|
Black bears may be both predator and
prey. Black bears can be prey for other predators, particularly grizzly
bears. In addition, black bear cubs and adult females can be cannibalized by
male black bears. Black bears can be significant predators of young deer,
elk, moose and caribou in some areas of North America, particularly where
they do not have competition from other predators, such as grizzly bears and
wolves.
The great variation in the percentage of moose calves killed by black bears
in Alaska can be attributed to the different densities of black bears,
grizzly bears and wolves.
The role of black bears in regulating or limiting ungulate populations is
complex and depends on many factors, including the presence of other
predators. Black bears rarely kill adult moose, although 15% of the adult
caribou that died in a study near Quesnel Lake, BC were killed by black
bears. Moose have several strategies to offset the impact of predation on
their young. Female moose tend to all give birth at about the same time,
which reduces the risk that predators will be able to kill all or even most
of the young. Moose also have high twinning rates and low adult mortality.
There are also other overriding factors that control moose populations,
including disease, habitat quality and quantity and weather.
|