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Brown bear

The brown bear (Ursus arctos) is a large bear native to Eurasia and North America. It is one of the largest land carnivorans, rivaled in size only by its closest relative, the polar bear, which is much less variable in size and slightly bigger on average. The brown bear is a sexually dimorphic species, as adult males average around 30% larger in most populations. Brown bears are often not fully brown; the pelage can be reddish to yellowish-brown, and dark brown to cream in color. They are the only extant bears with a hump formed entirely of muscle on their shoulders. The paws are large and allow the bear to effectively dig through dirt. Its teeth are similar to those of other bears and reflect its dietary plasticity.

Throughout the brown bear's range, it inhabits mainly forested habitats in elevations of up to 5000 m. It is omnivorous, and consumes a variety of plant and animal species. Contrary to popular belief, the brown bear derives 90% of its diet from plants. When hunting, it will target animals as small as rodents, to those as large as moose or muskoxen. In parts of coastal Alaska, brown bears predominately feed on spawning salmon that come near shore to lay their eggs. For most of the year, it is a solitary animal that only associates when mating or raising cubs. Females give birth to an average of one to three cubs that remain with their mother for 1.5 to 4.5 years. They are long lived animals, with an average lifespan of 25 years in the wild. Relative to its body size, the brown bear has an exceptionally large brain for a land carnivore. This large brain allows for high cognitive abilities, such as tool use. Attacks on humans, though widely reported, are generally rare.

While the brown bear's range has shrunk, and it has faced local extinctions across its wide range, it remains listed as a least concern species by the International Union for Conservation of Nature (IUCN) with a total estimated population in 2017 of 110,000. Populations that were hunted to extinction in the 19th and 20th centuries are the Atlas bear of North Africa and the Californian, Ungavan and Mexican populations of the grizzly bear of North America. Many of the populations in the southern parts of Eurasia are highly endangered as well. One of the smaller-bodied forms, the Himalayan brown bear, is critically endangered, occupying only 2% of its former range and threatened by uncontrolled poaching for its body parts. The Marsican brown bear of central Italy is one of several currently isolated populations of the Eurasian brown bear and is believed to have a population of just c. 50 bears.

The brown bear is considered a charismatic megafauna, and have been kept in zoos since ancient times. They have been tamed and trained to perform in circuses and other acts. For thousands of years, brown bears have found a predominant role in human culture, and are often featured in literature, art, folklore and mythology.

Etymology
The brown bear is sometimes referred to as the bruin, from Middle English. This name originated in the fable History of Reynard the Fox translated by William Caxton from Middle Dutch bruun or bruyn, meaning brown (the color). In the mid-19th century United States, the brown bear was termed "Old Ephraim" and sometimes as "Moccasin Joe".

The scientific name of the brown bear, Ursus arctos, comes from the Latin ursus, meaning "bear", and the Greek ἄρκτος/, also meaning "bear".

Taxonomy and subspecies

Carl Linnaeus scientifically described the species under the name Ursus arctos in the 1758 edition of Systema Naturae. Brown bear taxonomy and subspecies classification has been described as "formidable and confusing," with few authorities listing the same specific set of subspecies. There are hundreds of obsolete brown bear subspecies. As many as 90 subspecies have been proposed. A 2008 DNA analysis identified as few as five main clades which contain all extant brown bears, while a 2017 phylogenetic study revealed nine clades, including one representing polar bears. , 15 extant or recently extinct subspecies were recognized by the general scientific community.

DNA analysis shows that, apart from recent human-caused population fragmentation, brown bears in North America are generally part of a single interconnected population system, with the exception of the population (or subspecies) in the Kodiak Archipelago, which has probably been isolated since the end of the last Ice Age. These data demonstrate that U. a. gyas, U. a. horribilis, U. a. sitkensis and U. a. stikeenensis are not distinct or cohesive groups, and would more accurately be described as ecotypes. For example, brown bears in any particular region of the Alaska coast are more closely related to adjacent grizzly bears than to distant populations of brown bears.

The history of the bears of the Alexander Archipelago is unusual in that these island populations carry polar bear DNA, presumably originating from a population of polar bears that was left behind at the end of the Pleistocene, but have since been connected with adjacent mainland populations through movement of males, to the point where their nuclear genomes are now more than 90% of brown bear ancestry. MtDNA analysis revealed that brown bears are apparently divided into five different clades, some of which coexist or co-occur in different regions.

Evolution
The brown bear is one of eight extant species in the bear family Ursidae and of six extant species in the subfamily Ursinae.

The brown bear is thought to have evolved from the Etruscan bear (Ursus etruscus) in Asia during the early Pliocene. A genetic analysis indicated that the brown bear lineage diverged from the cave bear species complex approximately 1.2–1.4 million years ago, but did not clarify if U. savini persisted as a paraspecies for the brown bear before perishing. The oldest brown bear fossils occur in Asia from about 500,000 to 300, 000 years ago. They entered Europe 250,000 years ago and North Africa shortly after. Brown bear remains from the Pleistocene period are common in the British Isles, where amongst other factors, they may have contributed to the extinction of cave bears (Ursus spelaeus).

Brown bears first emigrated to North America from Eurasia via Beringia during the Illinoian Glaciation. Genetic evidence suggests several brown bear populations migrated into North America, aligning with the glacial cycles of the Pleistocene. The founding population of most North American brown bears arrived first, with the genetic lineage developing around ~177,000 BP. Genetic divergences suggest brown bears first migrated south during MIS-5 (~92,000–83,000 BP) upon the opening of the ice-free corridor, After a local extinction in Beringia ~33,000 BP, two new but closely related lineages repopulated Alaska and northern Canada from Eurasia after the Last Glacial Maximum (>25,000 BP).

Brown bear fossils discovered in Ontario, Ohio, Kentucky and Labrador show that the species occurred farther east than indicated in historic records. In North America, two types of the subspecies Ursus arctos horribilis are generally recognized—the coastal brown bear and the inland grizzly bear.

Hybrids

A grizzly–polar bear hybrid is a rare ursid hybrid resulting from a crossbreeding of a brown bear and a polar bear. It has occurred both in captivity and in the wild. In 2006, the occurrence of this hybrid was confirmed by testing the DNA of a strange-looking bear that had been shot in the Canadian Arctic, and seven more hybrids have since been confirmed in the same region, all descended from a single female polar bear. Previously, the hybrid had been produced in zoos and was considered a "cryptid" (a hypothesized animal for which there is no scientific proof of existence in the wild). Analyses of the genomes of bears have shown that introgression between species was widespread during the evolution of the genus Ursus, including the introgression of polar bear DNA introduced to brown bears during the Pleistocene.

Size
The brown bear is the most variable in size of modern bears. The typical size depends upon which population it is from, and most accepted subtypes vary widely in size. This is in part due to sexual dimorphism, as male brown bears average at least 30% larger in most subtypes. Individual bears vary in size seasonally, weighing the least in spring due to lack of foraging during hibernation, and the most in late fall, after a period of hyperphagia to put on additional weight to prepare for hibernation.

Brown bears generally weigh 80 to 600 kg, with males outweighing females. They have a head-and-body length of 1.4 to 2.8 m and a shoulder height of 70 to 153 cm. The tail is relatively short, as in all bears, ranging from 6 to 22 cm in length. The smallest brown bears, females during spring among barren-ground populations, can weigh so little as to roughly match the body mass of males of the smallest living bear species, the sun bear (Helarctos malayanus), while the largest coastal populations attain sizes broadly similar to those of the largest living bear species, the polar bear. Interior brown bears are generally smaller than is often perceived, being around the same weight as an average lion, at an average of 180 kg in males and 135 kg in females, whereas adults of the coastal populations weigh about twice as much. The average weight of adult male bears from 19 populations, was found to be 217 kg while adult females from 24 populations were found to average 152 kg.

Coloration
Brown bears are often not fully brown. They have long, thick fur, with a moderately elongated mane at the back of the neck which varies somewhat across the types. In India, brown bears can be reddish with silver-tipped hairs, while in China brown bears are bicolored, with a yellowish-brown or whitish collar across the neck, chest and shoulders. Even within well-defined subspecies, individuals may show highly variable hues of brown. North American grizzlies can be dark brown (almost black) to cream (almost white) or yellowish-brown and often have darker-colored legs. The common name "grizzly" stems from their typical coloration, with the hairs on their back usually being brownish-black at the base and whitish-cream at the tips, giving them their distinctive "grizzled" color. Apart from the cinnamon subspecies of the American black bear (U. americanus cinnamonum), the brown bear is the only modern bear species to typically appear truly brown. The winter fur is very thick and long, especially in northern subspecies, and can reach 11 to 12 cm at the withers. The winter hairs are thin, yet rough to the touch. The summer fur is much shorter and sparser, with its length and density varying geographically.

