Brown bearInteresting facts and information

• Giants of Alaska - Kodiak bears (Ursus arctos middendorffi), which live on Alaska's Kodiak Islands, are the largest brown bears: big males can weigh more than 600 kg and stand about 3 m tall on their hind legs.
• An amazing nose - Brown bears have a far better sense of smell than people and can detect food from kilometres away.
• Winter dormancy - In winter, brown bears rest in dens for months without eating or drinking; their heart rate slows, but they can wake up if disturbed.
• Standing up to look - Bears often stand on their hind legs to see and smell better; it is usually a sign of curiosity, not aggression.
• Fast runners - Over short distances, brown bears can reach about 50-56 km/h.
• Salmon makes them big - The largest brown bears live in Alaska and Kamchatka, where they feast on salmon.
• Excellent memory - Bears remember where and when they found food, even years later.
• Mostly plants - In many areas, plants such as berries, roots, grass and nuts make up most of a brown bear's diet.

• The brown bear (Ursus arctos) is a large mammal found in parts of North America, Europe and Asia. Its diet includes both plants and animals. Body size, seasonal activity and food vary greatly between populations.
• The most widespread bear - The brown bear has the largest range of any bear, from western Europe to Alaska.
• One of the largest land carnivores - Kodiak bears rival polar bears as the largest land carnivores.
• Close relatives - Brown bears and polar bears are so closely related that they can produce hybrids, sometimes called "pizzly" or "grolar" bears.

The brown bear is a large, powerful mammal with a hump of muscle on its shoulders, strong legs and adaptations that let it live in many different environments.

Essential physical adaptations

• Thick fur - A dense underfur and long guard hairs protect it against cold and rain.
• Long, strong claws - Front claws up to about 10 cm long are used for digging roots, dens and burrowing animals.
• A shoulder hump - This mass of muscle gives the front legs great power for digging.
• A large head with strong jaws - Can crush bones and chew tough plants.
• A very sensitive nose - Smell is its most important sense, used to find food and detect danger.
• Fat for the winter - In autumn, brown bears eat huge amounts and build up a thick layer of fat to survive the winter.
• Large feet - Like people, bears walk on the soles of their feet, which gives them stability on rough ground.

Brown bears mostly live alone, but they have a complex social life, especially where food is plentiful.

Way of life

• Bears are often most active in the early morning and evening, but where people are around they may become more nocturnal.
• They spend the winter in dens, but in mild climates some bears stay active for most of the year.
• Brown bears have large home ranges that often overlap; males may roam over hundreds or even thousands of square kilometres.
• They mark trees by rubbing and scratching them, leaving their scent.

Social interactions

• Although they usually live alone, many bears gather at rich food sources, such as salmon rivers, and form a temporary hierarchy.
• Mothers are very protective of their cubs and can be dangerous if they feel threatened.
• Bears recognise one another and avoid or challenge others depending on their size and status.

Defence and survival techniques

• Standing up - They stand on their hind legs to get a better view or smell, not necessarily as a threat.
• Avoiding fights - Bears usually avoid serious fights, but males can fight fiercely over females or food.
• Dens - They dig dens on slopes, under tree roots or in caves, where they spend the winter.

The brown bear is the most widespread bear in the world, living on three continents. There are about 200,000 brown bears in the world.

Species distribution

Habitats

• Forests - Boreal and temperate forests in Europe, Canada and Russia.
• Mountains - The Carpathians, the Alps, the Rocky Mountains and the Himalayas.
• Tundra - The open tundra of Alaska, northern Canada and Siberia.
• Dry regions - The Gobi Desert in Mongolia, where the rare Gobi bear lives.

Impact of climate change and human activities

• Habitat loss - Logging, roads and settlements reduce and break up bear habitat.
• Changes in the seasons - In some areas, warmer winters make bears leave their dens earlier, before much food is available.
• More contact with people - Bears looking for food come into villages, farms and towns more often.

The brown bear is an opportunistic omnivore that eats many different foods depending on the season and region. In some areas it eats mainly plants, while in others meat and fish are very important.

What does the brown bear eat?

Feeding methods

• Catching salmon - Brown bears in Alaska and Kamchatka catch salmon in rivers, sometimes snatching them in mid-air as they leap up waterfalls.
• Digging - They use their long claws to dig up roots, bulbs and burrowing animals.
• Hunting and scavenging - They catch young deer and other animals, eat carrion and sometimes take kills from wolves.
• Hiding food - They cover large carcasses with soil and leaves and return to them later.

Brown bears have an unusual breeding cycle called delayed implantation: the embryo only starts to develop if the mother has stored enough fat before winter.

Breeding season

• Mating takes place from about May to July, and males may travel long distances to find females.
• Males sometimes fight fiercely over females.
• After mating, the embryo does not develop straight away; it implants in late autumn only if the female is in good condition.

Pregnancy and birth

Raising cubs

• The cubs are born in midwinter in the den, while their mother is in her winter sleep.
• They stay with their mother for about 2-3 years, learning how to find food and avoid danger.
• The mother protects them fiercely, especially from adult males, which sometimes kill cubs.
• After leaving their mother, young bears look for their own home range.

Survival rate

• Many cubs die in their first years, killed by other bears, starvation or accidents.
• Bears that reach adulthood can live about 20-30 years in the wild.

Origin of name

• The English word "bear" comes from Old English bera, probably meaning "the brown one"; it may have been a nickname used to avoid saying the animal's real name.
• In Norse tradition, berserkers were warriors said to fight in bear skins with the fury of a bear.

Taxonomic Classification

Important subspecies and populations

Evolution and fossils

• Brown bears evolved in Eurasia from earlier bears of the genus Ursus.
• The oldest brown bear fossils are about half a million years old or more, and the species soon spread across Europe and Asia.
• Brown bears crossed into North America over the Bering land bridge during the last ice age.