A mother bear with 2 cubs on Kamchatka.
Photo by Igor Shpilenok.
Population and Distribution
Brown bears are one of the most widely distributed large carnivores
in the world. The Kamchatka peninsula was once entirely populated with
brown bears, and in remote protected areas is still home to the highest
recorded density of brown bears on Earth. Increasing human access,
through road development to expand mining and mineral exploration, is
fragmenting the once continuous bear population, and Kamchatka brown
bears are now becoming rare in some regions close to human settlements.
Population estimates for the entire Kamchatka peninsula range from
10,000-14,000 bears in an area about the size of California. Population
counts for the region are based largely on the casual observations of
hunters and forest workers and are scientifically questionable. More
than a decade has passed since the last aerial survey of the region, and
there is a desperate need to redefine survey methods to monitor the
long term trends in the bear population.
Male Kamchatka brown bears can reach a weight of 700 kilograms, and
are among the largest bears in the world. Their large physical size is a
result of their access to rich food sources like salmon, pine nuts and
berries. Maintaining body weight is crucial to survive the long period
that bears spend sleeping in their winter dens (up to 6 months on
Reproduction and Life Span
Female brown bears in Kamchatka can begin to reproduce as early as 4
years of age and typically have litters of 2-3 cubs. WCS research has
shown that some female bears with cubs do not approach salmon streams,
to avoid risking their cubs being killed by another bear. By staying
away from the salmon streams the females reduce the risk of cub
mortality, but are also forced to survive on less rich food sources.
Gaining enough weight to survive the winter is critical for female brown
bears and their offspring. Cubs are born in the dead of winter in dens
where the female is hibernating. Pregnant female bears that enter the
den poorly nourished will often not be able to support their offspring,
and the pregnancy will end before the birth of the cubs. The size of
male brown bears is related to their social status and access to food
and mates. Female bears must be induced into estrus, which means a male
bear may have to follow a female bear for weeks until she is receptive
to mating. During this time the male bears must fight off other male
suitors. Females can produce offspring from different males in a single
The area that a bear requires to fulfill all of its life requirements
varies depending on habitat type and food sources available. In areas
very rich in salmon, WCS research has shown that bears will maintain a
home range as small as 12 sq km over the entire year. In areas where
salmon and other food sources are scarce, however, home ranges can be as
large as 1100 sq km. Data from GPS-collared bears showed that bears
made movements of up to 65 km and crossed Kamchatka's central mountain
range to access different salmon runs, crossing into different hunting
leases and even leaving protected areas.
Kamchatka has some of the best brown bear habitat in the world. The
highest concentrations of bears occur along streams during salmon
spawning. Dense dwarf Siberian pine swales as well as expansive berry
tundras can be rich feeding grounds for bears. Coastal sedge meadows and
lush vegetation fed by heavy rainfalls are a bear “salad bar” when less
rich food sources are available. In the fall bears in Kamchatka will
usually excavate dens at higher elevations on south-facing slopes.
Salmon including: Pink, Sockeye, Coho, Chum, King, Cherry as well as
char. Dwarf Siberian pine nuts, blue berries, crow berries, cranberries,
mountain ash berries and others. Bears also feed on a wide variety of
vegetation usually in the early summer. In some regions bear will hunt
sea otters or be fortunate enough to find dead sea mammals like seals
and even whales along the shore.
Read about threats to Kamchatka brown bears.