Cranial morphology and size

Adults have massive, heavily built concave skulls, which are large in proportion to the body. The projections of the skull are well developed. Skull lengths of Russian brown bears tend to be 31.5 to 45.5 cm for males, and 27.5 to 39.7 cm for females. The width of the zygomatic arches in males is 17.5 to 27.7 cm, and 14.7 to 24.7 cm in females. Brown bears have strong jaws: the incisors and canine teeth are large, with the lower canines being strongly curved. The first three molars of the upper jaw are underdeveloped and single crowned with one root. The second upper molar is smaller than the others, and is usually absent in adults. It is usually lost at an early age, leaving no trace of the alveolus in the jaw. The first three molars of the lower jaw are very weak, and are often lost at an early age. The teeth of brown bears reflect their dietary plasticity and are broadly similar to other bears. They are reliably larger than American black bears, but average smaller in molar length than polar bears. Brown bears have the broadest skull of any extant ursine bear.

Claws and feet
Brown bears have large, curved claws, with the front ones being larger than the back. They may reach 5 to 6 cm and measure 7 to 10 cm along the curve. Compared with the American black bear (Ursus americanus), the brown bear has longer and stronger claws, with a blunt curve. Due to their claw structure, in addition to their excessive weight, adult brown bears are not to be able to climb trees as well as black bears. In rare cases adult female brown bears have been seen scaling trees. The claws of a polar bear are quite different, being notably shorter but broader with a strong curve and sharper point. The species has large paws; the rear feet measures 21 to 36 cm long, while the forefeet tend to measure 40% less. Brown bears are the only extant bears with a hump at the top of their shoulder, which is made entirely of muscle. This feature having developed presumably for imparting more force in digging, helps during foraging and is used heavily in den construction prior to hibernation.

Distribution and habitat
Brown bears were once native to Europe, much of Asia, the Atlas Mountains of Africa, and North America, but are now extirpated in some areas, and their populations have greatly decreased in other areas. There are approximately 200,000 brown bears left in the world. The largest populations are in Russia with 130,000, the United States with 32,500, and Canada with around 25,000. Brown bears live in Alaska, east through the Yukon and Northwest Territories, south through British Columbia and through the western half of Alberta. The Alaskan population is estimated at a healthy 30,000 individuals. In the lower 48 states, they are repopulating slowly, but steadily along the Rockies and the western Great Plains.

In Europe, in 2010, there were 14,000 brown bears in ten fragmented populations, from Spain (estimated at only 20–25 animals in the Pyrenees in 2010, in a range shared between Spain, France and Andorra, and some 210 animals in Asturias, Cantabria, Galicia and León, in the Picos de Europa and adjacent areas in 2013 ) in the west, to Russia in the east, and from Sweden and Finland in the north to Romania (5000–6000), Bulgaria (900–1200), Slovakia (with about 600–800 animals), Slovenia (500–700 animals) and Greece (with Karamanlidis et al. 2015 estimating >450 animals) in the south. In Asia, brown bears are found primarily throughout Russia, thence more spottily southwest to parts of the Middle East, including the Eastern Black Sea Region, Turkey that has 5432 individuals of brown bear, to as far south as southwestern Iran, and to the southeast in Northeast China. Brown bears are also found in Western China, Kyrgyzstan, North Korea, Pakistan, Afghanistan and India. A population of brown bear can be found on the Japanese island of Hokkaidō, which holds the largest number of non-Russian brown bears in eastern Asia with about 2,000–3,000 animals.

This species inhabits the broadest range of habitats of any living bear species. They seem to have no altitudinal preferences and have been recorded from sea level to an elevation of 5000 m in the Himalayas. In most of their range, brown bears seem to prefer semiopen country, with a scattering of vegetation that can allow them a resting spot during the day. However, they have been recorded as inhabiting every variety of northern temperate forest known to occur.

Conservation status
While the brown bear's range has shrunk and it has faced local extinctions, it remains listed as a least-concern species by the IUCN, with a total population of approximately 200,000. , this and the American black bear are the only bear species not classified as threatened by the IUCN. However, the California grizzly bear, Ungava brown bear, Atlas bear and Mexican grizzly bear, as well as brown bear populations in the Pacific Northwest, were hunted to extinction in the 19th and early 20th centuries and many of the southern Asian subspecies are highly endangered. The Syrian brown bear (U. a. syriacus) is very rare and it has been extirpated from more than half of its historic range. One of the smallest-bodied subspecies, the Himalayan brown bear (U. a. isabellinus), is critically endangered, occupying only 2% of its former range and threatened by uncontrolled poaching for its body parts. The Marsican brown bear in central Italy is believed to have a population of just 50 bears.

An action plan in 2000 aimed to conserve brown bears in Europe by mitigating human–wildlife conflict, educating farm owners on sustainable practices and preserving/expanding remaining forests. Compensations were given to people who suffered losses in livestock, food supplies or shelters. Growing populations have been recorded in some countries, such as Sweden, where an increase of 1.5% per annum occurred between the 1940s and 1990s. Brown bears in Central Asia are primarily threatened by climate change. Conservationists plan on building wildlife corridors to promote easy access from one brown bear population to another. In Himalayan Nepal, farmers may kill brown bears in revenge for livestock predation.

The smallest populations are most vulnerable to habitat loss and fragmentation. Whereas, the largest are primarily threatened by overhunting. The use of land for agriculture may negatively effect brown bears. Roads and railway tracks are particularly dangerous, as in coming vehicles may collide with bears. Poaching has been cited as another mortality factor. A 3-year survey in the Russian Far East detected the illegal shipping of brown bear cholecyst to Southeast Asian countries. The purpose and motive behind the trade is unknown.

Behavior and life history
Brown bears are generally classified as nocturnal. However, activity appears to peak in the morning and early evening. Activity can occur at any time of night or day; bears that dwell in areas with more extensive human contact are more likely to be fully nocturnal. Furthermore, yearling and newly independent bears are more likely to be active diurnally and many adult bears in low-disturbance areas are largely crepuscular. In summer through autumn, a brown bear can double its weight from the spring, gaining up to 180 kg of fat, on which it relies to make it through winter, when it becomes lethargic. Although they are not full hibernators and can be woken easily, both sexes like to den in a protected spot during the winter months. Hibernation dens may consist of any spot that provides cover from the elements and that can accommodate their bodies, such as a cave, crevice, cavernous tree roots, or hollow logs.

Brown bears have one of the largest brains of any extant carnivoran relative to their body size and have been shown to engage in tool use, which requires advanced cognitive abilities. This species is mostly solitary, although bears may gather in large numbers at major food sources (e.g., open garbage dumps or rivers holding spawning salmon) and form social hierarchies based on age and size. Adult male bears are particularly aggressive and are avoided by adolescent and subadult males, both at concentrated feeding opportunities and chance encounters. Females with cubs rival adult males in aggression and are much more intolerant of other bears than single females. Young adolescent males tend to be least aggressive and have been observed in nonantagonistic interactions with each other. Dominance between bears is asserted by making a frontal orientation, showing off canines, muzzle twisting and neck stretching to which a subordinate will respond with a lateral orientation, by turning away and dropping the head and by sitting or lying down. During combat, bears use their paws to strike their opponents in the chest or shoulders and bite the head or neck.

Communication
Several different facial expressions have been documented in brown bears. The "relaxed-face" is made in everyday activities and has the ears pointed to the sides and the mouth closed or slackly open. During social play, bears make "relaxed open-mouth face" in which the mouth is open, with a curled upper lip and hanging lower lip, and the ears alert and shifting. When looking at another animal at a distance, the bear makes an "alert face" as the ears are cocked and alert, the eyes wide open but the mouth is closed or only open slightly. The "tense closed mouth face" is made with the ears laid back and the mouth closed and occurs when the bear feels threatened. When approached by another individual, the animal makes a "puckered-lip face" with a protruding upper lip and ears which go from cocked and alert when at a certain distance to laid back when closer or when retreating. The "jaw gape face" consists of an open mouth with visible lower canines and hanging lips while the "biting face" is similar to the "relaxed open-mouth face" except the ears are flattened and the eyes are wide enough to expose the sclera. Both the "jaw gape face" and the "biting face" are made in aggression and bears switch between them.

Brown bears also produce various vocalizations. Huffing occurs when the animal is tense while woofing is made when alarmed. Both sounds are produced by exhalations though huffing is harsher and is made continuously (two per second). Growls and roars are made in aggression. Growling is "harsh" and "guttural" and can range from a simple grrr to a rumble. A rumbling growl can escalate into a roar when the bear is charging. Roaring is described as "thunderous" and can travel 2 km. Mothers and cubs wanting physical contact will bawl, which is heard as waugh!, waugh!.

