The American Black Bear
is the most widespread and numerous bear in North America where
its range extends from the northern tree limit of the Arctic far to the
south through most of Canada and the United States. In
fact, this bear is found as far south as the range of the Sierra Madre
Mountains in northwestern Mexico. The area includes 32 American
states; all the provinces and territories of Canada excluding Prince
Edward Island; and 5 Mexican States. Preferred habitat includes forests
with occasional open areas such as meadows. Excluded are areas where
heavy de-forestation has occurred. It is estimated that there are
somewhere between 400,000 and 750,000 black bears throughout North
America.
The adult bear is generally 35 to 40 inches tall when on all fours;
is 4 1/2 to 6 feet in length; weighs 125 to 600 pounds. Males within a
specific geographic area are, on average, about a third larger than
females. Fur color varies from black to a blue-white color but also
includes light brown, dark brown, cinnamon and beige. Black bears have a
heavy body, short tail, rounded ears, plantigrade feet and a hind foot
with five toes. Their curved claws are highly adapted to tree climbing
and all black bears are agile tree climbers. The black bear lacks the
distinct shoulder hump of the brown/grizzly bear. Being much quicker
than they look, the black bear has been recorded reaching speeds of over
25 miles per hour for a short distance. They are also very capable
swimmers.
Being a seeker of foods which return the highest nutritional and
protein value for the least expenditure of energy the black bear’s
diet usually consists of more than 75% of vegetable matter that includes
berries, flowers, grasses and sedges, herbs, tubers and roots, and nuts
of all kinds. The balance of its diet is supplemented with animal matter
such as decaying animal carcasses, fish, small marine animals, ants and
other insects, honey, elk and moose calves and a variety of other small
mammals such as ground squirrels and marmots.
Bears like to feed in the
cool of the evening or in the early morning but during the late summer
and early fall all bears have an imperative need to gain as much weight
as possible as the hibernation period nears. At this time black bears
will normally make very large weight gains and may forage around the
clock with only short rest periods.
 Depending
on weather climates, black bears will hibernate between four and seven
months in a den it has dug, hole up in a dense brush pile, hollow log or
tree cavity or enter a cave. Where weather is much more temperate and
the period without food available is quite short, black bears may not
hibernate or they may simply nest in a thicket or other sheltered area
for brief periods of time. While hibernating a bear’s heart rate drops
from between forty to seventy beats per minute to only eight to twelve
beats per minute and its metabolism slows down by half as an energy
saving process.
Female black bears normally mature at 3 to 5 years of age. In warmer
climates mating may take place as early as May or June: in colder
climates July or early August. The breeding season lasts two to three
weeks and the female normally mates with several males over that period
of time. After mating a process referred to as delayed implantation
takes place. The fertilized ovum divides a few times and then floats
free within the uterus for about six months with its development
arrested. Sometime around the denning period the embryo will attach
itself to the uterine wall and after a period of eight weeks the cubs
will be born while the mother is still in hibernation. The delayed
implantation process insures that the mother bear has enough fat
reserves to carry her through the winter and if that is not the case the
embryo will not implant but is simply reabsorbed by her body. Females
will normally breed every other year.
 The
number of cubs born varies from one to a maximum of four with two cubs
being the average. At birth the cubs are blind, hairless and very tiny.
They weigh from 8 1/2 to 11 1/2 ounces. In the first five weeks the cubs
will develop rapidly while nursing on their mother’s calorie rich milk
and will be able to follow their mother when she leaves the den. The
life span of black bears in the wild can be twenty-five years or more.
The American Black Bear is the one bear species which seems to have
the greatest capacity to live in close proximity to man.
 Habitat Preservation
Black bears have lost over 60% of their historical range. As human
encroachment increases, preserving large areas of undeveloped land where
bears and other animals can thrive is extremely critical. Crucial
components include adequate sources of food and water, denning sites
such as rock crevices, hollow trees and dense vegetation, contiguous
travel corridors with sufficient cover for protection from poachers,
harassment, and associated dangers from human development.
Source: The Bear Den, Don Middleton
|
