BASIC BEAR FACTS
BLACK BEAR FACTS
For more information see www.bear.org
Size and Appearance
General: Black bears are 4 to 7 feet from nose to tail, 2 to 3 feet high at the shoulders, and have small eyes, rounded ears, a long snout, a short tail, and light gray skin. Their fur is shaggy or sleek, depending upon the season.
Compared to grizzly bears: Black bears average smaller than grizzly bears, have a smaller shoulder hump, and a less concave facial profile. Their claws are smaller and more tightly curved for climbing trees. Their fur is less shaggy. Their ears are longer, smoother, and more tapered. They have a furred rear instep, unlike the grizzly.
Fur color: Black bears come in more colors than any other North American mammal. They are almost always black in eastern populations but are brown, cinnamon, black, or occasionally blond in western populations. Other color phases are white and bluish-gray as shown in the exhibit on color phases.
Individual black bears can be recognized by:
-
the muzzle color and pattern of black, brown, and blond fur
-
the shape and shade of brown of their eyebrow patches, if present
-
the shape and extent of white chest patches, if present. These range from a few white hairs to conspicuous patches
Cub traits: Cubs’ blue eyes turn brown within a year. Brown patches on the front and back of their ears usually disappear within a year.
Vision: Bears see in color and have good vision close-up. Their distance vision (over two hundred yards) has not been tested.
Hearing: Exceeds human frequency ranges and probably twice the sensitivity.
Smelling: Their smelling ability is extremely good. The limits are untested. Their nasal mucosa area is about 100 times larger than in humans.
Intelligence: Large brain compared to body size. One of the more intelligent mammals. Navigation ability superior to humans. Excellent long-term memory. Can generalize to the simple concept level.
Vocalizations: Usually silent (except in movies in which sounds are dubbed in). A variety of grunts in amiable situations. Loud blowing noises when frightened. Clack teeth when frightened. They use a resonant, humanlike “voice” to express a range of emotions from pleasure to fear. Does not threaten by growling (except in movies). In story-telling, any sound a bear makes is called a growl.
Swimming ability: Good. Speed and distance limits are untested. Can swim at least a mile and a half in fresh water. One swam more than 9 miles in the Gulf of Mexico. Can swim to island campsites.
Running Speed: Lean bears can exceed 30 mph. Can run uphill, downhill, or on level ground. Fat bears in winter coats overheat and tire quickly.
Daily Activity Period: Most bears become active a half-hour before sunrise, take a nap or two during the day, and bed down for the night an hour or two after sunset. However, some bears are active at night to avoid people or bears.
Preferred Foods: Nuts, acorns, fruit, insects, succulent greens. Meat and less succulent greens are eaten when preferred foods are scarce. A scarcity of preferred foods can result in failed reproduction, stunted growth, failure to add optimal amounts of fat, and death of young bears, especially cubs.
Do Bears Hibernate? When hibernation was defined simply in terms of temperature reduction, bears were not considered hibernators. New knowledge of hibernation processes has led biologists to redefine mammalian hibernation as simply a specialized, seasonal reduction of metabolism concurrent with the environmental pressures of scarce food and low ambient temperatures. Black bears are now considered highly efficient hibernators. While it was once thought that they sleep for months without eating, drinking, urinating, or defecating, researchers have found through observing inconspicuously installed den cameras that bears do wake up, stretch, yawn, move about to find a corner of the den in which to urinate or defecate, chew on their footpads, eat snow, take a look outside the den entrance, etc. Black bears have insulative pelts and as a result, bears’ body heat is lost very slowly, enabling them to cut their metabolic rate in half and still make it through winter, maintaining temperatures above 88 degrees – within 12 degrees of their normal summer temperature. Mothers wake up before giving birth, typically in mid to late January, and take excellent care of the cubs in the den, licking them clean and responding to every cry for warmth and milk.
Length of Hibernation: The length and depth of hibernation is genetically programmed to match the regional norms of food availability. Hibernation is deeper and can last over seven months in the northern portion of the black bear range where abundant, high quality food is available only from May through August. There, some bears hibernate so deeply, especially the leaner bears after a summer of unusually scarce food, that a person can jostle them for several minutes before they wake up. However, in southern states where food is available year-round, some do not hibernate at all, and those that do are easily aroused. Lean females cannot bring their fetuses to full term and do not give birth.
Potential Longevity (lifespan): Black bears can live 21-33 years or more if they are not killed.
Causes of Death: Very few adult bears outside of national parks die of natural causes. Nearly all adult bears die from human-related causes. Most are eventually shot. A few are killed by vehicles. The average age of death in hunted populations is three to five years of age. Bears less than 17 months old sometimes die from starvation, predation, falls from trees, and other accidental causes. Very few die of disease.
Core Home Range Diameter: Typically: Yearlings: 1-2 miles. Adult females: 2-6 miles. Adult males: 8-15 miles. Excursions to 126 miles recorded.
Ideal Habitat: Black bears like large forests with many different kinds of fruits and nuts. Small sunny openings within the forest provide many kinds of food for the bears. Lowlands and wetlands provide tender and juicy vegetation. Streams and woodland pools provide water for drinking and cooling. Mothers with cubs like large trees (over 20 inches in diameter) with furrowed bark (like white pines or hemlocks) for bedding sites. These trees are safest for small cubs to climb.
Living with Bears: Many people are moving into black bear habitat. The bears’ future depends on how well we understand and tolerate them.
Long-Term Problem: Magazines and movies have given black bears an unrealistically ferocious image, causing people to fear them excessively and kill them unnecessarily. There are many misconceptions about black bears.
Greatest Misconception: The greatest misconception about black bears is that they are likely to attack people in defense of cubs. They are highly unlikely to do this. Black bear researchers often capture screaming cubs in the presence of bluff-charging mothers with no attacks.
Defense of Cubs is a Grizzly Bear Trait: About 70 percent of human deaths from grizzly bears are from mothers defending cubs, but (with one possible exception) black bear mothers have not been known to kill anyone in defense of cubs.