Bear

• 1. Introduction

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  Bears are so deeply woven into human language that the very word for them is a cover story. Proto-Germanic tribes refused to speak the animal's true name, arkto, out of fear that saying it aloud might summon the creature. So they invented a substitute: a word meaning roughly "the brown one", from which the Old English bera descended, and from which we get "bear" today. According to author Ralph Keyes, this is the oldest known euphemism in recorded language.

  This act of avoidance speaks to something elemental. Bears have been shaping human thought since at least the Paleolithic, and the constellation Ursa Major has been associated with a bear for as many as 13,000 years. Today, only eight species survive. They range from the Arctic ice to the tropical rainforests of Southeast Asia. The smallest, the sun bear, weighs as little as 25 kilograms. The largest, the polar bear, can tip the scales at 700 kilograms.

  What makes bears so persistent a presence in human imagination? And how did a small, raccoon-like creature from the Eocene give rise to one of the most successful and recognizable animal families on Earth? The answers move through deep evolutionary time, across every continent except Australia and Antarctica, and into the living rooms of children who sleep beside stuffed toys named for an American president.

• 2. An Ancient Lineage

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  Parictis, one of the earliest members of the bear family Ursidae, roamed North America somewhere between 38 and 18 million years ago. It looked nothing like a modern bear. Small and raccoon-like in overall appearance, it probably had a diet closer to a badger than to a grizzly. Yet from creatures like this, every living bear descends.

  The key transitional genus was Ursavus, which arose during the early Oligocene around 30 to 28 million years ago from a Cephalogale-like ancestor. Ursavus proliferated across Asia and is considered ancestral to all living bears. A single species, Ursavus elmensis, is the likely pivot point from which the modern lineages branched. Members of living bear lineages diverged from Ursavus between 15 and 20 million years ago.

  The pandas were the first to split off, around 19 million years ago, though no panda fossils have been found before about 11 million years ago. The ancestors of the spectacled bear arrived in South America following the formation of the Isthmus of Panama, approximately 2.5 or 1.2 million years ago. Their earliest North American fossil representative is Plionarctos, which dates to roughly 10 to 2 million years ago.

  The subfamily Ursinae, which contains six of the eight living species, underwent a rapid burst of diversification between 5.3 and 4.5 million years ago, coinciding with major environmental changes. The sloth bear diverged early in this radiation. By 3 to 4 million years ago, a species called Ursus minimus was present in European fossil beds; it was nearly identical to today's Asian black bear and is likely ancestral to all ursine bears. The polar bear is the youngest of all: it descended from a population of brown bears isolated in northern latitudes by glaciation around 400,000 years ago.

• 3. Bodies Built for Survival

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  Polar bears have hollow, translucent guard hairs that conduct heat from sunlight down to their dark-colored skin beneath. That single anatomical fact captures something important about how precisely each bear species has been shaped by its environment, while still sharing a common toolkit.

  All eight species are plantigrade, meaning they walk on the flat of the foot rather than on the toes. This distributes their weight toward the hind feet and produces what observers describe as a lumbering gait. It also allows bears to stand upright with remarkable balance. Their forelimbs are dense and powerful, used for digging, striking, climbing, and gripping. The claws are non-retractile and larger on the front feet than the rear; black bears, the most arboreal of the species, have the shortest front claws.

  The giant panda carries an unusual adaptation on its wrist: a bony extension that functions as a thumb. It grips bamboo shoots with this structure, which is not a true digit but serves the same purpose. The panda's diet is over 99% bamboo, drawn from 30 different species, and the animal spends 12 to 15 hours a day feeding to extract enough nutrition from such a low-calorie plant.

  Sloth bears lost several front teeth found in other bears and developed protrusible lips and a long suctioning tongue to vacuum up termites and ants. At certain times of year, insects make up 90% of a sloth bear's diet. Polar bears, by contrast, appear to have secondarily re-evolved carnassial-like cheek teeth as their diet shifted back toward meat. The general bear skull is massive, providing anchorage for powerful jaw muscles, with flat crushing molars and large canines used mainly for display.

  Bears have a sense of smell that exceeds that of a dog, and possibly any other mammal. They locate carcasses from several kilometres away. They also have color vision, unusual among carnivorans, which likely helps them distinguish ripe fruit. What they lack is sharp hearing or acute eyesight; their small rounded ears are built to minimize heat loss, not to pick up distant sounds.

• 4. How Bears Eat and Sleep

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  A brown bear can consume 41 kilograms of food in a single day and gain 2 to 3 kilograms of fat during that same period, all in preparation for entering its winter den. The sheer scale of that intake reflects the urgency of hibernation.

  During hibernation, the bear's heart rate drops from a normal 55 beats per minute to as few as 9. Its body temperature falls by 4 to 7 degrees Celsius. A protein called myosin, found in the heart muscle, enters a super-relaxed state that dramatically reduces the cell's consumption of ATP, allowing the animal to sustain basic functions without eating, drinking, urinating, or defecating for up to 100 days. When the bear wakes in spring, a fecal plug that formed in the colon is expelled.

  Researchers found a counterintuitive pattern: smaller bears can hibernate longer than larger ones, because they sustain a lower body temperature and therefore spend less energy on warmth. Female bears give birth during this dormant period and are briefly roused by the process. Cubs are born blind and nearly hairless, entirely dependent on their mother for heat.

