallow water.

Limited bipedalism in mammals
Other mammals engage in limited, non-locomotory, bipedalism. A number of other animals, such as rats, raccoons, and beavers will squat on their hindlegs to manipulate some objects but revert to four limbs when moving (the beaver will move bipedally if transporting wood for their dams, as will the raccoon when holding food). Bears will fight in a bipedal stance to use their forelegs as weapons. A number of mammals will adopt a bipedal stance in specific situations such as for feeding or fighting. Ground squirrels and meerkats will stand on hind legs to survey their surroundings, but will not walk bipedally. Dogs (e.g. Faith) can stand or move on two legs if trained, or if birth defect or injury precludes quadrupedalism. The gerenuk antelope stands on its hind legs while eating from trees, as did the extinct giant ground sloth and chalicotheres. The spotted skunk will walk on its front legs when threatened, rearing up on its front legs while facing the attacker so that its anal glands, capable of spraying an offensive oil, face its attacker.

Limited bipedalism in non-mammals (and non-birds)
Bipedalism is unknown among the amphibians. Among the non-archosaur reptiles bipedalism is rare, but it is found in the "reared-up" running of lizards such as agamids and monitor lizards. Many reptile species will also temporarily adopt bipedalism while fighting. One genus of basilisk lizard can run bipedally across the surface of water for some distance. Among arthropods, cockroaches are known to move bipedally at high speeds. Bipedalism is rarely found outside terrestrial animals, though at least two species of octopus walk bipedally on the sea floor using two of their arms, allowing the remaining arms to be used to camouflage the octopus as a mat of algae or a floating coconut.

Evolution of human bipedalism
There are at least twelve distinct hypotheses as to how and why bipedalism evolved in humans, and also some debate as to when. Bipedalism evolved well before the large human brain or the development of stone tools. Bipedal specializations are found in Australopithecus fossils from 4.2 to 3.9 million years ago and recent studies have suggested that obligate bipedal hominid species were present as early as 7 million years ago. Nonetheless, the evolution of bipedalism was accompanied by significant evolutions in the spine including the forward movement in position of the foramen magnum, where the spinal cord leaves the cranium. Recent evidence regarding modern human sexual dimorphism (physical differences between male and female) in the lumbar spine has been seen in pre-modern primates such as Australopithecus africanus. This dimorphism has been seen as an evolutionary adaptation of females to bear lumbar load better during pregnancy, an adaptation that non-bipedal primates would not need to make. Adapting bipedalism would have required less shoulder stability, which allowed the shoulder and other limbs to become more independent of each other and adapt for specific suspensory behaviors. In addition to the change in shoulder stability, changing locomotion would have increased the demand for shoulder mobility, which would have propelled the evolution of bipedalism forward. The different hypotheses are not necessarily mutually exclusive and a number of selective forces may have acted together to lead to human bipedalism. It is important to distinguish between adaptations for bipedalism and adaptations for running, which came later still.

The form and function of modern-day humans' upper bodies appear to have evolved from living in a more forested setting. Living in this kind of environment would have made it so that being able to travel arboreally would have been advantageous at the time. Although different to human walking, bipedal locomotion in trees was thought to be advantageous. It has also been proposed that, like some modern-day apes, early hominins had undergone a knuckle-walking stage prior to adapting the back limbs for bipedality while retaining forearms capable of grasping. Numerous causes for the evolution of human bipedalism involve freeing the hands for carrying and using tools, sexual dimorphism in provisioning, changes in climate and environment (from jungle to savanna) that favored a more elevated eye-position, and to reduce the amount of skin exposed to the tropical sun. It is possible that bipedalism provided a variety of benefits to the hominin species, and scientists have suggested multiple reasons for evolution of human bipedalism. There is also not only the question of why the earliest hominins were partially bipedal but also why hominins became more bipedal over time. For example, the postural feeding hypothesis describes how the earliest hominins became bipedal for the benefit of reaching food in trees while the savanna-based theory describes how the late hominins that started to settle on the ground became increasingly bipedal.

