grizzly bears quick facts
- The grizzly is a kind of brown bear.
- Grizzlies eat more than 260 kinds of food.
- They hibernate for four to six months each year.
- Grizzlies can run at up to 56 to 64 km/h in short bursts.
- About 1,900 grizzlies live in the lower 48 US states.
What is a grizzly bear?
The grizzly bear is a large North American brown bear. Britannica explains that it is a subspecies of the brown bear, with the scientific name Ursus arctos horribilis.
Grizzlies are famous for their size, strength and the big hump on their shoulders. They live in the forests, mountains and open country of western North America.
Male grizzlies usually live alone and roam huge areas. The home range of a male can stretch across hundreds or even thousands of square kilometres.
| Grizzly bear at a glance | |
|---|---|
| Scientific name | Ursus arctos horribilis |
| Weight (lower 48 states) | males 180 to 270 kg; females 110 to 160 kg |
| Top speed | about 56 to 64 km/h (35 to 40 mph) in short bursts |
| Food | more than 260 kinds, from berries and roots to fish and elk calves |
| Winter | hibernates in a den for 4 to 6 months |
| Cubs | usually two, born in January or February |
| Lifespan | 20 to 30 years |
Why is it called a grizzly?
A grizzly’s fur is usually brownish, but the tips of the hairs are silver or pale. Britannica says this gives the fur a “grizzled”, or grey-flecked, look, which is where the bear gets its name.
The US Fish and Wildlife Service says grizzly fur ranges from light brown to nearly black, with silver or golden tips.
As a kind of brown bear, grizzlies are related to brown bears across Europe and Asia. The brown bear as a whole species is not endangered, but in the lower 48 states of the USA, grizzlies are protected because so few are left.
What does a grizzly bear look like?
Grizzlies have a big hump of muscle on their shoulders, which powers their front legs for digging. Britannica says they also have a raised forehead, which gives the face a dished, or concave, shape.
Their front claws are long and fairly straight. The National Park Service says a grizzly’s claws average about 4.5 cm (1.8 inches) and can be up to 15 cm (5.9 inches) long.
Because of their weight and long, straight claws, Britannica says grizzlies rarely climb trees.
Grizzly or black bear? The Fish and Wildlife Service says you can tell a grizzly by its longer, less curved front claws, its humped shoulders and its dished face. Colour is not a good clue, because black bears can be brown too.
How big is a grizzly bear?
The Fish and Wildlife Service says adult male grizzlies in the lower 48 states weigh about 180 to 270 kg (400 to 600 pounds), and females about 110 to 160 kg (250 to 350 pounds).
The National Park Service says the average adult male in the Yellowstone area weighs 187 kg (413 pounds). The heaviest known male there weighed 324 kg (715 pounds).
Britannica says large adult grizzlies can be about 2.5 m (8 feet) long and weigh about 410 kg (900 pounds).
Grizzlies can be surprisingly fast. Britannica says they can run at up to 56 km/h (35 mph) over short distances, and the National Park Service gives 56 to 64 km/h (35 to 40 mph). That is faster than any human.
Grizzly by Numbers
- 180 to 270 kg — An adult male's weight in the lower 48 states
- 110 to 160 kg — An adult female's weight in the lower 48 states
- 324 kg — The heaviest known male in the Yellowstone area
- 56 to 64 km/h — Its top speed in short bursts
- About 2.5 metres — The length of a large adult
Where do grizzly bears live?
Grizzlies once lived across much of western North America, from Alaska to Mexico and out onto the Great Plains. Britannica says the explorers Lewis and Clark reported them in eastern Montana in 1804.
The Fish and Wildlife Service says about 50,000 grizzlies once lived in 18 western states. By the 1930s, they were left in only about 2% of their former range.
Today, grizzlies are still common in Alaska and Canada. In the lower 48 states, they live in a few areas, such as the Greater Yellowstone region and north-western Montana.