Home ranges
Brown bears usually occur over vast home ranges; however, they are not highly territorial. Several adult bears roam freely over the same vicinity without issue, unless rights to a fertile female or food sources are being contested. Despite their lack of traditional territorial behavior, adult males seem to have a "personal zone" in which other bears are not tolerated if they are seen. Males always wander further than females, due to both increasing access to females and food sources, while females are advantaged by smaller territories in part since it decreases the likelihood of encounters with male bears who may endanger their cubs.

In areas where food is abundant, such as coastal Alaska, home ranges for females and males are up to 24 km2 and 89 km2, respectively. Similarly, in British Columbia, bears of the two sexes travel relatively compact home ranges of 115 and 318 km2. In Yellowstone National Park, home ranges for females are up to 281 km2 and up to 874 km2 for males. In Romania, the largest home range was recorded for adult males (3,143 km2). In the central Arctic of Canada, where food sources are quite sparse, home ranges range up to 2434 km2 in females and 8171 km2 in males.

Reproduction
The mating season occurs from mid-May to early July, shifting later the further north the bears are found. Being serially monogamous, brown bears remain with the same mate from a couple of days to a couple of weeks. Outside of this narrow time frame, adult male and female brown bears show no sexual interest in each other. Females mature sexually between the ages of four and eight; the mean age at sexually maturity is 5.2–5.5 years. Males first mate about a year later, when they are large and strong enough to successfully compete with other males for mating rights. Males will try to mate with as many females as they can; usually a successful one mates with two females in a span of one to three weeks. The adult female brown bear is similarly promiscuous, mating with up to four, sometimes even eight, males while in heat and potentially breeding with two in a single day. Females come into oestrus every three to four years, with a full range of 2.4 to 5.7 years. The urine markings of a female in oestrus can attract several males via scent. Dominant males may try to sequester a female for her entire oestrus period of approximately two weeks, but usually are unable to retain her for the entire time. Copulation is vigorous and prolonged and can last up to an hour, although the mean time is 23–24 minutes.

Males take no part in raising cubs – parenting is left entirely to the females. Through the process of delayed implantation, a female's fertilized egg divides and floats freely in the uterus for six months. During winter dormancy, the fetus attaches to the uterine wall. The cubs are born eight weeks later while the mother sleeps. If the mother does not gain enough weight to survive through the winter while gestating, the embryo does not implant and is reabsorbed into the body. There have been cases of brown bears with as many as six cubs, although the average litter size is one to three; litters of more than four are uncommon. There are records of females sometimes adopting stray cubs or even trading or kidnapping cubs when they emerge from hibernation (a larger female may claim cubs from a smaller one). Older and larger females within a population tend to give birth to larger litters. The size of a litter also depends on factors such as geographic location and food supply. At birth, cubs are blind, toothless and hairless and may weigh 350 to 510 g. They feed on their mother's milk until spring or early summer, depending on climate conditions. At this time, the cubs weigh 7 to 9 kg and have developed enough to follow and forage for solid food with their mother over long distances.

The cubs are fully dependent on the mother and a close bond is formed. During the dependency stage, the cubs learn (rather than inherit as instincts from birth) survival techniques, such as which foods have the highest nutritional value and where to obtain them; how to hunt, fish and defend themselves; and where to den. Increased brain size in large carnivores has been positively linked to whether a given species is solitary, as is the brown bear, or raises their offspring communally, thus female brown bears have relatively large, well-developed brains, presumably key in teaching behavior. The cubs learn by following and imitating their mother's actions during the period they are with her. Cubs remain with their mother for an average of 2.5 years in North America, and gain independence from as early as 1.5 years of age to as late as 4.5 years. The stage at which independence is attained may generally be earlier in some parts of Eurasia, as the latest date which mother and cubs were together was 2.3 years, most families separated in under two years in a study from Hokkaido and in Sweden most cubs on their own were still yearlings. Brown bears practice infanticide, as an adult male bear may kill the cubs of another. When an adult male brown bear kills a cub, it is usually because he is trying to bring the female into oestrus, as she will enter that state within two to four days after the death of her cubs. Cubs may flee up a tree when they see a strange male bear approaching. The mother often successfully defends them, even though the male may be twice as heavy as her. However, females have been known to die in such confrontations.

Dietary habits
The brown bear is one of the most omnivorous animals in the world and has been recorded as consuming the greatest variety of foods of any bear. Despite their reputation, most brown bears are not highly carnivorous, as they derive up to 90% of their dietary food energy from vegetable matter. They often feed on a variety of plant life, including berries, grasses, flowers, acorns and pine cones, as well as fungi such as mushrooms. Among all bears, brown bears are uniquely equipped to dig for tough foods such as roots, bulbs and shoots. They use their long, strong claws to dig out earth to reach the roots and their powerful jaws to bite through them. In spring, winter-provided carrion, grasses, shoots, sedges, moss and forbs are the dietary mainstays for brown bears internationally. Fruits, including berries, become increasingly important during summer and early autumn. Roots and bulbs become critical in autumn for some inland bear populations if fruit crops are poor.

They will also commonly consume animal matter, which in summer and autumn may regularly be in the form of insects, larvae and grubs, including beehives. Bears in Yellowstone eat an enormous number of moths during the summer, sometimes as many as 40,000 army cutworm moths in a single day, and may derive up to half of their annual food energy from these insects. Brown bears living near coastal regions will regularly eat crabs and clams. In Alaska, bears along the beaches of estuaries regularly dig through the sand for clams. This species may eat birds and their eggs, including almost entirely ground- or rock-nesting species. The diet may be supplemented by rodents or similar smallish mammals, including marmots, ground squirrels, mice, rats, lemmings and voles. With particular regularity, bears in Denali National Park will wait at burrows of Arctic ground squirrels hoping to pick off a few of the 1 kg rodents.

In the Kamchatka peninsula and several parts of coastal Alaska, brown bears feed mostly on spawning salmon, whose nutrition and abundance explain the enormous size of the bears in these areas. The fishing techniques of bears are well-documented. They often congregate around falls when the salmon are forced to breach the water, at which point the bears will try to catch the fish in mid-air (often with their mouths). They will also wade into shallow waters, hoping to pin a slippery salmon with their claws. While they may eat almost all the parts of the fish, bears at the peak of spawning, when there is usually a glut of fish to feed on, may eat only the most nutrious parts of the salmon (including the eggs and head) and then indifferently leave the rest of the carcass to scavengers, which can include red foxes, bald eagles, common ravens and gulls. Despite their normally solitary habits, brown bears will gather rather closely in numbers at good spawning sites. The largest and most powerful males claim the most fruitful fishing spots and bears (especially males) will sometimes fight over the rights to a prime fishing spot. Beyond the regular predation of salmon, most brown bears are not particularly active predators. While perhaps a majority of bears of the species will charge at large prey at one point in their lives and most eat carrion, many predation attempts start with the bear clumsily and half-heartedly pursuing the prey and end with the prey escaping alive. On the other hand, some brown bears are quite self-assured predators who habitually pursue and catch large prey items. Such bears are usually taught how to hunt by their mothers from an early age. Large mammals preyed on can include various ungulate species such as elk, moose, caribou, muskoxen and wild boar. When brown bears attack these large animals, they usually target young or infirm ones, as they are easier to catch. Typically when hunting (especially with young prey), the bear pins its prey to the ground and then immediately tears and eats it alive. It will also bite or swipe some prey to stun it enough to knock it over for consumption. To pick out young or infirm individuals, bears will charge at herds so the slower-moving and more vulnerable individuals will be made apparent. Brown bears may ambush young animals by finding them via scent.

When emerging from hibernation, brown bears, whose broad paws allow them to walk over most ice and snow, may pursue large prey such as moose whose hooves cannot support them on encrusted snow. Similarly, predatory attacks on large prey sometimes occur at riverbeds, when it is more difficult for the prey specimen to run away due to muddy or slippery soil. On rare occasions, while confronting fully-grown, dangerous prey, bears kill them by hitting with their powerful forearms, which can break the necks and backs of large creatures such as adult moose and adult bison. They feed on carrion, and use their size to intimidate other predators, such as wolves, cougars, tigers, and American black bears from their kills. Carrion is especially important in the early spring (when the bears are emerging from hibernation), much of it comprising winter-killed big game. Cannibalism is not unheard of, though predation is not normally believed to be the primary motivation when brown bears attack each other.