Multiple factors
Napier (1963) argued that it is unlikely that a single factor drove the evolution of bipedalism. He stated "It seems unlikely that any single factor was responsible for such a dramatic change in behaviour. In addition to the advantages of accruing from ability to carry objects – food or otherwise – the improvement of the visual range and the freeing of the hands for purposes of defence and offence may equally have played their part as catalysts." Sigmon (1971) demonstrated that chimpanzees exhibit bipedalism in different contexts, and one single factor should be used to explain bipedalism: preadaptation for human bipedalism. Day (1986) emphasized three major pressures that drove evolution of bipedalism: food acquisition, predator avoidance, and reproductive success. Ko (2015) stated that there are two questions main regarding bipedalism 1. Why were the earliest hominins partially bipedal? and 2. Why did hominins become more bipedal over time? He argued that these questions can be answered with combination of prominent theories such as Savanna-based, Postural feeding, and Provisioning.

Savannah-based theory
According to the Savanna-based theory, hominines came down from the tree's branches and adapted to life on the savanna by walking erect on two feet. The theory suggests that early hominids were forced to adapt to bipedal locomotion on the open savanna after they left the trees. One of the proposed mechanisms was the knuckle-walking hypothesis, which states that human ancestors used quadrupedal locomotion on the savanna, as evidenced by morphological characteristics found in Australopithecus anamensis and Australopithecus afarensis forelimbs, and that it is less parsimonious to assume that knuckle walking developed twice in genera Pan and Gorilla instead of evolving it once as synapomorphy for Pan and Gorilla before losing it in Australopithecus. The evolution of an orthograde posture would have been very helpful on a savanna as it would allow the ability to look over tall grasses in order to watch out for predators, or terrestrially hunt and sneak up on prey. It was also suggested in P. E. Wheeler's "The evolution of bipedality and loss of functional body hair in hominids", that a possible advantage of bipedalism in the savanna was reducing the amount of surface area of the body exposed to the sun, helping regulate body temperature. In fact, Elizabeth Vrba's turnover pulse hypothesis supports the savanna-based theory by explaining the shrinking of forested areas due to global warming and cooling, which forced animals out into the open grasslands and caused the need for hominids to acquire bipedality.

Others state hominines had already achieved the bipedal adaptation that was used in the savanna. The fossil evidence reveals that early bipedal hominins were still adapted to climbing trees at the time they were also walking upright. It is possible that bipedalism evolved in the trees, and was later applied to the savanna as a vestigial trait. Humans and orangutans are both unique to a bipedal reactive adaptation when climbing on thin branches, in which they have increased hip and knee extension in relation to the diameter of the branch, which can increase an arboreal feeding range and can be attributed to a convergent evolution of bipedalism evolving in arboreal environments. Hominine fossils found in dry grassland environments led anthropologists to believe hominines lived, slept, walked upright, and died only in those environments because no hominine fossils were found in forested areas. However, fossilization is a rare occurrence—the conditions must be just right in order for an organism that dies to become fossilized for somebody to find later, which is also a rare occurrence. The fact that no hominine fossils were found in forests does not ultimately lead to the conclusion that no hominines ever died there. The convenience of the savanna-based theory caused this point to be overlooked for over a hundred years.

Some of the fossils found actually showed that there was still an adaptation to arboreal life. For example, Lucy, the famous Australopithecus afarensis, found in Hadar in Ethiopia, which may have been forested at the time of Lucy's death, had curved fingers that would still give her the ability to grasp tree branches, but she walked bipedally. "Little Foot", a nearly-complete specimen of Australopithecus africanus, has a divergent big toe as well as the ankle strength to walk upright. "Little Foot" could grasp things using his feet like an ape, perhaps tree branches, and he was bipedal. Ancient pollen found in the soil in the locations in which these fossils were found suggest that the area used to be much more wet and covered in thick vegetation and has only recently become the arid desert it is now.

