The three species of bears in North America are in the scientific order, Carnivora, and the scientific family, Ursidae. These oversize mammals have poor eyesight, a great sense of smell, and are the largest flesh-eating land animals in the world.
Bears are appealng, aggressive predators and generally avoid humans, so most folks never see them at close range in their native habitat, although certain signs can indicate the presence of a nearby bear. Online video cameras allow viewers to watch bears exhibit their interesting and often surprising behavior without having to be near them.
Despite their formidable presence, bears are important inhabitants of North American native forests, woodlands and Arctic shores. Relentlessly hunted in the past, their dwindling numbers have caused them to be legally protected in certain locations.
Black Bears are the Smallest North American Bears
Black bears (scientific name: Ursus americanus) are black to reddish-brown in color, although there is a “blue” version in Alaska and a white version in British Columbia. These animals are the smallest of the North American bears, but can still be up to one meter (3 feet) tall, two meters long, and can weigh up to 267 kg (587 lb).
Mating season for black bears is June to July. Offspring are born in January to February and weigh little more than 200 g, or about half a pound.
The North American Bear Center in Ely, Minnesota, has a video camera that allows online viewers to observe adult black bears overwintering, and to watch the birth and development of their young.
The Louisiana black bear, a subspecies of Ursus americanus, is found in Louisiana, Mississippi and Texas, and is designated as Threatened, under the Endangered Species Act.
Grizzly Bears are the Largest in the World
Grizzly bears (Ursus arctos) are brown-colored to yellowish, with white-tipped hairs, giving them a “grizzly’ appearance. They have a huge hump above the shoulders and a slightly concave, or indented, face, features that distinguish them from other bears.
Grizzlies (also called brown bears) are up to 1.3 meters tall (4 feet) and 2.13 meters (7 feet) long. They can be as much as 700 kg (1700 lb), making them the most massive terrestrial carnivores in the world.
Mating season for grizzlies is June to July. Offspring are born in January to March, with the newborns weighing about 450 g (1 lb).
Like black bears, grizzlies love to scratch their backs on trees, which, as this United States Geological Survey (USGS) Grizzly Bear Project video shows, can be a remarkable sight.
In the United States, the grizzly bear is found in Idaho, Montana, Washington and Wyoming, and is listed as Threatened, under the Endangered Species Act.
How to Tell When a Bear is Near
In black bear or grizzly (brown bear) country, certain signs indicate a nearby bear:
- bear scat (feces), which looks like that of a large dog, except for the presence of berries, animal hair, insects, seeds, grass, or nuts.
- large, human-like footprints, with the biggest toe in the center, and claw marks, if the ground is soft.
- trees scarred with claw scratches, tooth marks and rub marks; hair stuck in the bark
- trees stripped of bark, worn smooth by rubbing, and with tooth marks above 2 meters indicate grizzly presence
- uprooted or overturned logs or rocks
- torn up berry bushes, anthills or small mammal burrows
- dead animal skins with head and feet still attached
- a shallow hole containing the carcass of a large animal, covered with tree branches or earth, is a sure signal that a grizzly bear is very close by.
Polar Bears are Built for Buoyancy
Polar bears are found in nature only at the northernmost regions of North America, often on floating ice. They have white fur, a black face, a long neck and legs, and tiny ears. The largest individuals can measure up to 1.2 m (4 ft) high, 3.4 m (11 ft) long and weigh 500 kg (1,100 lb).
Breeding season is April to May, every two or three years. Offspring are born the following November to January and weigh about 900 g (2 lb).
The hair of a polar bear is hollow and waterproof, allowing it to float easily, and it can swim up to 10 km (6.5 mi) per hour. It has an outstanding sense of smell, by means of which it can detect prey under snow or ice. The most carnivorous of the three bears described here, polar bears will hunt day or night.
Signs of a polar bear include seal remains, often accompanied by gulls circling overhead, or fox prints; big, dark, dog-like feces; and footprints that are up to 33 cm (13 in) long by 23 cm (9 in) wide, with few claw marks.
Although their inhospitable habitat makes is difficult to see polar bears in the wild, even by remote video, the San Diego Zoo has a polar bear cam that allows online viewers to observe polar bears live: http://www.sandiegozoo.org/polarcam/index.html.
In the United States, polar bears are designated as Threatened, under the Endangered Species Act.
References:
Elbroch, M. 2003. Mammal Tracks and Signs: A Guide to North American Species. Mechanicsburg, PA: Stackpole Books. 778 pages.
Environment Canada Web site: http://www.ec.gc.ca/default.asp?lang=En&n=FD9B0E51-1
Myers, P., R. Espinosa, C. S. Parr, T. Jones, G. S. Hammond, and T. A. Dewey. 2008. The Animal Diversity Web (online). http://animaldiversity.org.
NatureServe. 2009. NatureServe Explorer: An Online Encyclopedia of Life [web application]. Version 7.1. NatureServe, Arlington, Virginia. http://www.natureserve.org/explorer.
United States Fish and Wildlife Service Endangered Species Program Web site: http://www.fws.gov/endangered/wildlife.html.
Whitaker Jr., J. 1997. National Audubon Society Field Guide to North American Mammals. Revised edition. New York: Alfred A. Knopf. 937 pages.
Marie Lawrence - Marie Lawrence is an environmental biologist and science writer with more than a decade of experience working to preserve wildlife and ...
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