Marking their territory
Grizzlies leave signs to tell other bears they are around. Britannica says that each spring a grizzly marks its territory by rubbing against trees, scratching the bark and even biting large pieces out of tree trunks.
These rubbing trees are like noticeboards. Other bears can smell who has passed by.
Grizzly senses
Britannica says a grizzly’s eyesight is poor. But its sense of smell is excellent, and it uses its nose to find food, from berries to carcasses, a very long way off.
Grizzlies often stand up on their back legs. They do this to get a better look and a better sniff of the air, not usually because they are about to attack.
What do grizzly bears eat?
Grizzlies are omnivores, which means they eat both plants and animals. The Fish and Wildlife Service says grizzlies in the Greater Yellowstone area eat more than 260 different kinds of food.
Britannica says they eat berries, roots, shoots, small mammals, fish, the young of hoofed animals such as elk, and carrion, the bodies of animals that have already died.
Grizzlies are powerful diggers. They dig up roots and bulbs, and they dig into burrows to catch ground squirrels and other rodents. They sometimes bury extra food in shallow holes to eat later.
In late summer and autumn, grizzlies eat almost constantly to build up fat for winter. The National Park Service says a grizzly normally needs 5,000 to 8,000 calories a day, but at this time of year it may eat up to 20,000.
What Grizzlies Eat
- Omnivore — An animal that eats both plants and animals
- Carrion — The bodies of animals that have already died
- Elk calves — Young hoofed animals a grizzly may catch
- Ground squirrels — Rodents a grizzly digs out of their burrows
- A shallow hole — Where a grizzly may bury extra food
- Up to 20,000 calories — What a grizzly may eat in a day in autumn
The long winter sleep
Grizzlies spend the winter in dens. The Fish and Wildlife Service says they hibernate for four to six months each year, usually going into their dens between October and December.
Before that, they gain weight fast, as much as 1.6 kg (3.6 pounds) a day. During hibernation they live off the fat stored in their bodies.
The National Park Service says females with cubs stay in their dens the longest, about 171 days on average, while males stay about 131 days.
Grizzly cubs
Grizzly cubs are born in the den in the middle of winter, in late January or early February. Britannica says the cubs are most often twins, and they weigh less than 1 kg at birth.
The National Park Service says a mother has one to four cubs, about two on average. The cubs stay with her for 18 months to three and a half years, about two and a half years on average.
Mother grizzlies protect their cubs fiercely. Britannica says females with cubs are the most aggressive grizzlies.
Grizzlies have one of the slowest breeding rates of any land mammal. The Fish and Wildlife Service says females first have cubs at about six years old and then wait about three years between litters.
A Grizzly’s Year in Order
- Spring It marks its territory by rubbing, scratching and biting tree trunks.
- Late summer It eats almost nonstop to build up fat for winter.
- October to December It goes into its den.
- January or February A mother's cubs are born in the den, weighing less than 1 kg.
- Spring again The bears come out of their dens.
How long do grizzly bears live?
The National Park Service says grizzlies live for about 20 to 30 years. The oldest known grizzly in the Yellowstone area was 31.
Grizzly neighbours
When a grizzly leaves part of a carcass, other animals move in. Ravens, foxes, eagles and other scavengers feed on the leftovers.
Grizzlies also share their range with wolves, and the two sometimes compete over carcasses. Their closest living relatives include the polar bear.
Grizzlies, Kodiak bears and black bears
Kodiak bears, which live on Kodiak Island and nearby islands in Alaska, are sometimes called grizzlies. Britannica says they are a different subspecies of brown bear and are bigger, and their range does not overlap with the grizzly’s.
Britannica says the largest Kodiak bears can weigh up to 720 kg (1,600 pounds), rivalling the polar bear as the world’s largest land carnivore.
American black bears are sometimes mistaken for grizzlies too, because in the west many black bears are brown.
Grizzlies in stories and symbols
Grizzly bears feature in many Native American stories, according to Britannica. They were respected as powerful animals.