Traveling efficiency hypothesis
An alternative explanation is that the mixture of savanna and scattered forests increased terrestrial travel by proto-humans between clusters of trees, and bipedalism offered greater efficiency for long-distance travel between these clusters than quadrupedalism. In an experiment monitoring chimpanzee metabolic rate via oxygen consumption, it was found that the quadrupedal and bipedal energy costs were very similar, implying that this transition in early ape-like ancestors would not have been very difficult or energetically costing. This increased travel efficiency is likely to have been selected for as it assisted foraging across widely dispersed resources.

Postural feeding hypothesis
The postural feeding hypothesis has been recently supported by Dr. Kevin Hunt, a professor at Indiana University. This hypothesis asserts that chimpanzees were only bipedal when they eat. While on the ground, they would reach up for fruit hanging from small trees and while in trees, bipedalism was used to reach up to grab for an overhead branch. These bipedal movements may have evolved into regular habits because they were so convenient in obtaining food. Also, Hunt's hypotheses states that these movements coevolved with chimpanzee arm-hanging, as this movement was very effective and efficient in harvesting food. When analyzing fossil anatomy, Australopithecus afarensis has very similar features of the hand and shoulder to the chimpanzee, which indicates hanging arms. Also, the Australopithecus hip and hind limb very clearly indicate bipedalism, but these fossils also indicate very inefficient locomotive movement when compared to humans. For this reason, Hunt argues that bipedalism evolved more as a terrestrial feeding posture than as a walking posture.

A related study conducted by University of Birmingham, Professor Susannah Thorpe examined the most arboreal great ape, the orangutan, holding onto supporting branches in order to navigate branches that were too flexible or unstable otherwise. In more than 75 percent of observations, the orangutans used their forelimbs to stabilize themselves while navigating thinner branches. Increased fragmentation of forests where A. afarensis as well as other ancestors of modern humans and other apes resided could have contributed to this increase of bipedalism in order to navigate the diminishing forests. Findings also could shed light on discrepancies observed in the anatomy of A. afarensis, such as the ankle joint, which allowed it to "wobble" and long, highly flexible forelimbs. If bipedalism started from upright navigation in trees, it could explain both increased flexibility in the ankle as well as long forelimbs which grab hold of branches.

Provisioning model
One theory on the origin of bipedalism is the behavioral model presented by C. Owen Lovejoy, known as "male provisioning". Lovejoy theorizes that the evolution of bipedalism was linked to monogamy. In the face of long inter-birth intervals and low reproductive rates typical of the apes, early hominids engaged in pair-bonding that enabled greater parental effort directed towards rearing offspring. Lovejoy proposes that male provisioning of food would improve the offspring survivorship and increase the pair's reproductive rate. Thus the male would leave his mate and offspring to search for food and return carrying the food in his arms walking on his legs. This model is supported by the reduction ("feminization") of the male canine teeth in early hominids such as Sahelanthropus tchadensis and Ardipithecus ramidus, which along with low body size dimorphism in Ardipithecus and Australopithecus,  suggests a reduction in inter-male antagonistic behavior in early hominids. In addition, this model is supported by a number of modern human traits associated with concealed ovulation (permanently enlarged breasts, lack of sexual swelling) and low sperm competition (moderate sized testes, low sperm mid-piece volume) that argues against recent adaptation to a polygynous reproductive system.

However, this model has been debated, as others have argued that early bipedal hominids were instead polygynous. Among most monogamous primates, males and females are about the same size. That is sexual dimorphism is minimal, and other studies have suggested that Australopithecus afarensis males were nearly twice the weight of females. However, Lovejoy's model posits that the larger range a provisioning male would have to cover (to avoid competing with the female for resources she could attain herself) would select for increased male body size to limit predation risk. Furthermore, as the species became more bipedal, specialized feet would prevent the infant from conveniently clinging to the mother - hampering the mother's freedom and thus make her and her offspring more dependent on resources collected by others. Modern monogamous primates such as gibbons tend to be also territorial, but fossil evidence indicates that Australopithecus afarensis lived in large groups. However, while both gibbons and hominids have reduced canine sexual dimorphism, female gibbons enlarge ('masculinize') their canines so they can actively share in the defense of their home territory. Instead, the reduction of the male hominid canine is consistent with reduced inter-male aggression in a pair-bonded though group living primate.

