There are 8 kinds of bears (Ursus) in the world but I chose the North
American Black bear (Ursus americanus). I will be covering general information
about the bear such as their size, weight, color, food, etc., but I will
concentrate mainly on the hibernating cycle of the black bear. There are from
400,000 to 750,00 black bears in North America, and they weigh from 130 to 660
pounds with a body length of 50 to 75 inches. Their colors vary from black,
chocolate brown, cinnamon brown, pale blue (known as glacier bears) to white.
Black bears will often have a brown muzzle and may have a lighter color patch on
its chest. Its feet are equipped with strong, highly curved claws. They’re
omnivores; eating nuts, berries, fruits, insects (especially ants), deer and
moose fawns, carrion and in coastal areas on spawning salmon. Their habitat
includes forests with occasional open areas such as meadows. They occupy all of
Canada starting from the tree line going south. They live in all provinces and
territories except Prince Edward Island, where heavy de-forestation has happened
and preferably away from brown bears (larger competitors). The only main risk
for black bears are poachers who sell their parts illegally to the Asian
medicinal market. In northern areas of Canada, the bear undergoes a remarkable
metabolic transformation as it prepares for hibernation. Hibernation is an
energy-saving process bears have developed to let them survive for long periods
when there is insufficient food available to maintain their body mass. When they
stop eating and become increasingly lethargic, the bear will enter a cave; dig
out a den; or hole up in a dense brush pile, hollow log or tree cavity and
hibernate. Right before it does this it starts to gain weight so it can survive
the long months ahead. It can gain as much as 30 pounds per week. The bear
hibernates between four to seven months. When it’s in a hibernating state the
bear’s heart rate drops from between forty to seventy beats per minute to only
eight to twelve beats per minute. Its metabolism slows down by half, and its
body temperature reduces by 3 to 7 degrees Centigrade (5 to 9 degrees
Fahrenheit). Also its body doesn’t release any wastes like urea or solid fecal
waste but instead it’s recycled into usable proteins. During the hibernation
period adult males and adolescent bears lose between 15% and 30% of their weight
while a female cub with newborn loses as much as 40% of her weight. Most black
bears vacate their winter dens over a one to two month period starting in April
or May. Both the climatic conditions (snow cover and temperature) and
physiological factors such as the bear's age, the status of its health and its
remaining fat reserves affect the time it comes out. Normally, adult males
emerge first. Females with newborn cubs are usually the last ones to leave their
den, and continue with their life cycle.