The grizzly is also the state animal of California, and it appears on the state flag, even though no wild grizzlies have lived there for about a hundred years.
Why grizzlies disappeared
As settlers moved west in the 1800s and early 1900s, grizzlies were shot, trapped and poisoned, and their land was turned into farms and towns.
The Fish and Wildlife Service says the main threats today still come from people, including busy roads and trails into bear country, conflicts over livestock, and loss of habitat.
Grizzlies and people
Grizzlies usually avoid people, but they can be dangerous, especially if surprised or when a mother is protecting her cubs.
In national parks, visitors are told to make noise on trails, travel in groups, carry bear spray and never leave food where bears can reach it.
The Fish and Wildlife Service says grizzlies in the lower 48 states are protected as a threatened species, and it is illegal to harm, harass or kill them except in self-defence.
Numbers have been recovering. The Fish and Wildlife Service says about 1,900 grizzlies now live in the lower 48 states. Britannica gives an older figure of fewer than 1,500.
Could a grizzly beat a gorilla? Find out in our gorilla versus grizzly bear guide.
Three things people get wrong
Grizzlies are not a separate species. They are a kind of brown bear.
Grizzlies do not only eat meat. They eat more than 260 kinds of food, including many plants.
You cannot outrun a grizzly. They can run at up to 56 to 64 km/h in short bursts.
Did you know? A grizzly’s name comes from its silver-tipped hairs, which give its fur a grizzled, grey-flecked look.
Grizzly Bears: Fact or Myth?
- Grizzlies are a separate species from brown bears.
- A grizzly's eyesight is poor.
- Grizzlies eat only meat.
- Grizzlies rarely climb trees.
- A person can outrun a grizzly.
- The grizzly is the state animal of California.
- A grizzly standing on its back legs is usually about to attack.
- Kodiak bears are a different kind of brown bear from grizzlies, and bigger.
Try it
Measure 15 cm with a ruler. That is how long the biggest grizzly claws can be.
Knowledge check
How can you tell a grizzly from a black bear?
Show answer
By its shoulder hump, dished face and longer, straighter claws.
How long do grizzlies hibernate?
Show answer
Four to six months each year.
Frequently asked questions
How big is a grizzly bear?
Adult male grizzlies in the lower 48 states weigh about 180 to 270 kg, and females 110 to 160 kg. The largest can weigh over 400 kg.
What do grizzly bears eat?
Grizzlies are omnivores. They eat more than 260 kinds of food, including berries, roots, fish, rodents, elk calves and animals that have died.
How fast can a grizzly bear run?
Britannica says grizzlies can run at up to 56 km/h (35 mph) over short distances. The National Park Service gives 35 to 40 mph.
How long do grizzly bears hibernate?
Grizzlies hibernate in dens for four to six months each year. Mothers with cubs stay in the longest, about 171 days on average.
How many grizzly bears are left?
About 1,900 grizzlies live in the lower 48 US states, where they are protected as threatened. Many more live in Alaska and Canada.
What is the difference between a grizzly and a black bear?
Grizzlies have a shoulder hump, a dished face and longer, straighter front claws. Colour is not a reliable clue, because black bears can be brown.
Sources
- US Fish and Wildlife Service: grizzly bear — size, how to tell grizzlies from black bears, diet, hibernation, breeding rate, range, population, status and threats
- Encyclopaedia Britannica: grizzly bear — subspecies, name, appearance, size, speed, diet, dens, cubs, history and population
- US National Park Service: Yellowstone grizzly bear facts — weights, claw length, energy needs, denning, cubs, speed and lifespan in the Yellowstone area
Grizzly Bear Final Challenge
- Where does the grizzly get its name?
- About how many grizzlies once lived in the western United States?
- By the 1930s, how much of their old range were grizzlies left in?
- Where do most of the threats to grizzlies come from today?
- What are visitors to bear country told to carry?
- On average, how long do grizzly cubs stay with their mother?
- Why do grizzly numbers recover so slowly?
- Which grizzlies are the most aggressive?