Early bipedalism in homininae model
Recent studies of 4.4 million years old Ardipithecus ramidus suggest bipedalism. It is thus possible that bipedalism evolved very early in homininae and was reduced in chimpanzee and gorilla when they became more specialized. Other recent studies of the foot structure of Ardipithecus ramidus suggest that the species was closely related to African-ape ancestors. This possibly provides a species close to the true connection between fully bipedal hominins and quadruped apes. According to Richard Dawkins in his book "The Ancestor's Tale", chimps and bonobos are descended from Australopithecus gracile type species while gorillas are descended from Paranthropus. These apes may have once been bipedal, but then lost this ability when they were forced back into an arboreal habitat, presumably by those australopithecines from whom eventually evolved hominins. Early hominines such as Ardipithecus ramidus may have possessed an arboreal type of bipedalism that later independently evolved towards knuckle-walking in chimpanzees and gorillas and towards efficient walking and running in modern humans (see figure). It is also proposed that one cause of Neanderthal extinction was a less efficient running.

Warning display (aposematic) model
Joseph Jordania from the University of Melbourne recently (2011) suggested that bipedalism was one of the central elements of the general defense strategy of early hominids, based on aposematism, or warning display and intimidation of potential predators and competitors with exaggerated visual and audio signals. According to this model, hominids were trying to stay as visible and as loud as possible all the time. Several morphological and behavioral developments were employed to achieve this goal: upright bipedal posture, longer legs, long tightly coiled hair on the top of the head, body painting, threatening synchronous body movements, loud voice and extremely loud rhythmic singing/stomping/drumming on external subjects. Slow locomotion and strong body odor (both characteristic for hominids and humans) are other features often employed by aposematic species to advertise their non-profitability for potential predators.

Other behavioural models
There are a variety of ideas which promote a specific change in behaviour as the key driver for the evolution of hominid bipedalism. For example, Wescott (1967) and later Jablonski & Chaplin (1993) suggest that bipedal threat displays could have been the transitional behaviour which led to some groups of apes beginning to adopt bipedal postures more often. Others (e.g. Dart 1925) have offered the idea that the need for more vigilance against predators could have provided the initial motivation. Dawkins (e.g. 2004) has argued that it could have begun as a kind of fashion that just caught on and then escalated through sexual selection. And it has even been suggested (e.g. Tanner 1981:165) that male phallic display could have been the initial incentive, as well as increased sexual signaling in upright female posture.

Thermoregulatory model
The thermoregulatory model explaining the origin of bipedalism is one of the simplest theories so far advanced, but it is a viable explanation. Dr. Peter Wheeler, a professor of evolutionary biology, proposes that bipedalism raises the amount of body surface area higher above the ground which results in a reduction in heat gain and helps heat dissipation. When a hominid is higher above the ground, the organism accesses more favorable wind speeds and temperatures. During heat seasons, greater wind flow results in a higher heat loss, which makes the organism more comfortable. Also, Wheeler explains that a vertical posture minimizes the direct exposure to the sun whereas quadrupedalism exposes more of the body to direct exposure. Analysis and interpretations of Ardipithecus reveal that this hypothesis needs modification to consider that the forest and woodland environmental preadaptation of early-stage hominid bipedalism preceded further refinement of bipedalism by the pressure of natural selection. This then allowed for the more efficient exploitation of the hotter conditions ecological niche, rather than the hotter conditions being hypothetically bipedalism's initial stimulus. A feedback mechanism from the advantages of bipedality in hot and open habitats would then in turn make a forest preadaptation solidify as a permanent state.

