Scientists have recorded grizzly bears in the Greater Yellowstone area eating more than 260 kinds of food. Grizzly bears eat both plants and animals.
From March through May, elk and bison make up a large part of a grizzly bear's diet in Yellowstone. In spring, grizzlies also eat new green grasses and other young plants.
Around Yellowstone Lake, grizzly bears feed on cutthroat trout that come up streams to spawn.
Around midsummer, Yellowstone grizzlies start eating strawberries, huckleberries, whortleberries and buffaloberries.
Army cutworm moths fly long distances in early summer from farm fields on the Great Plains up to alpine slopes in the mountains. In summer, some grizzlies climb to high mountain slopes where moths gather, and eat them.
In September and October, whitebark pine nuts are the most important food for Yellowstone grizzlies in years when the seeds are plentiful.
A grizzly bear is one kind of brown bear. Brown bears on the coast depend on the yearly runs of salmon swimming up rivers. Where fish are plentiful, a brown bear can eat up to 90 fish in a single day. Once salmon-eating brown bears are less hungry, they eat only the eggs, brains and skin of the salmon, the most nutritious and fatty parts.
A brown bear can follow the scent of a rotting carcass for more than two miles. A grizzly's hearing is about like ours, and its sense of smell is the one it depends on most.
Hyperphagia is the time in fall when a grizzly eats far more than usual and turns the extra food into fat. The fat a bear stores for winter gives it energy and also keeps it warm. A bear in its den lives on that fat. All winter in the den, it does not eat or drink.
In the lower 48 states, adult female grizzly home ranges vary from 50 to 150 square miles, and an adult male's can be up to 600 square miles. Grizzly bears have home ranges that overlap with other bears' ranges. They do not guard a territory.
Words to know
- spawn: lay eggs
- carcass: dead animal body
- alpine: high mountain
- hyperphagia: eating a lot
- territory: guarded land