When forced to live in close proximity with humans and their domesticated animals, bears may potentially predate any type of domestic animal. Among these, domestic cattle are sometimes exploited as prey. Cattle are bitten on the neck, back or head and then the abdominal cavity is opened for eating. Plants and fruit farmed by humans are readily consumed as well, including corn, wheat, sorghum, melons and any form of berries. They may feed on domestic bee yards, readily consuming both honey and the brood (grubs and pupae) of the honey bee colony. Human foods and trash are eaten when possible. When an open garbage dump was kept in Yellowstone, brown bears were one of the most voracious and regular scavengers. The dump was closed after both brown and American black bears came to associate humans with food and lost their natural fear of them.

Interspecific predatory relationships
Adult bears are generally immune to predatory attacks except from large Siberian (Amur) tigers and other bears. Following a decrease of ungulate populations from 1944 to 1959, 32 cases of Siberian tigers attacking both Ussuri brown bears (Ursus arctos lasiotus) and Ussuri black bears (U. thibetanus ussuricus) were recorded in the Russian Far East, and hair of bears were found in several tiger scat samples. Tigers attack black bears less often than brown bears, since the brown bears live in more open habitats and are not able to climb trees. In the same time period, four cases of brown bears killing female tigers and young cubs were reported, both in disputes over prey and in self-defense. In rare cases, when Amur tigers prey on brown bears, they usually target young and sub-adult bears, besides small female adults taken outside their dens, generally when lethargic from hibernation. Predation by tigers on denned brown bears was not detected during a study carried between 1993 and 2002. Ussuri brown bears, along with the smaller black bears constitute 2.1% of the Siberian tiger's annual diet, of which 1.4% are brown bears.

Brown bears regularly intimidate wolves to drive them away from their kills. In Yellowstone National Park, bears pirate wolf kills so often, Yellowstone's Wolf Project director Doug Smith wrote, "It's not a matter of if the bears will come calling after a kill, but when." Despite the high animosity between the two species, most confrontations at kill sites or large carcasses end without bloodshed on either side. Though conflict over carcasses is common, on rare occasions, the two predators tolerate each other on the same kill. To date, there is a single recorded case of fully-grown wolves being killed by a grizzly bear. Given the opportunity, however, both species will prey on the other's cubs. In some areas, grizzly bears regularly displace cougars from their kills. Cougars kill small bear cubs on rare occasions, but there was one report of a bear killing a cougar of unknown age and condition between 1993 and 1996.

Brown bears usually dominate other bear species in areas where they coexist. Due to their smaller size, American black bears are at a competitive disadvantage to grizzly bears in open, unforested areas. Although displacement of black bears by grizzly bears has been documented, actual interspecific killing of black bears by grizzlies has only occasionally been reported. Confrontation is mostly avoided due to the black bear's diurnal habits and preference for heavily forested areas, as opposed to the grizzly's largely nocturnal habits and preference for open spaces. Brown bears may also kill Asian black bears, though the latter species probably largely avoids conflicts with the brown bear, due to similar habits and habitat preferences to the American black species. As of the 21st century, there has been an increase in interactions between brown bears and polar bears, theorized to be caused by climate change. Brown and grizzly bears have been seen moving increasingly northward into territories formerly claimed by polar bears. They tend to dominate polar bears in disputes over carcasses, and dead polar bear cubs have been found in brown bear dens.

Longevity and mortality
The brown bear has a naturally long life. Wild females have been observed reproducing at 28 years, which is the oldest known age for reproduction of any ursid in the wild. The peak reproductive age for females ranges from four to 20 years old. The lifespan of both sexes within minimally hunted populations is estimated at an average of 25 years. The oldest recorded wild individual was nearly 37 years old. In captivity, the oldest recorded female was around 40 years old, while males have been verified to live up to 47 years.

While male bears potentially live longer in captivity, female grizzly bears have a greater annual survival rate than males within wild populations per a study done in the Greater Yellowstone Ecosystem. Annual mortality for bears of any age is estimated at 10% in most protected areas. Around 13% to 44% of cubs die within their first year. Beyond predation by large predators including wolves, Siberian tigers and other brown bears, starvation and accidents also claim the lives of cubs. Studies have indicated that the most prevalent source of mortality for first-year cubs is malnutrition.

Brown bears are susceptible to parasites such as flukes, ticks, tapeworms, roundworms and biting lice. It is thought that brown bears may catch canine distemper virus (CDV) from other Caniforms like stray dogs and wolves. A captive individual allegedly succumbed to Aujeszky's disease.

Hibernation physiology
A study conducted by the Brown Bear Research Project did a proteomic analysis of the brown bear's blood, organs, and tissues to pinpoint proteins and peptides that either increased or decreased in expression in the winter and summer months. One major finding was that the plasma protein sex hormone-binding globulin (SHBG) increased during the brown bear's hibernation period by 45 times. Although scientists do not yet understand the role of SHBG in maintaining the brown bear's health, some believe these findings could potentially be a factor in preventing human diseases that come from a sedentary life style.

Attacks on humans
Brown bears usually avoid areas where extensive development or urbanization has occurred. They rarely attack on sight and usually avoid people. They are, however, unpredictable in temperament, and may attack if threatened or surprised. Mothers defending cubs are the most prone to attacking, being responsible for 70% of brown bear-caused human fatalities in North America. Attacks tend to result in serious injury and, in some cases, death. Due to the bears' enormous physical strength, a single bite or swipe can be deadly. Violent encounters with brown bears usually last a few minutes, though they can be prolonged if the victims fight back.

A study conducted in 2019 found that 664 bear attacks were reported during a 15-year period (20002015) throughout North America and Eurasia. There were 568 injuries and 95 casualties. Around 10 people a year are killed by brown bears in Russia, more than all the other parts of the brown bear's range combined. In Japan, a large brown bear nicknamed "Kesagake" ("kesa-style slasher") caused the worst brown bear attack in Japanese history at Tomamae, Hokkaidō during numerous encounters during December 1915. It killed seven people and wounded three others before being gunned down after a large-scale beast-hunt. A study by U.S. and Canadian researchers has found bear spray to be more effective at stopping aggressive bear behavior than guns, working in 92% of studied incidents versus 67% for guns.

Bear hunting
Humans have been recorded hunting brown bears for over 10,300–9,300 years. In Europe, between the 17th and 18th centuries, humans sought to control brown bear numbers by awarding those who managed to kill one. This bounty scheme pushed the brown bear population to the brink of extinction before comprehensive protection was offered in the 1900s. Despite this, a 2018 study found hunting to be one of the contributing factors to the drop in brown bear numbers in northern Europe. In some places in Europe, bears are baited into entering traps.

The earliest known case of a European killing a grizzly bear dates back to 1691. Their arrival in western United States led to the extirpation of local brown bear populations in the 19th and early 20th centuries. During the early years of European settlement in North America, bears were usually killed with a spear or lasso rope. The introduction of rifles in the mid-19th century largely facilitated bear hunts, which allowed for an increasing trend. Bears were also pitted into fights against male cattle, often ending with either animal dead. The last two decades of the 19th century saw an increase in bounties. Conflicts with farmers also contributed to its rapid decline. It wasn't until the 1920s that grizzly bears received some type of protection from the US government. Brown bears are legally hunted in some American states, such as Alaska. However, a hunting license is required and killings of females with cubs will result in a prison sentence.

Their meat is sometimes consumed and used in recipes such as dumplings, hams and stews. The Indigenous people of James Bay (Eastern) Cree use their flesh in traditional dishes. In Asia and Romania, the paws are consumed as exotic delectables; brown bear paws have been a prevalent component of traditional Chinese food since 500 BC. The total weight of commercially sold brown bear meat is estimated at 17 tons annually.

In captivity
Bears have been recorded in captivity as early as 1,500 BC. There are more than 700 brown bears in zoos and wildlife parks worldwide. Captive bears are largely lethargic and spend a considerable amount of time doing nothing. When active, captive bears may be subject to repetitive back and forth motion, known widely as pacing. This behavior is most prevalent in bears kept in small, cramped cages often with no natural setting. Pacing is a way of coping with stress that comes with being trapped in unnaturally small spaces. Stereotyped behavior has decreased due to better and larger enclosures being built, and more sustainable management from zoo staff.

They are also exploited as dancing bears. The process begins at an early age. Cubs, for example, are positioned on hot metal plates, causing them to exhibit dancing movements, and at the same time, violin music is running in the background. The process is repeated, resulting in bears being trained to dance when a violin is played. Similarly, brown bears are displayed in tiny enclosures near a restaurant, mainly for the purpose of luring customers. Privately owned bears are usually placed in insufficient environments and often suffer from malnutrition and obesity.

