Bears | Nature Adventure

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Biology

Bears are large, furry mammals found all over the world. From the Americas to Asia, and even the arctic, bears are highly diverse in their appearances, environmental adaptations, and even their diets!

In North and South America, there are four bear species— brown bears (Ursus arctos), black bears (Ursus americanus), polar bears (Ursus maritimus), and spectacled bears (Tremarctos ornatus)!

Despite their names, black and brown bears can have a variety of fur colors, anywhere from blond to black. Black bears as a species have longer ears, are shorter than brown bears, and are found further south than brown bears often are. These bears are sometimes a problem in cities, since they act like large raccoons, and love to break into people's trash. Despite being small for a bear, they can still be very dangerous, and you should never intentionally feed a bear by hand or by leaving food out where they can find it!

Bears cannot always be rehabilitated back into the wild, and feeding them might end up with them, or yourself, getting seriously hurt. You might see signs that say "A Fed Bear Is A Dead Bear", and they're right! It is much kinder to let them find their own food and not learn to rely on humans, as fatal accidents often occur when bears and humans live too close together.

Another name for brown bears is the "grizzly bear", and they are the second largest bears in North America. These bears are big, fluffy, and are popular on the internet for their intelligence and cute faces! They are most famous for catching salmon in the northern rivers as the fish migrate to spawn. Families of bears will gather at the river to socialize and eat huge amounts of salmon in order to bulk up their weight before hibernation. During the winter, grizzly bears won't eat at all as their bodies slow down their metabolism, and they spend most of their time sleeping in dens under the snow. They will slowly lose all that weight gained during the fall, and wake up in spring ready to hunt and eat fresh berries.

The largest bear of all living species today, and in fact the largest carnivore on Earth, is the polar bear. These bears live in the Arctic Circle, and around 60% of their population is in Canada. But polar bears are actually found in a total of five countries overall: the United States (in Alaska), Canada, Russia, Greenland, and Norway (in Svalbard). As the climate changes and polar ice starts to melt, polar bears are starting to be found south of the Arctic Circle, and can even create hybrid species with brown bears, called grolar bears! Polar bears have so many unique adaptations for their environment that it's almost impossible for them to survive anywhere else. Additionally, polar bears are the only species of bear that actively hunt humans as prey, making it more difficult to live around them without conflict. Despite this, they are important for maintaining balance in the Arctic ecosystem as they eat other predators like seals and walruses. They've even been known to eat small whales!

The spectacled bear is South America's only native bear species. These are rarely seen and only live in the high Andes mountains. Despite being small in size today, these bears are the last living relatives of the giant short-faced bears that went extinct at the end of the Pleistocene Era. Their ancestors were around 11 feet tall when standing upright! But today, spectacled bears are only around 2 feet tall when standing on all fours. Their name comes from the white markings around their eyes, and they're one of the least-aggressive bear species towards humans, being mostly herbivorous.

Ecological Importance

Bears are omnivores, meaning they are adapted to eating both plants and animals. Even pandas have the teeth needed for eating meat! But being able to eat any type of food makes bears extremely adaptable to almost any environment. In wildlife science, we call animals like that a “generalist”.

When bears eat berries, they eat them by the thousands. This helps spread berry seeds far away from the original plant, letting new berry bushes grow deeper in the forest without competition. When bears eat fish, they bring the carcasses and nitrogen inland, feeding nutrients to plants that would otherwise never get them. In this way, bears help the entire forest grow bigger and healthier, kind of like a gardener!

Unfortunately, like us humans, bears also love junk food. One of the most common problems with bears is that they’re both big enough and smart enough to get into our trash cans. Bears may look cuddly and cute, but they can be a serious threat to people’s safety; they’re big, dangerous animals that might lash out if they’re afraid or feel threatened. For their safety and ours, it’s important that cities near bear populations establish good boundaries and rules around how to dispose of trash, and that citizens like you do your part in maintaining cleanliness in your cities!

Did you know?

Bears are more closely related to canines, like wolves and dogs, than you might think!

The suborder Caniformia includes canines, bears, foxes, raccoons, and mustelids like ferrets and badgers. The bear family Ursidae split off from their last-known common ancestor with dogs and wolves— a genus known as the miacis— around 62- to 32-million years ago. That was a long time ago!

As a comparison, the last known common ancestor between monkeys and apes existed around 25-million years ago; and as humans, we last had a common ancestor with chimpanzees around 9-million years ago. Despite sharing a common ancestor, humans and chimpanzees are very different species today— and the same can be said for bears and dogs. Though, since they share a suborder, it's almost like they're distantly related cousins!

Unfortunately, bears and dogs don't get along well. Dogs will often fight with bears to protect their land and owners, so it's important to keep them on a leash when visiting the forest. Remember— when you go hiking, you're visiting a bear's home! Be a nice guest, and don't let your pets fight with the local wildlife.

Keep your distance from bears, and remember that no matter how cute and dog-like they might seem, they are still wild animals. You should never try to feed or pet a bear.

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