Understanding the Black Bear

Understanding the Black Bear

The black bear: omnivore extraordinaire

The American black bear (Ursus americanus) is typically a cautious creature, whose normal response to any perceived threat is to run away. They’re found throughout North America and in at least 32 U.S. states, ranging from northern Mexico up to Canada, and from the west coast of California to eastern Maine. Historically, these omnivores roamed throughout almost all of North America’s forested regions, however a growing human population has limited black bear populations to the forested areas that tend to be less densely occupied by humans.

Black bears are classified as carnivores, but “omnivore” seems to be a more fitting description since about 90% of their natural diet consists of mainly nuts, berries, young grasses and leafy forbs. The other 10% comes from scavenged carcasses and insects. They are opportunists, so when they have the chance they will also kill smaller mammals such as young deer, elk, or moose calves.

These ursines are extremely powerful animals, with jaws strong enough to crunch through deer bones, limbs that can flip over a 100-lb boulder in search of food, and short claws that allow the large bears to tear apart logs and effortlessly climb the tallest of trees. Although they are able to reach speeds of up to 35 mph during short sprints, their bodies are mainly built for strength and endurance, which allows them to set out for long daily journeys of up to 5-15 miles. Each bear is different, but they all have the same thing on their minds: food, shelter, reproduction, and avoiding danger.

What’s the difference between a wild bear and an urban bear? 

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Despite their name, black bears actually vary from shades of black to brown.

Each year, most black bears hibernate throughout the winter months. The number of days and months may vary, but in states like Colorado that endure longer winters, black bears may spend up to 7 months in hibernation. That means 7 months, over 200 days, without any food or water, and no potty breaks. It’s amazing really: their respiration drops to just one breath every 45 seconds, their heart rate drops by more than half, metabolic rates are cut by 50-60%…and even though they rarely move around, they have zero bone or muscle loss during this time!

How they stay alive for up to 7 months without food is dependent on the spring, summer and early fall months that lead up to hibernation. During late summer and fall, black bears enter this phase of intense eating, called “hyperphagia.” The bears need to gain about 3-5 lbs each day, which on the high end evens out to the animals spending up to 20 hours a day foraging so they can eat roughly 20,000 calories on a daily basis. If you think about that in terms of the average human, 20,000 calories is enough food to last the average woman for 9 days. The fat reserves gained from this constant state of foraging is necessary for their survival, and the bears won’t head out to their winter dens until they’re able to fully bulk up.

As they prepare for winter hibernation, black bears need to eat roughly 20,000 calories per day.

Black bears are extremely smart animals- biologists have placed their intelligence somewhere between dogs and primates. Their super sensitive noses allow them to sniff out a tasty meal from 5 miles away, and their excellent memories ensure they won’t forget where the food came from. Whether it be on a daily or annual basis, black bears will return to the places that provided a solid offering of food.

With the exception of moms and cubs, who are inseparable until the cubs are ready to go off on their own after their 2nd winter together, black bears tend to be rather solitary animals. However, if food sources are exceptionally abundant, they will tolerate one another and forage in groups. Otherwise, they will follow their noses to wherever food is available.


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Bears and People

Considering the amount of weight a black bear needs to pack on before winter hibernation, it’s easy to assume that these opportunists are not picky eaters! Unfortunately, their flexible diets and strong sense of smell often leads them to trouble. Some adults do die of old age or disease, but the leading cause of bear deaths tend to be from human-related activities: hunting, poaching, euthanization from conflicts, or being hit by cars.

With human communities continuing to expand into bear territories, regions throughout North America are experiencing an increased number of conflicts with black bears. To make matters more difficult each location has its own unique landscape, attractants, and attitudes surrounding wildlife; there is no “one solution fits all.” To put things into perspective, let’s take a journey to Boulder, Colorado to understand how residents are attempting to live with their wild neighbors.

All illustrations by Erin Hauer for the Bears & People Project