American Black Bear

As their name suggests, black bears are known for being black in color with a lighter brown muzzle. However, this coloration is most common in the eastern half of their range. Black bears can also be cinnamon, dark brown, blonde, and in small areas of British Columbia or coastal Alaska, white or blue-gray. This range of colors likely helps them blend into their habitat.

Because of the overlap in color variation, black bears are frequently confused for brown bears. There are a few differences you can use to tell them apart. The side profile of their muzzle is straight or convex, as opposed to the brown bear with a concave muzzle. They have a rump that sits higher than their shoulders and lack the prominent shoulder hump that brown bears have. Black Bears are also the smallest of the three North American bear species, weighing around 100 to 500 pounds, with females staying in the lower range.

Black bears have prominent ears that are twice as good as human ears. With curved claws, Black bears are designed for tree climbing. They communicate by scent-marking which includes rubbing, clawing, and biting tree trunks.

American Black bears live across North America in temperate forests. They usually stick to areas with thick understory vegetation. Historically, they were quite common throughout Canada, the USA, and northern Mexico. However, they have lost much of their southern range.

Black Bears are considered apex (or top) predators, but have on occasion been killed by other bears, wolves, and mountain lions. Because they are top predators, the ecosystem relies on them. Black bears help manage population control of certain species. Since they also act as scavengers on occasion, they play an important role in removing diseases from the ecosystem. They also help return nutrients to the soil during their kills and within their fecal matter. Because of all these roles, they help increase species diversity where they are found.

Black bears are omnivorous and have a widely variable diet based on seasonal and regional availability. During the early spring, their diet consists mainly of herbs, buds, young leaves, nuts, and the occasional carrion (carcass or other decaying animal matter). As summer comes along, they add in fleshy fruits and berries, and in fall they begin to eat more nuts and seeds. Only a small part of their diet consists of meat, usually insects. When they do eat larger vertebrate prey, it is usually in the form of carrion. Very rarely, black bears hunt young deer, moose, and fish.

Black bears are very intelligent and can quickly learn to associate humans with food. This can be very dangerous, not just for people, but for the bears too. Being in close contact with people puts them at risk of being hurt both directly and indirectly by us. They are attracted to campsites, garbage bins, and cars. It’s important for us to do everything we can to keep bears out of our trash to help deter them from becoming too habituated to human presence.

Black bears are generally diurnal, but they can be crepuscular, active during dawn and dusk. In warmer environments, they tend to avoid the midday heat and any human activity. Black bears are generally solitary and are usually only seen together when a mother is raising her cubs, or when a male and female get together for a few days during mating season. Males have very large ranges that can be up to 77 square miles and overlap with several females’ ranges. Females generally have much smaller ranges of 4.6-19.3 square miles. When mothers are raising their cubs, they will sometimes go on long treks outside their home ranges to show their cubs seasonal food like special berry patches or salmon runs.

Black bears adhere to a specific seasonal regimen. The mating season takes place in early summer, around May through July. Males and females will spend up to 3-5 days together. However, females are able to delay egg implantation if necessary until they have enough fat storage to sustain a pregnancy. Then, in the later summer, they undergo a period of time called hyperphagia where they try to gain as much weight as possible. During hyperphagia, bears can spend up to 20 hours a day foraging for food to prepare for the winter. Black bears do not undergo true hibernation and instead experience a similar state of inactivity called torpor. Torpor can begin anywhere between October and December, and end between March and May. Females will generally give birth during this time in January. Her cubs will nurse throughout winter and emerge with their mother once she wakes in the spring.

Cubs will stay with their mothers for their first two years of life. She is fiercely protective over them, especially because male black bears will not hesitate to attack and kill the cubs in order to mate with the mother. Cubs must undergo a second winter with their mother before they are ready to disperse and leave their mother’s territory.

American black bears are listed as Least Concern on the IUCN Red List. Black bears tend to be unaggressive, which has led to much more human tolerance. Because of this, black bears have been able to obtain more human-related food. It is easier to find and usually higher in calorie count. In human dense areas black bears have been able to mature faster and produce more offspring, which has led to an increase in their overall population.

Unfortunately because of this, black bears face incredible human-wildlife conflicts while living near people. This issue is largely due to humans not taking the proper care of their food waste. When bears become too habituated to humans, there is risk for depredations.

• The seasonality of black bear behavior is thought to be triggered by the amount and angle of sunlight the bear experiences. This phenomenon is called photoperiodism, the same mechanic that cause deer to grow antlers.
• American black bears are the only bear species whose population numbers are increasing throughout their entire range.
• Despite their physical similarities and geographic closeness, black bears are not very closely related to brown bears. Instead, the American black bear’s closest living relative is the Asiatic black bear.

In 2017, Oakland Zoo worked with the California Department of Fish and Wildlife (CDFW) to rescue a family of black bears that began entering neighborhood homes in search of food, creating a serious human-wildlife conflict. The mother and her cubs were deemed unreleasable because of their habituation to human presence, including desensitization and reliance on human food. Thankfully, the Oakland Zoo was able to provide them with a second chance at life on the California Trail.

Take a trip on our gondola to visit Cambria and her two, now grown, sons, Kern and Tejon. Cambria is estimated to be born in 2011 and is the lightest colored and smallest of the three. She still takes on the motherly role and is very much in charge of her sons. Kern and Tejon were both born in 2017. They are difficult to tell apart visually, but have distinct personalities. Tejon is a big mama’s boy and still cuddles with Cambria and follows her around like a cub. Kern is more independent and cautious. He is very in tune with the surrounding environment.

Oakland Zoo partners with and supports the Bear League, based in Tahoe. Bear League educated the community on how to live sustainably with Black Bears. They respond to bears in human territory, and help provide the community with a 24 hour hotline for bear sightings and encounters, as well as rentable bear deterrent mechanisms.