Brown bears have been popular attractions at circuses and other acts since ancient times. Due to their large size and imposing demeanor, the Romans used brown bears in the execution of criminals, and pitted fights between bears and other animals. Gladiators would take on bears, in what was essentially a fight to the death. Such events occurred in amphitheaters housing thousands of spectators. Street performances became popular in Medieval times. Acts included "dancing" and "sleeping on command". From the 1700s to 1800s, traveling circuses would perform in the streets of many European and Asian countries. Such circuses made use of bears that wore special clothing. They were usually run by musicians, and still continue today. Modern circuses began utilizing bears around the second half of the 18th century. Brown bears are said to be the easiest bear species to train. This could be due to their intelligence, unique personalities and exceptional stability. According to a 2009 analysis, the brown bear was the second most exploited circus animal after the tiger.

Culture
Bears have been popular subjects in art, literature, folklore and mythology. The image of the mother bear was prevalent throughout societies in North America and Eurasia, based on the female's devotion and protection of her cubs. Brown bears often figure into the literature of Europe and North America as "cute and cuddly", in particular that which is written for children. "The Brown Bear of Norway" is a Scottish fairy tale telling the adventures of a girl who married a prince magically turned into a bear and who managed to get him back into a human form by the force of her love and after many trials and difficulties. With "Goldilocks and the Three Bears", a story from England, the Three Bears are usually depicted as brown bears. In German-speaking countries, children are often told the fairytale of "Snow White and Rose Red"; the handsome prince in this tale has been transfigured into a brown bear. In the United States, parents often read their preschool age children the book Brown Bear, Brown Bear, What Do You See? to teach them their colors and how they are associated with different animals. Smokey Bear, a famous mascot of U.S. Forest Service since the 1940s, is used to warn and educate people on the dangers of human-caused wildfire.

Brown bears have been extensively featured in the culture of Native Americans, and are considered sacred. To stop a bear's spirit from escaping after it was killed by hunters, the Denaa people severed all 4 of its paws. Some time passed before Denaa were ready to consume its flesh; it was believed that the spirit was overwhelming in fresh kills. People that wore bear claw necklaces were highly respected, mainly due to the bear's reputation of being extremely powerful and fierce. The clattering caused by repeatedly shaking these necklaces were believed to bring forth therapeutic powers. In Haida culture, one legend has it that a marriage between a woman and a grizzly bear commenced in the lineage of Indian people. This is thought to have allowed Haida to thrive in bear country.

There is evidence of prehistoric bear worship, though this is disputed by archaeologists. It is possible that bear worship existed in early Chinese and Ainu cultures. In Ancient Greek mythology, bears were considered similar to humans, mainly due to their ability of standing upright. In many western stories and older fables the portrayed attributes of bears are sluggishness, foolishness and gullibility, which contradicts actual species. For example, bears have been reported tricking hunters by backtracking in the snow. The Romans built small carved figures of bears that were used during burials of infants. The earliest cave paintings of bears occurred in the Paleolithic, with over 100 recorded paintings.

The Russian bear is a common national personification for Russia (as well as the former Soviet Union), despite the country having no officially-designated national animal. The brown bear is Finland's national animal. The grizzly bear is the state animal of Montana. The California golden bear is the state animal of California, despite being extinct. In North America, the brown bear is considered a charismatic megafauna and has long piqued people's interest. The death of Bear 148 at the hands of a trophy hunter in 2017, sparked media outrage and the continued disapproval of trophy hunting. The coat of arms of Madrid depicts a bear reaching up into a madroño or strawberry tree (Arbutus unedo) to eat some of its fruit, whereas the Swiss city of Bern's coat of arms also depicts a bear and the city's name is popularly thought to derive from the German word for bear. The brown bear is depicted on the reverse of the Croatian 5 kuna coin, minted since 1993.

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

title: Brown bear


text:
BCS theory

In physics, the Bardeen–Cooper–Schrieffer (BCS) theory (named after John Bardeen, Leon Cooper, and John Robert Schrieffer) is the first microscopic theory of superconductivity since Heike Kamerlingh Onnes's 1911 discovery. The theory describes superconductivity as a microscopic effect caused by a condensation of Cooper pairs. The theory is also used in nuclear physics to describe the pairing interaction between nucleons in an atomic nucleus.

It was proposed by Bardeen, Cooper, and Schrieffer in 1957; they received the Nobel Prize in Physics for this theory in 1972.

History
Rapid progress in the understanding of superconductivity gained momentum in the mid-1950s. It began with the 1948 paper, "On the Problem of the Molecular Theory of Superconductivity", where Fritz London proposed that the phenomenological London equations may be consequences of the coherence of a quantum state. In 1953, Brian Pippard, motivated by penetration experiments, proposed that this would modify the London equations via a new scale parameter called the coherence length. John Bardeen then argued in the 1955 paper, "Theory of the Meissner Effect in Superconductors", that such a modification naturally occurs in a theory with an energy gap. The key ingredient was Leon Cooper's calculation of the bound states of electrons subject to an attractive force in his 1956 paper, "Bound Electron Pairs in a Degenerate Fermi Gas".

In 1957 Bardeen and Cooper assembled these ingredients and constructed such a theory, the BCS theory, with Robert Schrieffer. The theory was first published in April 1957 in the letter, "Microscopic theory of superconductivity". The demonstration that the phase transition is second order, that it reproduces the Meissner effect and the calculations of specific heats and penetration depths appeared in the December 1957 article, "Theory of superconductivity". They received the Nobel Prize in Physics in 1972 for this theory.

In 1986, high-temperature superconductivity was discovered in La-Ba-Cu-O, at temperatures up to 30 K. Following experiments determined more materials with transition temperatures up to about 130 K, considerably above the previous limit of about 30 K. It is experimentally very well known that the transition temperature strongly depends on pressure. In general, it is believed that BCS theory alone cannot explain this phenomenon and that other effects are in play. These effects are still not yet fully understood; it is possible that they even control superconductivity at low temperatures for some materials.

Overview
At sufficiently low temperatures, electrons near the Fermi surface become unstable against the formation of Cooper pairs. Cooper showed such binding will occur in the presence of an attractive potential, no matter how weak. In conventional superconductors, an attraction is generally attributed to an electron-lattice interaction. The BCS theory, however, requires only that the potential be attractive, regardless of its origin. In the BCS framework, superconductivity is a macroscopic effect which results from the condensation of Cooper pairs. These have some bosonic properties, and bosons, at sufficiently low temperature, can form a large Bose–Einstein condensate. Superconductivity was simultaneously explained by Nikolay Bogolyubov, by means of the Bogoliubov transformations.

In many superconductors, the attractive interaction between electrons (necessary for pairing) is brought about indirectly by the interaction between the electrons and the vibrating crystal lattice (the phonons). Roughly speaking the picture is the following:

"An electron moving through a conductor will attract nearby positive charges in the lattice. This deformation of the lattice causes another electron, with opposite spin, to move into the region of higher positive charge density. The two electrons then become correlated. Because there are a lot of such electron pairs in a superconductor, these pairs overlap very strongly and form a highly collective condensate. In this 'condensed' state, the breaking of one pair will change the energy of the entire condensate - not just a single electron, or a single pair. Thus, the energy required to break any single pair is related to the energy required to break all of the pairs (or more than just two electrons). Because the pairing increases this energy barrier, kicks from oscillating atoms in the conductor (which are small at sufficiently low temperatures) are not enough to affect the condensate as a whole, or any individual 'member pair' within the condensate. Thus the electrons stay paired together and resist all kicks, and the electron flow as a whole (the current through the superconductor) will not experience resistance. Thus, the collective behavior of the condensate is a crucial ingredient necessary for superconductivity."

Details
BCS theory starts from the assumption that there is some attraction between electrons, which can overcome the Coulomb repulsion. In most materials (in low temperature superconductors), this attraction is brought about indirectly by the coupling of electrons to the crystal lattice (as explained above). However, the results of BCS theory do not depend on the origin of the attractive interaction. For instance, Cooper pairs have been observed in ultracold gases of fermions where a homogeneous magnetic field has been tuned to their Feshbach resonance. The original results of BCS (discussed below) described an s-wave superconducting state, which is the rule among low-temperature superconductors but is not realized in many unconventional superconductors such as the d-wave high-temperature superconductors.

Extensions of BCS theory exist to describe these other cases, although they are insufficient to completely describe the observed features of high-temperature superconductivity.

BCS is able to give an approximation for the quantum-mechanical many-body state of the system of (attractively interacting) electrons inside the metal. This state is now known as the BCS state. In the normal state of a metal, electrons move independently, whereas in the BCS state, they are bound into Cooper pairs by the attractive interaction. The BCS formalism is based on the reduced potential for the electrons' attraction. Within this potential, a variational ansatz for the wave function is proposed. This ansatz was later shown to be exact in the dense limit of pairs. Note that the continuous crossover between the dilute and dense regimes of attracting pairs of fermions is still an open problem, which now attracts a lot of attention within the field of ultracold gases.