Carrying models
Charles Darwin wrote that "Man could not have attained his present dominant position in the world without the use of his hands, which are so admirably adapted to the act of obedience of his will". Darwin (1871:52) and many models on bipedal origins are based on this line of thought. Gordon Hewes (1961) suggested that the carrying of meat "over considerable distances" (Hewes 1961:689) was the key factor. Isaac (1978) and Sinclair et al. (1986) offered modifications of this idea, as indeed did Lovejoy (1981) with his "provisioning model" described above. Others, such as Nancy Tanner (1981), have suggested that infant carrying was key, while others again have suggested stone tools and weapons drove the change. This stone-tools theory is very unlikely, as though ancient humans were known to hunt, the discovery of tools was not discovered for thousands of years after the origin of bipedalism, chronologically precluding it from being a driving force of evolution. (Wooden tools and spears fossilize poorly and therefore it is difficult to make a judgment about their potential usage.)

Wading models
The observation that large primates, including especially the great apes, that predominantly move quadrupedally on dry land, tend to switch to bipedal locomotion in waist deep water, has led to the idea that the origin of human bipedalism may have been influenced by waterside environments. This idea, labelled "the wading hypothesis", was originally suggested by the Oxford marine biologist Alister Hardy who said: "It seems to me likely that Man learnt to stand erect first in water and then, as his balance improved, he found he became better equipped for standing up on the shore when he came out, and indeed also for running." It was then promoted by Elaine Morgan, as part of the aquatic ape hypothesis, who cited bipedalism among a cluster of other human traits unique among primates, including voluntary control of breathing, hairlessness and subcutaneous fat. The "aquatic ape hypothesis", as originally formulated, has not been accepted or considered a serious theory within the anthropological scholarly community. Others, however, have sought to promote wading as a factor in the origin of human bipedalism without referring to further ("aquatic ape" related) factors. Since 2000 Carsten Niemitz has published a series of papers and a book on a variant of the wading hypothesis, which he calls the "amphibian generalist theory" (Amphibische Generalistentheorie).

Other theories have been proposed that suggest wading and the exploitation of aquatic food sources (providing essential nutrients for human brain evolution or critical fallback foods ) may have exerted evolutionary pressures on human ancestors promoting adaptations which later assisted full-time bipedalism. It has also been thought that consistent water-based food sources had developed early hominid dependency and facilitated dispersal along seas and rivers.

Consequences
Prehistoric fossil records show that early hominins first developed bipedalism before being followed by an increase in brain size. The consequences of these two changes in particular resulted in painful and difficult labor due to the increased favor of a narrow pelvis for bipedalism being countered by larger heads passing through the constricted birth canal. This phenomenon is commonly known as the obstetrical dilemma.

Non-human primates habitually deliver their young on their own, but the same cannot be said for modern-day humans. Isolated birth appears to be rare and actively avoided cross-culturally, even if birthing methods may differ between said cultures. This is due to the fact that the narrowing of the hips and the change in the pelvic angle caused a discrepancy in the ratio of the size of the head to the birth canal. The result of this is that there is greater difficulty in birthing for hominins in general, let alone to be doing it by oneself.

Physiology
Bipedal movement occurs in a number of ways and requires many mechanical and neurological adaptations. Some of these are described below.

Standing
Energy-efficient means of standing bipedally involve constant adjustment of balance, and of course these must avoid overcorrection. The difficulties associated with simple standing in upright humans are highlighted by the greatly increased risk of falling present in the elderly, even with minimal reductions in control system effectiveness.

Shoulder stability
Shoulder stability would decrease with the evolution of bipedalism. Shoulder mobility would increase because the need for a stable shoulder is only present in arboreal habitats. Shoulder mobility would support suspensory locomotion behaviors which are present in human bipedalism. The forelimbs are freed from weight-bearing requirements, which makes the shoulder a place of evidence for the evolution of bipedalism.

