What are the differences between polar, grizzly and black bears?

How do you know which bear you're seeing on a hike, hearing from inside your tent or which kind left tracks in the woods?

In the U.S., we live alongside three different bear species. We all know that, in spite of their cuddly appearance, humans should keep clear of bears for our safety and the bears. Still, if you happen to spot a bear from a safe distance, you might want to know more about which kind of bear you are looking at.

Black bear with cubs on road
Wikimedia Commons | CC-BY-SA-3.0
Black bear with cubs

How to know which kind of bear you’re looking at

The best way to distinguish between black and grizzly bears is their size and shape since both vary in color.

Black bears are the smallest of the three at two to three feet tall on all fours and up to six feet tall standing. Not all black bears are actually black in color – some are brown or “cinnamon” colored. And while they are the smallest North American bears, when fully grown they still outweigh most humans, with the males weighing 125 to 500 pounds and females weighing 90 to 300 pounds. They also have curved claws that help them climb.

USFWS | Public Domain

Grizzly bears are larger, heavier and shaped differently from black bears, with a distinctive shoulder hump. They also vary in color – some are black, some are brown and some are blond. They are usually between three feet and four feet tall on all fours but can be as tall as eight feet tall standing. Males weigh 400 to 600 pounds and females weigh 250 to 350 pounds, making them much more massive than black bears–and humans. Their paws also distinguish themselves from black bears, as grizzly claws are more suitable for digging than climbing.

Shutterstock | Shutterstock.com

If you’re not in Alaska and not at a zoo, the bear you just saw is a black bear or a grizzly bear.

Found only in Alaska, polar bears are the largest type of North American bear, and are the most distinctive in appearance. While everyone thinks of polar bears as having white coats,  their hairs are actually transparent and reflect back all of the colors. Still, if you are looking at them, they will mostly appear white. They are also massive: They can be taller than five feet on all fours and taller than eight feet standing. Males weigh 600 to 1200 pounds and females weigh 400 to 700 pounds. Polar bear paws are enormous, nearly a foot wide which helps spread their weight so they don’t fall through the ice. They also serve as paddles while the bears swim. Their pads are covered with bumps (“papillae”) which serve the same purpose as treads on our boots. They keep the polar bears from slipping.

What do bears eat?

All bears are omnivores, so they eat both plants and animals. Plants are easier to find in large quantities, such as huge fields of berries, so two types of bears get most of their food from plants.

Black bears mostly eat plants  – berries, fruit, grassy plants – and insects. Because they are adept at tree climbing, they can climb to find food. With an excellent sense of smell, they can find food from miles away, making them excellent scavengers. Because they eat seeds and berries, they also disperse them, providing a service to their ecosystem.

The grizzly bear diet is also mostly plants but they do eat more meat than black bears – including fish (particularly salmon when it’s available), small mammals and sometimes larger mammals. They scavenge carcasses and also kill smaller animals and young deer and elk. 

A brown bear captures a salmon in its jaws.
Peter Pearsall/USFWS | Public Domain

Polar bears eat the most meat, as they have fewer plants available to them due to their icy environs. Seals are a big part of their diet and they will also eat whale carcasses, when they can find them. When they can’t find seals or stranded whales, polar bears will hunt small rodents and fish and like their counterparts, they also eat berries.

Are bears endangered?

Black bears are not endangered and may be encountered in 40 out of 50 states in the U.S. Historically, they have lived in most of the forested regions of North America. As humans have built more roads and towns, their habitat has become more fragmented making it difficult to survive, so their range is smaller than it used to be.

Grizzly bears have a much more limited range, only living in Alaska, Idaho, Montana, Washington and Wyoming. They used to live across the western half of the country. People killed almost all of them starting in the 1800s through trapping, shooting and poisoning. By the time grizzlies were placed on the endangered species list in the 20th century, there were fewer than 1,000 grizzlies in the lower 48 states. They are now threatened by habitat loss, with smaller areas to roam, and food loss due to development and climate change. Grizzlies are also in danger from vehicles; famous grizzly bear mother #399 was killed by a vehicle in October 2024.

Polar bears in the United States are only found in Alaska because they only live in arctic ecosystems. They are extremely endangered, with population numbers in the hundreds. Polar bears were also hunted from the 1800s to the middle of the 20th century. Now, like the grizzly bears, they are losing their food sources and habitat due to climate change and warming temperatures in the arctic.

Beingmyself via Flickr | CC-BY-2.0

More fun trivia about bears

  • Black bear mating season occurs during the summer, but the embryos do not begin to develop until the mother bear enters her den. Cubs are born in the middle of the winter denning period, usually between mid-January and early February.
  • Female brown bears do not mate until they are at least four or six years of age. Mating season occurs from mid-May to mid-July and bears will mate with multiple partners during the season.
  • Only pregnant polar bears make winter dens on the sea ice.
  • Grizzlies and Polar bears can mate, offspring are called “grolar bears” and they are very rare.
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Authors

Ellen Montgomery

Director, Public Lands Campaign, Environment America Research & Policy Center

Ellen runs campaigns to protect America's beautiful places, from local beachfronts to remote mountain peaks. She sits on the Steering Committee of the Arctic Defense Campaign and co-coordinates the Climate Forests Campaign. Ellen previously worked as the organizing director for Environment America’s Climate Defenders campaign and managed grassroots campaign offices across the country. Ellen lives in Denver, where she likes to hike in Colorado's mountains.