Underlying evidence
The hyperphysics website pages at Georgia State University summarize some key background to BCS theory as follows:

 * Evidence of a band gap at the Fermi level (described as "a key piece in the puzzle")
 * the existence of a critical temperature and critical magnetic field implied a band gap, and suggested a phase transition, but single electrons are forbidden from condensing to the same energy level by the Pauli exclusion principle. The site comments that "a drastic change in conductivity demanded a drastic change in electron behavior". Conceivably, pairs of electrons might perhaps act like bosons instead, which are bound by different condensate rules and do not have the same limitation.

 * Isotope effect on the critical temperature, suggesting lattice interactions
 * The Debye frequency of phonons in a lattice is proportional to the inverse of the square root of the mass of lattice ions. It was shown that the superconducting transition temperature of mercury indeed showed the same dependence, by substituting the most abundant natural mercury isotope, 202Hg, with a different isotope, 198Hg.

 * An exponential rise in heat capacity near the critical temperature for some superconductors
 * An exponential increase in heat capacity near the critical temperature also suggests an energy bandgap for the superconducting material. As superconducting vanadium is warmed toward its critical temperature, its heat capacity increases greatly in a very few degrees; this suggests an energy gap being bridged by thermal energy.

 * The lessening of the measured energy gap towards the critical temperature
 * This suggests a type of situation where some kind of binding energy exists but it is gradually weakened as the temperature increases toward the critical temperature. A binding energy suggests two or more particles or other entities that are bound together in the superconducting state. This helped to support the idea of bound particles – specifically electron pairs – and together with the above helped to paint a general picture of paired electrons and their lattice interactions.

Implications
BCS derived several important theoretical predictions that are independent of the details of the interaction, since the quantitative predictions mentioned below hold for any sufficiently weak attraction between the electrons and this last condition is fulfilled for many low temperature superconductors - the so-called weak-coupling case. These have been confirmed in numerous experiments:
 * The electrons are bound into Cooper pairs, and these pairs are correlated due to the Pauli exclusion principle for the electrons, from which they are constructed. Therefore, in order to break a pair, one has to change energies of all other pairs. This means there is an energy gap for single-particle excitation, unlike in the normal metal (where the state of an electron can be changed by adding an arbitrarily small amount of energy). This energy gap is highest at low temperatures but vanishes at the transition temperature when superconductivity ceases to exist. The BCS theory gives an expression that shows how the gap grows with the strength of the attractive interaction and the (normal phase) single particle density of states at the Fermi level. Furthermore, it describes how the density of states is changed on entering the superconducting state, where there are no electronic states any more at the Fermi level. The energy gap is most directly observed in tunneling experiments and in reflection of microwaves from superconductors.
 * BCS theory predicts the dependence of the value of the energy gap Δ at temperature T on the critical temperature Tc. The ratio between the value of the energy gap at zero temperature and the value of the superconducting transition temperature (expressed in energy units) takes the universal value $$\Delta(T=0) = 1.764 \, k_{\rm B}T_{\rm c},$$ independent of material. Near the critical temperature the relation asymptotes to $$\Delta(T \to T_{\rm c})\approx 3.06 \, k_{\rm B}T_{\rm c}\sqrt{1-(T/T_{\rm c})}$$ which is of the form suggested the previous year by M. J. Buckingham based on the fact that the superconducting phase transition is second order, that the superconducting phase has a mass gap and on Blevins, Gordy and Fairbank's experimental results the previous year on the absorption of millimeter waves by superconducting tin.
 * Due to the energy gap, the specific heat of the superconductor is suppressed strongly (exponentially) at low temperatures, there being no thermal excitations left. However, before reaching the transition temperature, the specific heat of the superconductor becomes even higher than that of the normal conductor (measured immediately above the transition) and the ratio of these two values is found to be universally given by 2.5.
 * BCS theory correctly predicts the Meissner effect, i.e. the expulsion of a magnetic field from the superconductor and the variation of the penetration depth (the extent of the screening currents flowing below the metal's surface) with temperature.
 * It also describes the variation of the critical magnetic field (above which the superconductor can no longer expel the field but becomes normal conducting) with temperature. BCS theory relates the value of the critical field at zero temperature to the value of the transition temperature and the density of states at the Fermi level.
 * In its simplest form, BCS gives the superconducting transition temperature Tc in terms of the electron-phonon coupling potential V and the Debye cutoff energy ED: $$k_{\rm B}\,T_{\rm c} = 1.134E_{\rm D}\,{e^{-1/N(0)\,V}},$$ where N(0) is the electronic density of states at the Fermi level. For more details, see Cooper pairs.
 * The BCS theory reproduces the isotope effect, which is the experimental observation that for a given superconducting material, the critical temperature is inversely proportional to the square-root of the mass of the isotope used in the material. The isotope effect was reported by two groups on 24 March 1950, who discovered it independently working with different mercury isotopes, although a few days before publication they learned of each other's results at the ONR conference in Atlanta. The two groups are Emanuel Maxwell, and C. A. Reynolds, B. Serin, W. H. Wright, and L. B. Nesbitt. The choice of isotope ordinarily has little effect on the electrical properties of a material, but does affect the frequency of lattice vibrations. This effect suggests that superconductivity is related to vibrations of the lattice. This is incorporated into BCS theory, where lattice vibrations yield the binding energy of electrons in a Cooper pair.
 * Little–Parks experiment - One of the first indications to the importance of the Cooper-pairing principle.

title: BCS theory


text:
Biathlon

The biathlon is a winter sport that combines cross-country skiing and rifle shooting. It is treated as a race, with contestants skiing through a cross-country trail whose distance is divided into shooting rounds. The shooting rounds are not timed per se, but depending on the competition, missed shots result in extra distance or time being added to the contestant's total.

History
According to Encyclopædia Britannica, the biathlon "is rooted in the skiing traditions of Scandinavia, where early inhabitants revered the Norse god Ullr as both the ski god and the hunting god." In modern times, the activity that developed into this sport was an exercise for Norwegians as alternative training for the military. Norwegian skiing regiments organized military skiing contests in the 18th century, divided into four classes: shooting at mark while skiing at top speed, downhill race among trees, downhill race on big hills without falling, and a long race on flat ground while carrying a rifle and military pack. In modern terminology, these military contests included downhill, slalom, biathlon, and cross-country skiing. One of the world's first known ski clubs, Trysil Skytte- og Skiløberforening (the Trysil Rifle and Ski Club), was formed in Norway in 1861 to promote national defense at the local level. 20th century variants include Forsvarsrennet (the military contest), a 17 km cross-country race with shooting, and the military cross-country race at 30 km including marksmanship.

The modern biathlon is a civilian variant of the old military combined exercise. In Norway, the biathlon was until 1984 a branch of Det frivillige Skyttervesen, an organization set up by the government to promote civilian marksmanship in support of national defence. In Norwegian, the biathlon is called skiskyting (literally ski shooting). In Norway, there are still separate contests in skifeltskyting, a cross-country race at 12 km with large-caliber rifle shooting at various targets with unknown range.

Called military patrol, the combination of skiing and shooting was contested at the Winter Olympic Games in 1924 and then demonstrated in 1928, 1936, and 1948, during which time Norway and Finland were strong competitors. In 1948, the sport was reorganized under the Union Internationale de Pentathlon Moderne et Biathlon and became re-accepted as an Olympic sport in 1955, with widespread popularity within the Soviet and Swedish winter sport circuits.

The first Biathlon World Championship was held in 1958 in Austria, and in 1960 the sport was finally included in the Olympic Games. At Albertville in 1992, women were first allowed in the Olympic biathlon. The pursuit format was added for the 2002 Salt Lake City Winter Olympics, and the IBU added mixed relay as a format for the 2006 Olympics.

The competitions from 1958 to 1965 used high-power centrefire cartridges, such as the .30-06 Springfield and the 7.62×51mm NATO, before the .22 Long Rifle rimfire cartridge was standardized in 1978. The ammunition was carried in a belt worn around the competitor's waist. The sole event was the men's 20 km individual, encompassing four separate ranges and firing distances of 100 m, 150 m, 200 m, and 250 m. The target distance was reduced to 150 m with the addition of the relay in 1966. The shooting range was further reduced to 50 m in 1978 with the mechanical self-indicating targets making their debut at the 1980 Winter Olympics in Lake Placid. For the 2018–2019 season, fully electronic targets were approved as an alternative to paper or mechanical steel targets for IBU events.

