The Biggest Grizzly Bear to Ever Roam Yellowstone

Many incredible predators live in our National Parks, including mountain lions, wolves, and bears. But do you know just how big the biggest grizzly bear (Ursus arctos horribilis) to ever roam Yellowstone National Park was? How did the immense size of this bear compare to other grizzlies in the wild, and what did it need to eat to get so big? Keep reading to learn more about the biggest grizzly bear to ever live in Yellowstone.

How Big Was the Biggest Grizzly Bear to Ever Roam Yellowstone?

According to Yellowstone biologist and Interagency Grizzly Bear Study Team leader Frank van Manen, the largest grizzly to ever roam Yellowstone was encountered in 1977. This massive bear weighed a whopping 715 pounds. At 712 pounds, Grizzly 566 is the second-largest bear ever documented in the Yellowstone ecosystem. When he was caught in 2023, he was the heaviest grizzly bear assessed in the Greater Yellowstone area in 46 years.

Bear 791 has also been rumored to be the largest grizzly in Yellowstone. He was caught on film killing and eating an enormous male elk in 2020. The bear was estimated to be 9 years old and weigh between 600 and 700 pounds. However, 566 and 791 aren’t the only large grizzlies. Yellowstone National Park and the surrounding ecosystem have known plenty of large bears. In 2018, a grizzly known affectionately as Big Joe was unfortunately euthanized due to his routine hunting of cattle outside of Yellowstone. This bear was captured right after hibernation, likely at his lowest weight, and he still weighed over 600 pounds. Experts estimate that, if Big Joe had survived, he could have weighed nearly 900 pounds by the fall.

Another bear, nicknamed Little Wahb, was caught and euthanized for the same reason as Big Joe back in the year 2000. Also known as Bear 212, Little Wahb was estimated to weigh between 600 and 800 pounds. Now, Little Wahb and Big Joe remain in a museum near Yellowstone National Park, educating visitors about grizzlies year after year.

How Big is the Average Grizzly Bear?

The average male grizzly bear weighs 400 to 600 pounds. However, as shown above, some large males can weigh even more. Female grizzly bears typically weigh 250 to 350 pounds. Grizzly bears typically range from 5 to 8 feet long and can stand 3.5 to 4.5 feet at the shoulder.

As large as they are, grizzlies are not the biggest brown bears. Kodiak bears (Ursus arctos middendorffi), a specific subspecies of brown bears living in the Kodiak Archipelago off the coast of Alaska, are considered to be the largest brown bears ever. Kodiak males can weigh anywhere from 600 to 1,400 pounds, although some males may be even larger. Females weigh 300 to 700 pounds, which is around the same size as large male grizzlies.

What Do Grizzly Bears in Yellowstone National Park Eat?

There may be a number of carnivores and predators in Yellowstone, but grizzlies reign supreme. Grizzly bears in Yellowstone eat a number of different animals, including elk, deer, bison, moose, rabbits, fish, and rodents. In fact, grizzlies were documented to eat 266 different species from 200 genera and 4 kingdoms. That includes plants, mammals, fungi, fish, and even algae, among others.

Some of the most commonly eaten foods include ants, pine seeds, clover, elk, dandelion, and thistle. Before the refuse dumps were closed, garbage was also a large part of the grizzly diet. They devour enough food in the fall to gain three pounds per day, in preparation for their long winter hibernation.

Where Can I See Grizzly Bears in Yellowstone National Park?

While you may not want to see a grizzly bear during your time in Yellowstone National Park, it is one of the top places in the entire world to see carnivores in their natural habitat. This includes wolves, black bears, and, of course, grizzly bears. They have been sighted along the Northern Ridge of the park, in both Hayden and Lamar valleys, and more.

However, grizzly bears tend to avoid humans and are more elusive than black bears and non-carnivorous animals. You are much more likely to see bison and elk before spotting a grizzly. Nevertheless, grizzlies are still prominent within the park. You should plan accordingly and take safety precautions in bear country, especially if you want to camp anywhere in Yellowstone National Park. Remember: grizzly bears are often aware of your presence long before you are aware of theirs.