Grizzly Bears

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Order: Carnivora
Family: Ursidae
Genus: Ursus
Life Span: 20 - 25 years
Population: 60,000
Species Status: Threatened

Fun Factoid

Fun Factoid: Did you know? Even though Grizzlies share similar territory with Polar Bears, Grizzlies live exclusively on land, while Polar Bears live mostly on sea ice.

Welcome to the world of Grizzly Bears (Ursus arctoc horribilis)! Grizzly Bears, also known as Grizzlies, are a subspecies of Brown Bear that live exclusively within the North West region of North America. In total, there are eight different subspecies of Brown Bears found throughout the world in the forests of North America, Europe, and even Asia. The closest relative of the Grizzly is actually the Polar Bear, due to their similar anatomy and genetics. They are so closely related it is even possible for them to breed and have cubs, however, due to their difference in habitat, they rarely ever do so. Grizzly Bears are massive, and although they are smaller in size than Polar Bears, they weigh anywhere from 290 – 600 lbs, and on their hind legs they can stand almost 9 ft tall!

Geography

Fun Factoid

Did you know? Grizzly Bear populations are slowly rising in places like Yellowstone National Park!

Grizzly Bears used to have a range that spanned the entire West half of the North American continent. From modern day Alaska, all the way down to half way through modern day Mexico, and across to the great lakes. However, today their current territory is restricted to the most North West section of North America. This range is almost entirely within Alaska, and West Canada, with only a few hundred bears left within the U.S. states of Wyoming, Montana, Idaho, Washington, and Colorado. The largest population of Grizzly Bears is found in Alaska, where about 30,000 individual bears live. Grizzly Bears, like Black Bears, can be found in prairies, forests, meadows, and they are always found around rivers and streams. Grizzly bears are exclusively found inland, compared to other Brown Bear subspecies which are found along the coast.

What are Grizzly Bears?

Grizzly Bears are 1 of 8 different subspecies of Brown bear throughout the world. What differentiates Grizzly Bears from other subspecies is mostly their habitat and their diet. Grizzly Bears do not live along the coast like other subspecies do, such as the Kodiak Bear or the Alaska Peninsula Brown Bear. This means that these bears all have distinct diets and behaviors which differ from each other. However, all Brown Bears share common characteristics such as thick, insulating fur, a dish shaped face, large claws (about 4 inches long), short rounded ears, a small tail, fur that ranges from light brown to deep brown, and a large hump on their back. This large hump, which Brown Bears share with their Polar Bears cousins, is actually a large muscle which gives the bears extra strength for digging for food and making dens. It is also very distinctive for telling the difference between Black bears and Brown Bears. Although they look very different, the closest relative of the Brown Bears are Polar Bears. They are so genetically similar that if they breed, they would be able to have cubs. However, due to their stark difference in habitats, this almost never happens.

Fun Factoid

Did you know? Grizzly bears got their name because people thought their hair looked “grizzled”, meaning silver or white tipped.

Behavior

Grizzly Bears, like Polar Bears, spend much of their time alone, however, they often communicate with other bears from far away. They do this through sounds like grunts and growls, and especially through scent markings which they create when they rub their bodies against trees. Grizzly bears are very curious and highly intelligent with an excellent memory for returning to good food sources. Although Grizzly Bears are often seen as aggressive, they are very shy animals and like to avoid humans as much as possible. However, if they feel threatened, they are more likely to defend themselves than their Black Bear cousins. Grizzlies are quite active during the warm seasons and only sleep about 4 hours a day. The rest of the day they are out foraging for a variety of foods. During this time, they are active during both day and night, however, when winter comes Grizzly Bears, like Black Bears, will dig a den and hibernate through the harsh winter.

Fun Factoid

Did you know? Although Grizzly Bears spend much of their time alone, they will sometimes eat with other bears when they find an abundant food source.

Diet

Fun Factoid

Did you know? During the Fall, whitebark pine nuts are the most important food for Grizzly Bears in Yellowstone National Park!