Governing body
In 1948, the International Modern Pentathlon Union (UIPM) was founded to standardize the rules for the modern pentathlon and from 1953 also biathlon. In July 1993, the biathlon branch of the UIPMB created the International Biathlon Union (IBU), which officially separated from the UIPMB in 1998.

Presidents of the UIPMB/IBU:
 * 1947–1949: Tom Wiborn (Sweden)
 * 1949–1960: Gustaf Dyrssen (Sweden)
 * 1960–1988: Sven Thofelt (Sweden)
 * 1988–1992: Igor Novikov (USSR/Russia)
 * 1992–2018: Anders Besseberg (Norway)
 * Since 2018: Olle Dahlin (Sweden)

Championships
The following articles list major international biathlon events and medalists. Unlike the Olympics and World Championships (BWCH), the World Cup (BWC) is an entire winter season of (mostly) weekly races, where the medalists are those with the highest sums of World Cup points at the end of the season.
 * Biathlon at the Winter Olympics
 * Biathlon World Championships
 * Biathlon World Cup
 * Biathlon European Championships
 * IBU Cup
 * Biathlon Junior World Championships
 * Biathlon at the Winter Universiade

Rules and equipment
The complete rules of the biathlon are given in the official IBU rule books.

Basic concepts
A biathlon competition consists of a race in which contestants ski through a cross-country trail system whose total distance is divided into either two or four shooting rounds, half in the prone position, the other half standing. Depending on the shooting performance, extra distance or time is added to the contestant's total skiing distance/time. The contestant with the shortest total time wins.

For each shooting round, the biathlete must hit five targets or receive a penalty for each missed target, which varies according to the competition rules as follows:

 * Skiing around a 150 m penalty loop—typically taking 20–30 seconds for elite biathletes to complete, depending on weather and snow conditions.
 * Adding one minute to the skier's total time.
 * Use of an extra cartridge (placed at the shooting range) to hit the target; only three such extras are available for each round, and a penalty loop must be done for each target left standing.

In order to keep track of the contestants' progress and relative standing throughout a race, split times (intermediate times) are taken at several points along the skiing track and upon finishing each shooting round. The large display screens commonly set up at biathlon arenas, as well as the information graphics shown as part of the TV picture, will typically list the split time of the fastest contestant at each intermediate point and the times and time differences to the closest runners-up.

Skiing details
In the Olympics, all cross-country skiing techniques are permitted in the biathlon, allowing the use of skate skiing, which is overwhelmingly the choice of competitors. The minimum ski length is the height of the skier minus 4 cm. The rifle has to be carried by the skier during the race at all times.

Shooting details

The biathlete carries a small-bore rifle, which must weigh at least 3.5 kg, excluding ammunition and magazines. The rifles use .22 LR ammunition and are bolt action or Fortner (straight-pull bolt) action. Each rifle holds 4 magazines with 5 rounds each. Additional rounds can be kept on the stock of the rifle for a relay race.

The target range shooting distance is 50 m. There are five circular shooting targets to be hit in each shooting round. When shooting in the prone position, the target diameter is 45 mm; when shooting in the standing position, the target diameter is 115 mm. This translates to angular target sizes of 0.9 and 2.3 mrad respectively. On all modern biathlon ranges, the targets are self-indicating, in that they flip from black to white when hit, giving the biathlete, as well as the spectators, instant visual feedback for each shot fired.

Ear protection is not required during biathlon shooting as the ammunition used is usually subsonic. An eyecup (blinder) is an optional feature of biathlon rifles.

Individual
The 20 km individual race [15 km for women] is the oldest biathlon event; the distance is skied over five laps. The biathlete shoots four times at any shooting lane (lanes 1–15 are in prone, while lanes 16–30 are for standing), in the order of prone, standing, prone, standing, totaling 20 targets. For each missed target, a fixed penalty time, usually one minute, is added to the skiing time of the biathlete. Competitors' starts are staggered, normally by 30 seconds.

A variation of the standard individual race, called short individual, was introduced during the 2018–19 Biathlon IBU Cup. The races are 15 km for men and 12.5 km for women, and for each missed target, 45 seconds will be added to the skiing time.

Sprint
The sprint is 10 km for men & 7.5 km for women; the distance is skied over three laps. The biathlete shoots twice at any shooting lane, once prone (usually lanes 1–15) and once standing (lanes 16–30), for a total of 10 shots. For each miss, a penalty loop of 150 m must be skied before continuing the race. As in the individual competition, the biathletes start in intervals.

Super Sprint
Introduced at the 2017–18 Biathlon IBU Cup, the Super Sprint is a shorter version of the sprint race. Unlike the traditional sprint race, the Super Sprint is divided into two segments – qualification and final. The qualification is done like the traditional sprint, but on a 1.5 km lap with a total length of 4.5 km. Only the top 30 competitors qualify for the final, in which all competitors start simultaneously and do five laps on the same course (like in mass start) with a total race length of 4 km. During the final, the competitors have three spare rounds should they miss a target (like in relay race). However, if not all targets are cleared during shooting instead of going on the penalty loop, the biathlete is disqualified from the race.

Changes were made for the following season with the course now being 1 km (0.2 km increase) meaning that the qualification race length will become 3 km, while the final race becomes 5 km in length. Also the number of spare rounds was decreased from three to one.

Pursuit

In a pursuit, biathletes' starts are separated by their time differences from a previous race, most commonly a sprint. The contestant crossing the finish line first is the winner. The distance is 12.5 km for men and 10 km for women, skied over five laps; there are four shooting bouts (two prone, two standing, in that order) and each miss means a penalty loop of 150 m. To prevent awkward or dangerous crowding of the skiing loops and overcapacity at the shooting range, World Cup Pursuits are held with only the 60 top-ranking biathletes after the preceding race. The biathletes shoot on a first-come, first-served basis at the lane corresponding to the position they arrived for all shooting bouts. If the pursuit follows an individual biathlon race, the lag behind the winner is halved.

Mass start
In the mass start, all biathletes start at the same time, and the first across the finish line wins. In this 15 km for men or 12.5 km for women competition, the distance is skied over five laps; there are four bouts of shooting (two prone, two standing, in that order), with the first shooting bout being at the lane corresponding to the competitor's bib number (bib #10 shoots at lane #10 regardless of position in race), with the rest of the shooting bouts being on a first-come, first-served basis (if a competitor arrives at the lane in fifth place, they shoot at lane 5). As in sprint and pursuit, competitors must ski one 150 m penalty loop for each miss. Here again, to avoid unwanted congestion, World Cup Mass starts are held with only the 30 top ranking athletes on the start line (half that of the Pursuit as here all contestants start simultaneously).

Mass start 60
Starting in the 2018/2019 season, the Mass Start 60 became part of the International Biathlon Union (IBU) competition formats. The Mass Start with 60 starters does not replace the current Mass Start with 30 starters.

Everyone skis the first lap together, but only the first 30 stop to shoot, and the second 30 keep skiing. At the end of the second lap, the second 30 stop to shoot, and the first 30 continue to ski. After the first two shoots are over (everyone's first prone), the race continues like a typical race, and all competitors shoot remaining prone, and two stands together. Or more simply:

Bib 1–30 = lap, shoot1, lap, lap, shoot2, lap, shoot3, lap, shoot4, lap

Bib 31–60 = lap, lap, shoot1, lap, shoot2, lap, shoot3, lap, shoot4, lap

Relay
The relay teams consist of four biathletes, who each ski 7.5 km (men) or 6 km (women), each leg skied over three laps, with two shooting rounds; one prone, one standing. For every round of five targets, there are eight bullets available. However, the last three can only be single-loaded manually one at a time from spare round holders or bullets deposited by the competitor into trays or onto the mat at the firing line. If there are still standing targets after eight bullets, one 150 m (490 ft) penalty loop must be taken for each missed target remaining. The first-leg participants all start simultaneously, and as in cross-country skiing relays, every athlete of a team must touch the team's next-leg participant to perform a valid changeover. On the first shooting stage of the first leg, the participant must shoot in the lane corresponding to their bib number (bib #10 shoots at lane #10 regardless of their position in the race), then for the remainder of the relay, the relay team shoots on a first-come, first-served basis (arrive at the range in fifth place, shoot at lane 5).

Mixed relay
The mixed relay is similar to the ordinary relay, but the teams are composed of two women and two men. From its first instance at the world championships in 2005 until the end of the 2017 season, the first two legs were always run by the women, followed by the men on legs 3 and 4. Since the 2018 season however, the race can be started by either the men or women. Additionally, throughout most the event's history, the women's legs have been 6 km and the men's legs 7.5 km as in ordinary relay competitions. However, since the 2019 season the event has all four legs being either 6 km or 7.5 km. This event was added to the Olympics starting in 2014.

