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Black Bear Ursus Americanus Essay Research Paper

Black Bear (Ursus Americanus) Essay, Research Paper


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 maint

ain 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.


Bibliography


I


only used the web to find information and these are the sights I visited:


http://www.nature-net.com/bears/black.html http://www.bearden.org

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