Grizzly Bears, like Black Bears, are omnivores. This means they eat a combination of vegetation and meat. Grizzlies forage for a large variety of native plants including roots, berries, grasses, and fruits. As Apex predators, they also actively hunt for prey like ground squirrels, moose, elk, deer, and especially fish (like salmon). They will even eat leftover meat from already dead animals, commonly known as carrion. Grizzly Bears will often feed on what is seasonally available and try and put on as much fat as possible before winter. During their time in hibernation, when their food sources are very scarce, Grizzly Bears will lose about 15% to 30% of their total body weight. That can be equivalent to them losing over 100 lbs!

Reproduction

Grizzly Bears are normally ready to mate around 5 years old during the Spring and early Summer months. Once a male and female bear mate, they will part ways and the embryo inside the female bear will pause on development. This is a process called delayed implantation. Like all bear species, delayed implantation occurs to make sure that the female bear has enough energy and fat stored up to grow healthy cubs. During this time, the female bear will try to gain as much weight as possible before the Fall, and if she has not, she will not have a pregnancy until mating again next year. If she does have a healthy amount of fat and energy stored up, the embryo will begin its development when she enters into hibernation for the winter. After only two months, the female Grizzly can give birth to 1 to 4 cubs who are born blind and hairless. They will all stay in the warm den until Spring time. By Spring, the bear cubs will already weigh about 5 to 10 lbs with fur and teeth. Grizzly cubs stay with their mother for around 2 years where they learn everything they need to know to hunt and survive.

Fun Factoid

Did you know? The oldest Grizzly Bear to ever reproduce is Grizzly 399 who was 27 years old!

Threats

Grizzly Bears face many threats as a species, and are currently listed as threatened by the IUCN red list. As a species whose range used to span most of the North American continent and beyond, they are now mostly found in Alaska and West Canada. Unfortunately, this is due to overhunting from prior centuries, but luckily, as a threatened species, they are now protected under the Endangered Species Act. However, they still face other threats such as vehicle strikes and deforestation. They also face the threat of climate change which is causing shifts in the availability and seasonality of their food sources. In places such as Wyoming, Idaho, Washington, Montana, and Colorado Grizzlies struggle with more human caused threats due to the higher human population and developments in these areas. Luckily, there are things you can do to help the Grizzlies.

Population

Thanks to their protections under the Endangered Species Act and the efforts of scientists and researchers, Grizzly Bear populations have been steadily rising since the 1970s. Outside of Alaska in the lower 48 United States, Grizzly Bear populations had dropped to about 700 individual bears during their all-time low, but their population has been able to rise to about 1500 bears now. In Alaska and Canada, Grizzlies have stable and healthy populations with about 59,000 bears found in those areas. With rising populations and expanding territory, Grizzly Bears are slowly coming into contact with more humans and human developments. This means it is very important for people to know how to safely interact with Grizzly Bears so that bears and humans can safely coexist.

How to Help

Grizzly Bears are amazing animals and just like all wild animals, need respects and space. If you live in an area with Grizzly Bears, make sure you are always aware and cautious to stay out of the way of bears and avoid known bear habitat. Always avoid getting near any bears. Use bear-resistant storage containers and garbage containers to deter bears from thinking trash is food. Do not put toxic chemicals or litter into the environment! This can cause harm to Grizzlies and many other species, help them by disposing of waste properly.
Even if you don’t live in areas with Grizzlies, you can help! By reducing your carbon footprint, or the amount of energy you use, you can help slow climate change. This means turning off lights when you’re not using them, using less water, and if possible, walking or riding your bike instead of driving. You can also teach other about Grizzly Bears! By spreading your knowledge and teaching others about you to help Grizzlies, you can help keep their population rising!

Fun Factoid

Did you know? Just like Polar Bears, Grizzlies have an excellent sense of smell that is 2,100 times better than a human’s!