Virtual Viewing
Inside Passage Audio Guide
Black and Brown Bears
Audio
Download Episode: Black and Brown Bears (MP3 file 2,831 kB)
Transcript
Bears
Both black and brown (grizzly) bears are found in Southeast. Only brown bears are found on Admiralty, Baranof , Chichagof and Kruzof Islands, and with rare exceptions only black bears are found on most of the other Southeast Islands. They tend to be segregated in Southeast Alaska, but some overlap occurs on the mainland and around Glacier Bay. Their distribution is likely related to how they colonized Southeast Alaska following the retreat of the glaciers 8,000 to 10,000 years ago.
Black bears are about two and a half feet tall at the shoulder and are about five feet long. They are considerably smaller than brown bears and lack the brown bears' distinctive shoulder hump. Black bears average about 200 pounds, but some older bears may reach 300 to 350 pounds. Brown bears average between 500 and 900 pounds, and some older males can reach 1,400 pounds.
Like humpback whales, bears spend six to eight months a year feeding heavily, and the rest of the year fasting. Whales store this food energy as blubber and bears store it as fat, and summer in Alaska is a critical feeding time.
Bears are omnivorous, eating meat and vegetation. They feed on berries, a wide variety of green vegetation, carrion they scavenge, and salmon when it is available. Bears will dig up marmots, till up meadows for roots, and tear apart logs for insects and grubs. They opportunistically prey on deer and moose, especially fawns and calves in the spring.
Don't look for bears in the fall and winter; they are tucked away in dens hibernating. Hibernating bears are biological wonders. They don't suffer bone loss, muscle atrophy or bedsores the way an inactive, bedridden person would. They don't eat or drink water, but their nutritional needs are met. Bears lose about 20 percent of their body weight during hibernation, and regain this over the summer. Physiologists and medical researchers are studying bears for insights into osteoporosis, kidney disorders and human sleep.
Bears are one of the few animals to gestate young - a high-energy-demand state - in hibernation while fasting. Bear cubs are born mid-winter, tiny and blind, and nurse through the winter, sharing their mother's fat reserves through her rich milk. Litters range from one to four cubs; two is most common. Mother bears are famously protective of their cubs. Cubs typically separate from their mother as two-year-olds. Some brown bear cubs stay with their mother for three to five years.
Brown bears live to be about 24 years old on average. Except for females with cubs, they are usually solitary animals and avoid other bears. Exceptions occur where food sources are concentrated, such as salmon streams. Bears determine a social hierarchy in these situations.
Many myths exist about bears. Contrary to popular misconceptions, brown bears can climb trees and can run downhill. Brown bears can sprint as fast as 35 mph. The notion that bears have poor eyesight is also untrue. Bears see and hear about as well as humans, although they depend most heavily on their outstanding sense of smell.
Bears are intelligent and curious animals. This sometimes gets them into trouble around Southeast Alaska communities, where they explore and exploit poorly secured trash as a food source. Towns surrounded by prime black or brown bear habitat (and lots of bears) have developed community-wide programs to keep wild bears from losing their natural aversion to people and becoming food conditioned problem bears.
Alaska is home to more than 98 percent of the U.S. population of brown bears. Grizzly bears and brown bears were formerly classified as different species, but both are now considered to be Ursus arctos. They are called brown bears in Southeast and Southcentral Alaska, and grizzlies in the Interior. Coastal bears, with seasonal access to abundant salmon, tend to be larger than Interior grizzlies because their diet is higher in protein.
Although most black bears in Southeast Alaska are black, they can also be cinnamon brown, dark brown or even white. Black bears have brown faces and most have a small white patch or mark on their chest. Glacier bears are black bears with an unusual coloration; a bluish-grey that ranges from a subtle tint to very distinct, light-colored coat.
What to look for: For a wildlife watcher on the water, the shoreline is the most common place to see bears. Bears beachcomb for dead animals and forage on shellfish in the intertidal zone. In April and early May, bears recently roused from hibernation will feed on sedges and other emerging vegetation along the shoreline. In late July, August and early September, they may be found near streams feeding on spawning salmon. Morning and evening are the best times to scan the shoreline. Look for a large, dark shape moving along the tideline or foraging in the beach grass.