Polar bears and grizzlies are two of the largest bear species in the world. They technically live in different geographic ranges and habitats; however, both species occur in Alaska and parts of Canada.
When stumbling upon one another, these two mammals could compete for resources. But who would win a fight?
Polar bears are larger than grizzly bears and over two times heavier. They have shorter canine teeth but more powerful jaws that can exert over 1,000 PSI of bite force. Polar bears also have larger paws and strike forces. They are almost exclusively carnivores, whereas grizzlies have an omnivorous diet. Surprisingly, though, grizzly bears are more likely to win the fight.
The table below shows a quick list of facts and comparison between grizzly bears vs. polar bears*:
|Throughout the Arctic
|Western North America
|Pack ice of the Arctic Ocean
|Woodlands, forests, prairies, alpine meadows
|6 to 10 feet long
|5 to 8 feet long
|330 to 1,700 pounds
|200 to 720 pounds
|35 miles per hour
|35 miles per hour
|11,500 to 59,500 lb.-ft./s
|7,000 to 25,200 lb.-ft./s
|Approx. 12 x 12 inches
|Approx. 5 x 7 inches
*Data in the table above was sourced from research papers, scientific journals, and other official sources.
Strike forces were calculated based on the top speed of 35 miles per hour and multiplied by the lightest and heaviest weight mentioned in the table for each species.
Polar Bear Vs. Grizzly Bear: 13 Key Differences And Similarities
Polar and grizzly bears alike are members of the Ursidae family and Ursus genus. However, they are different species.
Polar bears, called Ursus maritimus on their scientific name, are classified as ice-associated marine mammals. They roam large expanses of ice in the Arctic and are excellent swimmers, pursuing prey both on land and in the water.
Grizzly bears are a subspecies of brown bears or Ursus arctos. Their scientific name is Ursus arctos horribilis, and they are known for being one of the most lethal creatures seen in the wild.
Even though grizzly bears can swim and sometimes feed near bodies of water, they rarely swim to pursue prey.
2. Geographic Range
Both grizzly and polar bears live in the Northern Hemisphere, and they can sometimes occur in the same geographic range.
As their name suggests, polar bears live in the arctic regions. They are mostly found north of the Arctic Circle to the North Pole, occurring in Greenland, Alaska, Canada, Russia, and islands belonging to Norway.
Historically, grizzly bears were found in all of North America, from Alaska to Mexico. Today, however, they only occur in western North America, including western Canada, Alaska, Washington, Idaho, and Montana.
Polar bears are considered dependent on ice. Even though they prefer hunting on land, their historical natural habitat is limited to the pack ice of the Arctic Ocean.
Grizzly bears inhabit various territories, ranging from forests and woodlands to alpine meadows and prairies. Some of these territories are near the arctic regions.
Considering habitat preferences, polar and grizzly bears shouldn’t live in the same place. However, habitat reduction due to climate change has determined polar bears to move towards the inland.
Even though territory sharing between these two species is seldom, polar and grizzly bears have been observed together in the wild.
4. Body Size
The largest land carnivores in the world, polar bears are behemoths that grow to over 10 feet in length – some of the largest individuals even reached a record length of 12 feet.
They are not short either, with heights ranging from 3.5 to 5 feet at the shoulder.
Grizzly bears are large creatures, too, but they are smaller than polar bears. The two species are similar in height (when standing on all fours), but grizzlies only grow up to 8 feet long.
Polar bears are not only bigger than grizzlies, but they are also a lot heavier.
Specifically, polar bear males can weigh between 550 and 1,700 pounds. Females are visibly smaller than males, typically weighing between 330 and 650 pounds.
Grizzlies, even the largest ones, have about the same weight as polar bear females – between 200 and 700 pounds. Some large grizzly males may be heavier, but they rarely exceed 750 pounds.
6. Teeth Size
Despite their smaller bodies, grizzly bears have longer canine teeth than polar bears.
Grizzly cubs grow sharp canines about 0.5 inches in length by the time they are five months old. By adulthood, the fangs grow even longer, reaching lengths up to 3 inches.