  Outside of winter, most bears are opportunistic omnivores. Asiatic black bears in Taiwan shift their diet from acorns, when those are abundant, to ungulates at other times of year. Brown bears gather in large numbers at salmon runs, wading in and seizing fish with their jaws or paws, preferring to eat the brain and eggs. Spectacled bears eat bromeliads, which can make up 50% of their diet, and have strong enough jaws to bite the plants open. In autumn, some bear species consume large amounts of naturally fermented fruit, which affects their behavior. Sun bears use their long tongues to reach both honey and insects from the same source.

• 5. Cubs, Courts, and Conflicts

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  Mating in bears has been described by researchers as polygyny, promiscuity, and serial monogamy, depending on the species. A male may visit a female continuously for several days or weeks, testing her reproductive state. Some Asian bear species include wrestling, hugging, and mock fighting in their courtship. Ovulation is induced by mating, which can last up to 30 minutes.

  Gestation typically runs six to nine months, including a period of delayed implantation. Giant pandas may give birth to twins, but the mother can suckle only one, and the other is left to die. Male bears take no part in raising young. Infanticide by adult males has been recorded in polar bears, brown bears, and American black bears; males kill cubs to bring the female back into estrus.

  Mothers are fierce in defense of their young, even at the cost of their own lives. Cubs may suckle for up to a year and can follow their mother outside the den by two to three months. Sloth bear cubs sometimes ride on their mother's back. Young bears typically reach sexual maturity at around three to six years, though male Alaskan brown bears and polar bears may continue to grow until they are 11 years old.

  Bears communicate through a layered vocabulary of sound and posture. Tongue-clicking and chuffing signal calm; barking signals alarm; bellows and roars accompany aggressive encounters. Dominance is asserted through a frontal posture with canine teeth exposed and neck stretched. Subordinates respond by turning sideways, lowering the head, and sitting or lying down. Scent also carries messages: pandas mark territories with urine and a waxy secretion from their anal glands, while polar bears leave scent in their tracks across the ice, allowing individuals to track one another across vast distances.

• 6. Myth, Name, and Culture

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  At Brauron, in ancient Greece, young Athenian girls underwent an initiation rite in which they were called arktoi, meaning "she bears", as part of the archaic cult of Artemis. The constellation Ursa Major, associated with a bear since Paleolithic times, takes its name from the same root. The star Arcturus, nearby in the sky, means "guardian of the bear", as though standing watch over the two bear constellations that Ptolemy named.

  Artio, a Celtic bear goddess also known as Dea Artio in the Gallo-Roman tradition, was worshipped at Bern in present-day Switzerland. Bern itself is named for the bear, from the German Bär. Her name derives from artos, the Celtic word for bear. The male Swiss first name Urs and the female name Ursula both carry the same Latin root, ursa, meaning she-bear; Ursula specifically means "little she-bear".

  The Germanic name Bernard, including its variant Bernhardt, means "bear-brave" or "bold bear". The Old English name Beowulf is a kenning for bear, translating as "bee-wolf". The Swedish name Björn, also common as a given name, shares this same family of Germanic bear words.

  In many Native American cultures, the bear's hibernation and re-emergence made it a symbol of rebirth. Cultures across North America and northern Asia associated bears with shamans; the solitary nature of both was one apparent link. The prehistoric Finns, Siberian peoples, and, more recently, Koreans regarded the bear as the spirit of their forefathers.

  Children's literature is saturated with bears. Robert Southey published an early version of "The Three Bears" in 1837, later illustrated by Arthur Rackham in 1918. The Care Bears began as greeting cards in 1982 before expanding to toys and film. The teddy bear traces to 1902, when Theodore Roosevelt refused to shoot an American black bear that had been tied to a tree, and toy makers named the stuffed animal after him.

• 7. Pressure from Every Direction

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  More than 12,000 bears are thought to be held on farms in China, Vietnam, and South Korea, kept for the production of bile used in traditional Chinese medicine. Bear bile has been detected in shampoos, wine, and herbal medicines sold in Canada, the United States, and Australia, despite trade in bear products being prohibited under the Convention on International Trade in Endangered Species.

  The IUCN lists six bear species as vulnerable or endangered. Even the brown bear and the American black bear, both classified as least concern globally, face local extirpation in parts of their range. The Atlas bear, a subspecies of the brown bear once found from Morocco to Libya across North Africa, went extinct around the 1870s.

  Bears were kept for baiting in Europe from at least the 16th century. Five bear-baiting gardens operated in Southwark, London, during that period; archaeological remains of three have survived. Romani bear handlers called Ursari traveled across Europe from the 12th century onward, earning a living by busking with trained bears.

  The Sichuan Giant Panda Sanctuaries, which shelter around 30% of the world's wild panda population, received a UNESCO World Heritage Site designation in 2006. Specialty organizations now exist for each of the eight species, from Polar Bears International to the Bornean Sun Bear Conservation Centre to the Chengdu Research Base of Giant Panda Breeding. Smokey Bear, introduced in 1944 with the message "Only you can prevent forest fires", became an enduring fixture of American public life, carrying the idea that individual human behavior shapes the fate of wild places.