Polar Bear vs. Grizzly Bear: Which Bear Is Bigger and Tougher?

Polar bears (Ursus maritimus) are the largest bear species, with a male polar bear weighing up to 1,500 pounds. Their bodies are built for cold environments, with a thick layer of fat and dense fur to keep them insulated. Female polar bears are smaller but still powerful predators.

Grizzly bears (Ursus arctos), also known as North American brown bears, vary in size depending on their location. Kodiak bears, a type of brown bear, can rival polar bears in weight, while barren ground grizzlies tend to be smaller. Male grizzly bears are formidable and can take on nearly any predator in their territory.

Both of these bears are apex predators in their environments without natural predators. These two species both boast a bite force of over 1,000 pounds per square inch, which is enough to crush any unlucky creature that might end up in their jaws.

Polar bear habitats consist of the far-north Arctic, where they rely on sea ice for hunting and travel. Populations are concentrated in northern Canada, northern Alaska, Greenland, Russia and Ukraine.

These bears are excellent swimmers and can cover long distances in search of food. Female polar bears often build dens in snowdrifts to protect their cubs from the harsh cold while raising cubs in the Arctic environment.

Grizzly bears thrive in a much more varied landscape, from forests to grasslands. Unlike polar bears, they are not reliant on ice and are more adaptable to changing climates.

While grizzlies prefer to stay on land, they are strong swimmers and occasionally hunt fish in rivers and streams. Grizzly bears also have longer claws to help them dig up grubs or forage for food along the forest floor.

Grizzly bear populations can be found in the western United States and Canada although U.S. populations have dwindled since the 20th century.

When it comes to food, polar bears are specialized hunters with a preference for hunting seals. They rely on sea ice as a platform for ambushing their prey, using their powerful sense of smell to detect seals beneath the ice. Without sea ice, their ability to find food becomes much more difficult.

Grizzly bears have a more varied diet, eating everything from berries to small mammals like ground squirrels, and even scavenging carcasses.

While female grizzlies and their cubs may forage for plants, male grizzlies are known for taking down large prey like moose. Their ability to adapt their diet makes them more resilient in changing environments.

With climate change affecting the polar bear's environment, encounters between polar bears and grizzlies are becoming more common, resulting in hybrid bears — specifically grolar bears and pizzly bears — have been discovered.

These bears inherit traits from both parents, blending the hunting skills of polar bears with the adaptability of grizzlies.

Hybrid grolar bears are sometimes bred in captivity but are a much rarer sight in the wild. A 2024 analysis of about 800 polar bears and grizzly bears across North America and Greenland found that only eight of the sample displayed hybrid genes.

This DNA evidence suggests that about 1 percent of the two species are currently hybridized.

While hybrid bears are rare, they highlight the challenges these species face in a changing world. Whether raising cubs on the Arctic ice or roaming forests in search of food, both species have evolved to be top predators in their environments.

We created this article in conjunction with AI technology, then made sure it was fact-checked and edited by a HowStuffWorks editor.