Polar bears also have long and sharp canines, but their teeth are only about 2 inches in length. This gives grizzly bears an advantage.
7. Bite Force
Grizzlies may have longer fangs, but that’s about it. When it comes to actual bite force, polar bears get the upper hand once again.
According to a study, polar bears have the strongest bite of all bears.
In fact, they have strong jaws and can bite with force up to 1,235 PSI. Grizzly bears have strong jaws too, but their bite force is only about 975 PSI.
The higher bite force of polar bears is likely explained by the fact that they are the only bears in the world that have an almost exclusively carnivorous diet.
Polar and grizzly bears have similar speeds, although grizzlies can sometimes be faster.
Typically, polar bears run at speeds up to 25 miles per hour, although they can sprint up to 30-35 miles per hour in short bursts. They are also excellent swimmers, navigating through frigid waters at a speed of six miles per hour.
Grizzly bears can also reach speeds of 35 miles per hour for short periods of time; however, they can maintain a speed of about 28 miles per hour for long distances, which is faster than polar bears.
9. Strike Force
While there are no specific studies about the strike force of polar and grizzly bears, we can calculate the impact force of a bear.
The momentum is the result of mass multiplied by speed, and for the purpose of this writing, we considered the heaviest weight of each species and the top speed of 35 mph.
According to these calculations, polar bears can produce a strike force of up to 59,500 lb.-ft./s. This makes them over two times more powerful than grizzly bears, which can reach a max strike force of 25,200 lb.-ft./s.
10. Paw Size
A striking difference between polar bears and grizzlies is the paw size.
While polar bears are larger than grizzlies, they aren’t excessively larger. However, their paws are about two times the paw size of grizzly bears.
This difference is likely the result of polar bears’ adaptation to the environment – the larger paws make it easier to swim and walk on deep snow.
Both polar and grizzly bears are solitary mammals; the only exceptions are females caring for their dependent cubs and during mating season.
The main difference in behavior is that grizzly bears are often territorial, whereas polar bears are nomadic.
Grizzlies have home ranges that vary in size from 28 to 160 square miles, although some can be over 1,000 square miles in size.
Polar bears live in harsher climates where territory is less important than food availability.
These mammals travel wide ranges in search of food, and two or more polar bears can find themselves in the same territory at the same time.
When competing for resources, smaller individuals typically back out and leave the prey (or carcass) to the larger bear. The only exceptions are females with cubs, which often charge large males to protect their young.
While polar and grizzly bears are both omnivores, polar bears are often considered carnivores due to their almost exclusively carnivorous diet.
These mammals live in arctic areas that are covered in ice for most months. Vegetation in these territories is scarce, so seals and other marine mammals are the main food source.
However, in ice-free periods, polar bears also eat marine algae, lyme grass, berries, and even moss and mushrooms.
Grizzly bears are opportunistic omnivores and eat anything nutritious. Their diets consist of a variety of plant and animal materials, depending on season availability.
In instances when grizzly and polar bears find themselves in the same territory, the two could compete for resources.
13. Conservation Status
Grizzly bears are a subspecies of brown bears, and they are not threatened. The population is stable, and the species as a whole is considered the least concerned.
Due to climate change, polar bears are constantly losing their habitat. They are not yet considered threatened, but scientists estimate that polar bears could become extinct by 2100.
Who Would Win A Fight?
From larger bodies to more powerful bites, polar bears seem to have the upper hand. They are technically stronger than grizzlies and also hunt more frequently.
Nevertheless, grizzlies are more likely to win the fight – if it ever comes to a fight, that is.
In research on grizzly and polar bear interactions in Alaska, scientists discovered that 71% of encounters between these two species are non-aggressive and result in the submissive response of the polar bears present at the feeding site.
It was also observed that grizzlies initiated all aggressive interactions, the only exceptions being polar bear females with cubs that charged grizzly males to defend their young. However, females with cubs typically avoid feeding sites when grizzlies are present.
According to this study, polar bears are subordinate to grizzlies, withdrawing from the feeding site before it comes to a fight.