Single mixed relay
In 2015, the single mixed relay was introduced to the Biathlon World Cup by the IBU. The event is run on a 1.5 km track with a 75 m penalty loop, and each team consists of a female and a male runner. The race is divided into four legs, with the first three being 3 km or 2 laps and the final leg being 4.5 km or 3 laps, totalling 13.5 km. After each leg, the runners exchange so that each runner completes two legs. Specific to this format, the exchange happens immediately after the last shooting of each leg without skiing an additional lap (as is usually the case). The race can be started by either the female or male member of the relay, with the finishing member performing an extra lap. This event was added to the world championships in 2019.

Team (obsolete)
A team consists of four biathletes, but unlike the relay competition, all team members start at the same time. Two athletes must shoot in the prone shooting round, the other two in the standing round. In case of a miss, the two non-shooting biathletes must ski a penalty loop of 150 m (490 ft). The skiers must enter the shooting area together and must also finish within 15 seconds of each other; otherwise, a time penalty of one minute is added to the total time. Since 2004, this race format has been obsolete at the World Cup level.

Broadcasting
Biathlon events are broadcast most regularly where the sport enjoys its greatest popularity, namely Germany (ARD, ZDF), Austria (ORF), Norway (NRK), France (L'Équipe 21), Finland (YLE), Estonia (ETV), Latvia (LTV), Lithuania (LRT), Croatia (HRT), Poland (Polsat), Ukraine (UA:PBC), Sweden (SVT), Russia (Match TV, Channel One), Belarus (TVR), Slovenia (RTV), Bosnia and Herzegovina (BHRT), Bulgaria (BNT), and South Korea (KBS); it is broadcast on European-wide Eurosport, which also broadcasts to the Asia-Pacific region. World Cup races are streamed via the IBU website.

The broadcast distribution being one indicator, the constellation of a sport's main sponsors usually gives a similar, and correlated, indication of popularity: for biathlon, these are the Germany-based companies BMW (cars), Erdinger (beer), Viessmann (boilers and other heating systems) and DKB (banking).

Biathlon records and statistics
The IBU maintains biathlon records, rules, news, videos, and statistics for many years back, all of which are available at its web site.

National Associations

 * Belarusian Biathlon Union
 * Russian Biathlon Union
 * Russian Biathlon Union
 * Biathlon Canada
 * U.S. Biathlon Association
 * Biathlon Russia
 * Biathlon Ukraine
 * Biathlon Ukraine
 * BiathlonFrance.com

title: Biathlon


text:
Bubble and squeak

Bubble and squeak is a British dish made from cooked potatoes and cabbage, mixed together and fried. The food writer Howard Hillman classes it as one of the "great peasant dishes of the world". The dish has been known since at least the 18th century, and in its early versions it contained cooked beef; by the mid-20th century the two vegetables had become the principal ingredients.

History
The name of the dish, according to the Oxford English Dictionary (OED), alludes to the sounds made by the ingredients when being fried. The first recorded use of the name listed in the OED dates from 1762; The St James's Chronicle, recording the dishes served at a banquet, included "Bubble and Squeak, garnish'd with Eddowes Cow Bumbo, and Tongue". A correspondent in The Public Advertiser two years later reported making "a very hearty Meal on fried Beef and Cabbage; though I could not have touched it had my Wife recommended it to me under the fashionable Appellation of Bubble and Squeak". In 1791 another London paper recorded the quarterly meeting of the Bubble and Squeak Society at Smithfield.

The dish as it is made in modern times differs considerably from its first recorded versions, in which cooked beef was the main ingredient and potatoes did not feature. The earliest-known recipe is in Maria Rundell's A New System of Domestic Cookery, published in 1806. It consists wholly of cabbage and rare roast beef, seasoned and fried. This method is followed by William Kitchiner in his book Apicius Redivivus, or The Cook's Oracle (1817); in later editions he adds a couplet at the top of his recipe: When 'midst the frying Pan in accents savage, The Beef, so surly, quarrels with the Cabbage. Mrs Beeton's recipe in her Book of Household Management (1861) similarly combines cooked beef with cabbage (and, in her recipe, onions) but no potato. An 1848 recipe from the US is similar, but adds chopped carrots. In all of these, the meat and vegetables are served next to each other, and not mixed together.

In 1872, a Lancashire newspaper offered a recipe for "delicious bubble and squeak", consisting of thinly-sliced beef fried with cabbage and carrot, but not potatoes, although by then they had been a major crop in Lancashire for decades. In the 1880s potatoes began to appear in recipes. In 1882 the "Household" column of The Manchester Times suggested:

Potatoes featured in a recipe printed in a Yorkshire paper in 1892 but, as in earlier versions, the main ingredients were beef and cabbage.

Modern versions
Possibly because of the scarcity of beef during food rationing in and after the Second World War, by the latter half of the 20th century the basic ingredients were widely considered to be cooked and mashed (or coarsely crushed) potato and chopped cooked cabbage. Those are the only two ingredients in Delia Smith's 1987 recipe. Clarissa Dickson Wright's 1996 version consists of crushed cooked potatoes, finely chopped raw onion, and cooked cabbage (or brussels sprouts), seasoned with salt and pepper, mixed together and shallow-fried until browned on the exterior. Like Smith, Dickson Wright specifies dripping (or lard) for frying, finding vegetable oil unsuitable for frying bubble and squeak, because the mixture will not brown adequately. Several other cooks find oil or butter satisfactory.

Fiona Beckett (2008), like Smith and Dickson Wright, stipulates no ingredients other than potato and cabbage, but there are many published variants of the basic recipe. Gary Rhodes favours sliced brussels sprouts, rather than cabbage, with gently cooked sliced onions and mashed potato, fried in butter. He comments that although the basic ingredients of bubble and squeak and colcannon are similar, the two are very different dishes, the former being traditionally made from left-overs and fried to give a brown crust, and the latter "a completely separate dish of potato, spring onion and cabbage, served almost as creamed potatoes".

Jeff Smith (1987) adds grated courgettes and chopped ham and bacon. Mark Hix (2005) adds cooked and chopped leeks and swede to the mix. Jamie Oliver (2007) adds chestnuts and "whatever veg you like – carrots, Brussels, swedes, turnips, onions, leeks or Savoy cabbage". Nigel Slater, in a 2013 recipe using Christmas leftovers, adds chopped goose, ham and pumpkin to the mixture.

The mixture is then shallow fried, either shaped into round cakes or as a single panful and then sliced. The first method is suggested by Delia Smith, Hix and Slater; Rhodes finds both methods satisfactory; Dickson Wright, Oliver and Jeff Smith favour the whole-pan method.

Outside Britain
Bubble and squeak is familiar in Australia; a 1969 recipe adds peas and pumpkin to the basic mix. The dish is not common in the US but is not unknown; an American recipe from 1913 resembles Rundell's version, with the addition of a border of mashed potato. In 1983 the American food writer Howard Hillman included bubble and squeak in his survey Great Peasant Dishes of the World. More recently Forbes magazine ran an article about the dish in 2004. A Canadian newspaper in 1959 reported a minor controversy about the origins of the dish, with readers variously claiming it as Australian, English, Irish and Scottish. In 1995, another Canadian paper called the dish "universally beloved".

Similar dishes

 * Panackelty, from north-east England
 * Rumbledethumps, stovies and clapshot from Scotland
 * Colcannon and champ, from Ireland
 * Stoemp from Belgium
 * Calentao, from Colombia
 * Biksemad, from Denmark
 * Bauernfrühstück and Stemmelkort, from Germany
 * Aloo tikki, from India
 * Stamppot, from the Netherlands
 * Trinxat, from the La Cerdanya region of Catalonia, northeast Spain and Andorra
 * Matevž, from Slovenia
 * Pyttipanna, Pyttipanne and Pyttipannu from Sweden, Norway and Finland
 * Hash, from the United States

Other uses of term
The OED gives a secondary definition of "bubble and squeak": "figurative and in figurative contexts. Something resembling or suggestive of bubble and squeak, especially in consisting of a variety of elements". In 1825 a reviewer in The Morning Post dismissed a new opera at Covent Garden as "a sort of bubble and squeak mixture of English and Italian". The OED gives examples from the 18th to the 21st centuries, including, from Coleridge, "... the restless Bubble and Squeak of his Vanity and Discontent", and from D. H. Lawrence, "I can make the most lovely bubble and squeak of a life for myself". In cockney rhyming slang the phrase was formerly used for "beak" (magistrate) and more recently "Bubble" has been used for "Greek".

The term has been borrowed by authors of children's books as names for a pair of puppies and (by two different authors) pairs of mice.

title: Bubble and squeak