What Do Brown Bears Eat? Salmon, Berries, Roots and More

A mostly plant-based omnivore

Despite their size and big teeth, brown bears are not specialist hunters. Their digestive system is short, like a carnivore’s, so they cannot digest tough plant fiber as well as a deer or cow. They make up for this by choosing the most nutritious plants at each time of year: young green shoots in spring, protein-rich flowers and leaves in early summer, sugary berries in late summer and fatty nuts in autumn.

The long, gently curved front claws and the muscular shoulder hump make brown bears outstanding diggers. They pull up roots, bulbs and tubers such as biscuitroot, glacier lily bulbs and sweet vetch, and they dig out ground squirrels and marmots.

How the diet changes through the year

Carrion is especially important in early spring, when bears leave their dens hungry and the snow reveals elk, bison or reindeer that died during the winter.

Salmon: the feast of coastal bears

In coastal Alaska, British Columbia and Kamchatka, spawning salmon swim up rivers each summer in huge numbers. Bears gather at waterfalls and shallow riffles to catch them, and at famous sites such as Brooks Falls in Katmai National Park dozens of bears can fish the same stretch of river. Older, larger males take the best spots, while young bears and mothers with cubs fish elsewhere.

Salmon are rich in fat and protein, and they are the main reason coastal brown bears are about twice as heavy as many inland grizzlies. When fish are plentiful, bears may eat only the most energy-rich parts, such as the skin, brain and eggs. The leftover carcasses, often dragged into the forest, feed scavengers and fertilize streamside trees with nutrients from the sea.

Moths, pine nuts and trout in Yellowstone

Grizzlies of the Greater Yellowstone area have few salmon, so they rely on other rich foods. In summer some bears climb to high rocky slopes to eat army cutworm moths that shelter under the rocks. A bear can eat tens of thousands of moths in a day, and for some bears these insects supply a large share of their yearly energy.

In autumn Yellowstone grizzlies seek the fatty seeds of whitebark pine, often by raiding the cone caches of red squirrels. Whitebark pine has declined sharply because of beetles, disease and a warming climate, and bears have shifted toward other foods, including more meat. In the past, grizzlies also caught spawning cutthroat trout in streams around Yellowstone Lake, but trout numbers fell after invasive lake trout spread in the lake.

Do brown bears hunt?

Yes, but how much depends on the bear. Many bears catch mainly small prey such as ground squirrels, marmots, voles and lemmings. In early summer, some become skilled at finding newborn elk, moose, caribou and deer calves hidden in the grass, and in Yellowstone grizzlies are an important predator of elk calves.

Adult moose, elk, caribou, muskoxen and bison are taken occasionally, most often when they are weak or stuck in deep snow. Brown bears also take over kills made by wolves and cougars; in Yellowstone, bears regularly push gray wolves off elk carcasses. Where people keep livestock in bear country, bears sometimes kill sheep or cattle, and they readily eat crops, orchard fruit, beehives and garbage.

What brown bears eat in Europe

European brown bears are even more plant-based than most North American bears. Studies in Scandinavia, the Carpathians and the Balkans show diets dominated by grasses and herbs in spring, ants and other insects in early summer, bilberries and other berries in late summer, and beech nuts, acorns, hazelnuts and fruit in autumn. Meat usually makes up only a modest share of the diet, mainly carrion, moose or reindeer calves and occasional livestock.

Fattening up for winter

From late summer, brown bears enter hyperphagia, a period of almost constant eating. They may feed for up to 20 hours a day and can gain more than 1 kg (2 lb) a day. A large bear may put on up to about 180 kg (400 lb) between spring and autumn. This fat must last the whole winter denning period, when most bears eat and drink nothing at all. Find out how much these bears weigh in how big do grizzly bears get?

Myths about what bears eat

• Myth: bears mainly eat honey. Fact: bees and their larvae are a minor food for most brown bears; plants, insects such as ants and moths, and fish matter much more.
• Myth: grizzlies are pure carnivores. Fact: the brown bear belongs to the order Carnivora, but it is a true omnivore.
• Myth: bears eat all winter. Fact: denning bears fast for months, living on their fat reserves.