California Black Bear

Ursus americanus californiensis

Physical Characteristics

The coat of a black bear is shaggy and usually black but it can also be dark brown, cinnamon, yellow-brown, and grey-blue depending on location. Eyes are brown (blue at birth). Skin is light gray. The black bear is approximately 4 to 7 feet from nose to tail, and 2 to 3 feet high at the withers. It has small eyes, rounded ears, a long brown snout, a large body, and a short tail. Males weigh an average of 150-300 lbs. Black bears have 5 toes, each with a well-developed claw, on both front and hind feet, and teeth adapted for feeding on both plant and animal matter.

Black bears have strong powerful legs with large paws. They are expert tree climbers and have an excellent sense of smell.

Habitat

Black bears have lost over 60% of their historical range. They historically occupied nearly all of the forested regions of North America, but in the U.S. They are now restricted to relatively undisturbed forested regions. Black bears are adaptable and live in a variety of habitat types. They are mainly found in forested areas with thick ground cover and an abundance of fruits, nuts and vegetation. During the winter they hibernate in dens that they have built. They will build their dens in tree cavities, under rocks or logs, in banks or caves, culverts and in shallow depressions.

Diet

California Black Bears are omnivores. 95% of their diet is plant based. Black bears mainly feed on vegetation including herbs, grasses, roots, buds, shoots, honey, nuts, fruit, berries and seeds. Occasionally they will also eat fish, small mammals, insects & insect larvae, carrion and garbage. Bears commonly consume ants and other insects in summer, but prefer nut crops, especially acorns, and manzanita berries in the fall.

 Behavior

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. Some bears are active mainly at night to avoid people or other bears. 

Not all of the black bears in our region are thought to go into hibernation in the strictest sense of the term, but since no studies have been done on local populations, it is hard to know for certain. Bears inhabiting chaparral at lower elevations are not as affected by cold temperatures and lack of food as those that live in the coniferous forests. However, it appears that a majority do undergo a period of prolonged inactivity, and those that give birth will usually den up during winter months.

Because of their very short tails and long hair, bears cannot use tail or torso to send signals through body language as some other creatures do. This may explain why head, neck and mouth are used so much to communicate. Walking with head held below the shoulders is likely to result in some type of aggressive behavior. A whole range of facial and mouth expressions are used to intimidate one another including snarling, opening and closing the mouth rapidly while salivating, bearing teeth and making chomping (clacking) noises often indicate an agitated bear. A bear will sometimes bluff-charge an intruder by running full speed at the intruder and stopping just short. This is usually in a strong signal for the intruder to leave the area.

Black bears can sprint up to 35 mph and they are strong swimmers.

Breeding

Black bears are solitary animals except for mothers with cubs, during the breeding season or when they come together at feeding sites.

Black bears mate during the months of June and July. Cubs are born in January or February after a gestation period  of 215 days. There are usually 2-3 cubs per litter, but litter sizes can be  as large as 5. The cubs are born in a den while the mother is hibernating. At birth the cubs weigh between 200 and 450g (7 – 16oz). They are born blind, with no fur and they will remain with their mother in the den until spring. The cubs are weaned at 6 – 8 months old. They usually stay with their mother for about 2 years so they can learn how to hunt and survive. They reach sexual maturity when they are between 2 and 5 years old.

Black bears can live to 30 years in the wild. They usually live for only about 10 years, due to encounters with humans.

Predators

Other than humans, black bears have few predators – bobcats, cougars, and coyotes occasionally attack cubs.

References

naturemappingfoundation.org/natmap/ca/facts/mammals/american_black_bear.html

www.tahoewildbears.org/black_bear_facts.htm

www.dfg.ca.gov/wildlife/hunting/bear/biology.html