Description:
The American Black Bear is one of two species of bears originally occurring in Kansas. It can be distinguished by: 1) large, heavy body and long legs, 2) very short, well-haired tail, 3) five toes on each foot, each toe with a short curved non-retractible claw, 4) facial profile which is straight to somewhat convex, 5) medium-sized, somewhat elongate ears, 6) thick, glossy fur which varies in color (black was most common in Kansas), 7) yellowish brown muzzle, and 8) occasionally having white patches of fur on its throat and chest. Adults may attain the following dimensions: total length 1270-1780 mm; tail 80-125 mm; hind foot 190-280 mm; ear 135-150 mm; weight 100-225 kilograms.
Natural History:
American Black Bears often are nocturnal, but may be active during the day, with activity peaks during early morning and late afternoon. In spring and autumn, black bears tend to be more crepuscular than during the summer. When inactive, black bears den in road culverts, natural cavities, and hollow logs and trees. The den entrance may be well above the ground; the entrance to one den was thirty meters up a tree. Home range in this mammal varies with sex, locality and time of year. Males use a much larger (29-32 square kilometers) area than females (1-7 square kilometers), but daily movements rarely cover more than a few kilometers. Evidence indicates that individuals of the same sex do not have overlapping ranges, but no aggressive defense has been reported. Population densities vary from one black bear per 5.5 square kilometers to one per 1.6 square kilometers. In favorable areas these population densities may be locally higher, and in marginal habitat much lower. Dispersing individuals may travel over 145 kilometers searching for a suitable area, but typically move much shorter distances. Once they establish a range they are usually sedentary for the remainder of their lives.
In autumn black bears begin to store fat and, usually in December, enter a winter den. The den is frequently in a site with heavy ground cover, and bedding material is sometimes gathered. Black bears, unlike some ground squirrels and rodents, are not hibernators. Unlike true hibernators, black bears are relatively easily aroused from their winter dormancy. Dormant black bears have decreased heart rate and respiration, but their body temperature declines very little. They remain dormant from two to four months during the year, even when the weather is mild.
A vast majority of the diet of the black bear is vegetable material. It is an opportunistic feeder, although grasses, fruits (apples, grapes, strawberries, and persimmons) and nuts make up to 96 percent of its diet. Animal matter eaten by this mammal consists of insects, small rodents, birds, and carrion.
The black bear breeds from late May through July, with a peak in mid-June. Following breeding, males and females separate. When embryos within the pregnant female reach an early stage, development ceases, resuming in November or December. In January, after a total gestation period of 210 to 220 days, one to five (average two) cubs are born blind, covered with a fine coat of fur, and weighing 235 to 240 grams. By February the cubs are about 400 millimeters long, weigh almost a kilogram, and are covered with short, black fur. Their eyes open after about 25 days. They first leave the den with the female at two months of age, and are weaned by six to seven months. From spring until late autumn the female and cubs move throughout a home range. By eight months of age, young male cubs weigh about nine kilograms and females weigh about seven kilograms. The cubs usually stay with the female during their first winter, and disperse before the female breeds the following May. As a result, females may breed in alternate years unless the young of their previous litter do not survive. Black bears become sexually mature at three and a half to four and a half years of age; females may reproduce until they are 20 years old.