The Evolution of the Polar Bear

How long have polar bears existed?

The most recent estimate of when polar bears diverged from brown bears is less than 500,000 years ago, although scientists continue to research this question.

After beginning to branch off, the polar bear's ancestors went through a series of evolutionary changes in order to survive in the Arctic.

How have polar bears adapted to the Arctic?

As time went on and the bears fanned out across the North, they became superbly adapted to a life of hunting seals and surviving extreme cold.

From top to bottom, their bodies are perfectly coordinated with the seasonal shifts in the Arctic. Their fur covers a thick layer of fat, their ears and tails are small to limit heat loss, and their paws allow them to tread on thin ice.

Learn more about polar bear characteristics here.

One of the most remarkable adaptations is their ability to thrive on a fat-rich diet without heart damage.

What Are We Learning?

• Polar bears have adapted to different types of sea ice habitats. Polar bears in the most northern regions of the Arctic show signs of genetic adaptations that allow them to survive on year-round ice cover.

• Polar bears are becoming smaller due to climate change. Smaller bears are more vulnerable than bigger bears, they typically can’t fast as long, and they have smaller cubs with lower survival rates.

• Polar bears are not evolutionarily adapting to climate change. While some individual bears show behavioural adaptions, like adopting new hunting strategies – we don’t see these adaptive changes in population-level genetic or evolutionary data.

• Polar bear - grizzly hybrids are rare. After brown bears and polar bears separated, there were periods when they came into contact again, particularly with polar bear genes flowing into grizzlies.

What’s in a Name?

Indigenous people in the North have had their own names for polar bears in many languages and dialects for thousands of years.

Later, the bears acquired names from scientists and explorers, including “polar bear” and their Latin name: Ursus maritimus, or “sea bear.”

Scientific Classification

Commander C.J. Phipps, author of “A Voyage Towards the North Pole”, used Ursus maritimus ("sea bear") for the first time in 1774. It refers to the animal's close association with the Arctic's chilly waters and sea ice.

Later, the scientific name, Thalarctos was accepted. It is a combination of the Greek, thalasso, meaning sea, and arctos, meaning bear of the North.

In 1971, polar bear scientists returned to the bear's original scientific name, Ursus maritimus.