Mammals
American Black Bear
Ursus americanus · also called American black bear, black bear
The American black bear is the bear most people will ever meet — the one raiding the campsite cooler, crossing the mountain road, or ambling through a suburban yard. It is the most numerous bear on Earth, and for its size one of the least dangerous large animals in North America.
Overview
American black bears live in forested country across most of Canada, the United States, and northern Mexico — from Alaskan rainforest to Florida swamp to the pine woods of the Sierra Madre. They need tree cover and a seasonal food supply, and within that they are highly adaptable, tolerating farmland, suburbs, and city edges. They are mostly solitary, crepuscular, and excellent climbers, and each holds a large home range.
Mostly a vegetarian
Despite the fangs, roughly 85% of a black bear’s diet is plants — berries, nuts, acorns, grasses, roots — supplemented with insects, honey, carrion, fish, and the occasional deer fawn. Bears spend late summer and autumn in hyperphagia, eating up to 20,000 calories a day to build the fat they need for winter.
Not always black
Coat colour is genetically variable: black in the humid east, but often cinnamon, brown, or blond in the drier west, plus the cream “spirit bear” of coastal British Columbia and the silvery “glacier bear” of Alaska — all one species.
Winter denning
Black bears den for up to seven months without eating, drinking, or passing waste, their temperature dropping only a few degrees — a metabolic feat studied for human medicine. Cubs are born in the den in mid-winter, tiny and blind, and nurse until spring.
Rarely a threat
Black bears are timid and usually flee. Fatal attacks average about one a year across the continent despite tens of millions of encounters, and defensive attacks by mothers are almost unheard of (unlike grizzlies). The real issue is food-conditioned bears near people, which become bold and are often killed — which is why securing garbage and feeders matters.
Status
The American black bear is Least Concern and increasing, with 800,000–950,000 animals — more than all other bear species combined.
American Black Bear: common questions
How dangerous is an American black bear?
Much less than its size suggests. Black bears are naturally timid and generally avoid people; the standard response of a startled black bear is to flee, climb a tree, or bluff-charge and then retreat. Fatal attacks are very rare — on the order of one per year across all of North America, despite tens of millions of bear–human encounters annually — and most predatory attacks involve lone bears in remote areas, not mothers with cubs (a common misconception; defensive attacks by black bear mothers are almost unheard of, unlike grizzlies). The real problem is food-conditioned bears near campsites and homes, which become bold and destructive and often end up being killed. Standard advice for a black bear encounter is to make yourself look big, make noise, and back away slowly, and to fight back if actually attacked.
Why are some "black" bears brown, blond, or white?
Coat colour in this species is genetically variable and not tied to subspecies. In the humid forests of the east, nearly all black bears are black. Moving west and into drier, more open country, brown, cinnamon, and blond bears become common — a lighter coat may help with heat and may make a bear on open ground look more like a small grizzly, deterring predators. On a few islands off British Columbia, a recessive gene produces the cream-coloured "spirit bear" or Kermode bear in perhaps 10 to 20 percent of the local population, and a separate mutation near Yakutat, Alaska, produces the rare silvery-blue "glacier bear." All are the same species.
Do black bears really hibernate?
They den and become dormant for the winter, but biologists debate whether it counts as "true" hibernation. Unlike a hibernating ground squirrel, whose body temperature falls close to freezing, a denning black bear's temperature drops only about 5 to 6°C, and it can rouse and defend itself within minutes. What is remarkable is the metabolic feat — for up to seven months the bear does not eat, drink, urinate, or defecate, recycling its own waste products, and it emerges with almost no muscle or bone loss despite months of inactivity. Researchers study this for insights into osteoporosis, kidney failure, and long-duration spaceflight. Pregnant females also give birth and nurse cubs during this time.
How can there be so many black bears near where people live?
The black bear is a forest generalist that has adapted well to the human-modified landscape of North America. It needs tree cover and a seasonal food supply, both of which regrew across the eastern US as farmland was abandoned in the 20th century, and it tolerates suburbs, farmland, and even the edges of cities as long as there is forest nearby. Regulated hunting replaced unregulated persecution, populations recovered, and the bear expanded back into states where it had been wiped out. Today black bears live within a short drive of most people in the US and Canada, which is why "bear in the backyard" stories are common and why securing garbage and bird feeders matters.