Walking
Unlike non-human apes that are able to practice bipedality such as Pan and Gorilla, hominins have the ability to move bipedally without the utilization of a bent-hip-bent-knee (BHBK) gait, which requires the engagement of both the hip and the knee joints. This human ability to walk is made possible by the spinal curvature humans have that non-human apes do not. Rather, walking is characterized by an "inverted pendulum" movement in which the center of gravity vaults over a stiff leg with each step. Force plates can be used to quantify the whole-body kinetic & potential energy, with walking displaying an out-of-phase relationship indicating exchange between the two. This model applies to all walking organisms regardless of the number of legs, and thus bipedal locomotion does not differ in terms of whole-body kinetics.

In humans, walking is composed of several separate processes:
 * Vaulting over a stiff stance leg
 * Passive ballistic movement of the swing leg
 * A short 'push' from the ankle prior to toe-off, propelling the swing leg
 * Rotation of the hips about the axis of the spine, to increase stride length
 * Rotation of the hips about the horizontal axis to improve balance during stance

Running
Early hominins underwent post-cranial changes in order to better adapt to bipedality, especially running. One of these changes is having longer hindlimbs proportional to the forelimbs and their effects. As previously mentioned, longer hindlimbs assist in thermoregulation by reducing the total surface area exposed to direct sunlight while simultaneously allowing for more space for cooling winds. Additionally, having longer limbs is more energy-efficient, since longer limbs mean that overall muscle strain is lessened. Better energy efficiency, in turn, means higher endurance, particularly when running long distances.

Running is characterized by a spring-mass movement. Kinetic and potential energy are in phase, and the energy is stored & released from a spring-like limb during foot contact, achieved by the plantar arch and the Achilles tendon in the foot and leg, respectively. Again, the whole-body kinetics are similar to animals with more limbs.

Musculature
Bipedalism requires strong leg muscles, particularly in the thighs. Contrast in domesticated poultry the well muscled legs, against the small and bony wings. Likewise in humans, the quadriceps and hamstring muscles of the thigh are both so crucial to bipedal activities that each alone is much larger than the well-developed biceps of the arms. In addition to the leg muscles, the increased size of the gluteus maximus in humans is an important adaptation as it provides support and stability to the trunk and lessens the amount of stress on the joints when running.

Respiration
Quadrupeds, have more restrictive breathing respire while moving than do bipedal humans. "Quadrupedal species normally synchronize the locomotor and respiratory cycles at a constant ratio of 1:1 (strides per breath) in both the trot and gallop. Human runners differ from quadrupeds in that while running they employ several phase-locked patterns (4:1, 3:1, 2:1, 1:1, 5:2, and 3:2), although a 2:1 coupling ratio appears to be favored. Even though the evolution of bipedal gait has reduced the mechanical constraints on respiration in man, thereby permitting greater flexibility in breathing pattern, it has seemingly not eliminated the need for the synchronization of respiration and body motion during sustained running."

Respiration through bipedality means that there is better breath control in bipeds, which can be associated with brain growth. The modern brain utilizes approximately 20% of energy input gained through breathing and eating, as opposed to species like chimpanzees who use up twice as much energy as humans for the same amount of movement. This excess energy, leading to brain growth, also leads to the development of verbal communication. This is because breath control means that the muscles associated with breathing can be manipulated into creating sounds. This means that the onset of bipedality, leading to more efficient breathing, may be related to the origin of verbal language.

Bipedal robots
For nearly the whole of the 20th century, bipedal robots were very difficult to construct and robot locomotion involved only wheels, treads, or multiple legs. Recent cheap and compact computing power has made two-legged robots more feasible. Some notable biped robots are ASIMO, HUBO, MABEL and QRIO. Recently, spurred by the success of creating a fully passive, un-powered bipedal walking robot, those working on such machines have begun using principles gleaned from the study of human and animal locomotion, which often relies on passive mechanisms to minimize power consumption.

title: Bipedalism