Black Bears - Adaptations For Survival
To survive the harsh northern winters, black bears have many adaptations. The bear grows two different layers of fur. The under layer of fur is shorter and fuzzier and is there to insulate during the colder seasons. The outer layer of fur or "guard hairs" are glossy black and grow much longer than the inner layer. This system allows warmed air to be trapped in between and prevents heat loss. The bear's winter coats are shed in the spring.
During the late summer and early autumn black bears gorge themselves on food. They do this to gain an extra layer of fat to help in insulating and so that their bodies will have nutrients during the winter. As the weather gets colder, the black bear will begin to prepare a shelter for the winter. The shelter can be a cave, a hollowed out tree or any other similar space. The bear will line the bottom of it's den with grasses and leaves to lie on while it sleeps. Leaves and other vegetation is raked from several yards around the den to provide both insulation, and a comfortable bed for the winter.
As far as the true definition of hibernation goes, black bears do not hibernate. During hibernation, the body temperature drops and the metabolism slows. In the winter bears will go to sleep and their heart rates will slow. Their breathing rate will also drop to 5 or 6 breaths per minute. In this state, bears can sleep for extended periods of time and are capable of remaining in the same position for up to one month, but will awaken easily if disturbed. If the bear has not consumed enough food to last the winter, if it is an unusually warm day or if it finds it's den uncomfortable, the bear will get up to eat or find another shelter.
On common misconception about "hibernating" bears is that they do not excrete bodily waste during the time that they are sleeping. Some people believe that the bear will consume indigestible foods before denning up to create a fecal plug. This is not true and even though they do not eat, they live off of stored fat and do excrete some bodily wastes.
During the winter, black bears shed their foot pads and grow new ones. This was not known by researchers until recently, but some of the native tribes appear to have had past knowledge about this. Scientists are not sure why bears do this, but it is probably the reason that they seem reluctant to venture far from their dens. Their new foot pads are still too tender for long journeys.
Because they live in dense forests, black bears are sometimes thought to have relatively poor eyesight.However, their sense of smell and hearing seem to bevery sharp. To become aware of whatever dangers are around, bears will stand up on their hind legs and sniff the air. This allows them to both see and smell predators well before they meet face to face and helps them to find food as well.
Cubs are very frisky and are sometimes hard for the mother to control, but they are born knowing that when their mother gives them a warning growl, it is time to be quiet. Coyotes and adult male bears are real threats to a baby bear and some studies have reported that as many as 40% of new cubs are killed by adult boars. When the mother growls, the cub will scamper up a tree and out onto the thinnest branch that will support it's weight. There it will remain until it is told to come down by it's mother. In the tree, the cub will be safe because the thin branch is not enough to support the weight of any larger predator.
In the summer, bears roam in a very definite pattern searching for food. The bears will mark these territories by urinating, defecating and by biting and clawing at trees. These claw marks are a good indicator to other bears about the bear who made them because they reach up as up as high as they can to make these claw and bite marks.
The following photo shows a bear marking, made by scratching a balsam fir, in northern Ontario.
Some male bears have ranges up to 150 square miles from their home territory and females up to 50 square miles. On bear in Pennsylvania was tracked in an area ranging to 380 square miles. In either case, if there is an abundance of food, they won't roam as far.
When bears fear a conflict they will lower their heads, extend their lips, chop their teeth and emit a low moan. This is usually a warning to the challenger. They will also 'blow' pursing their lips, and expelling air, or 'woof' and snort. Bears are not usually aggressive animals and they will only attack if they feel threatened or are injured. However, Black Bears do threaten, and sometimes charge towards another bear, or person to protect a food source. A mother bear can become fierce with the birth of her cubs and may attack if she feels that their safety is being threatened. One study in the Great Smoky Mountains National Park recorded 624 aggressive acts toward humans, but only 6% (37) actually ended in contact.
Black Bears - Human Uses
In Ontario, the most important use that we have for bears is that they help to support our economy. Local and professional outfitters offer hunting packages for these animals and many people will come from other countries to hunt them. 80% of all black bears killed in 1989 were killed by non-residents. Bringing tourists into our country helps to generate money. If the hunter stays in our hotels or spends any money on entertainment while he or she is here, that is money made for Canada. People who are here to hunt have to eat and will spend money doing that. All of these things do not include the money that the hunter is paying the outfitter for the hunt and the $125 non-resident liscencing fee and a $30 export fee to take the hides and meat out of the province. In 1989, resident hunters spent $4 million in travel, new equipment etc. and non-resident hunters spent $10 million during their stays here.
At one time the bears' hides were used for rugs and robes for sleighs, but now about the only use people have for their glossy black coats are for trophy mounts and rugs and for the Queen's Guards Regiments tall fur hats.
Black Bears - How Black Bears Can Harm Humans
Black bears are considered a nuisance when they forage around garbage dumps and campsites. They enter into our parks and communities because they have learned that these places are an easy source of food. Bears also have the reputation of raiding farms and eating their crops, especially corn and oats. Bears begging for food in tourist parks have lost all fears of humans and this is when they can become dangerous. In the wild, bears are afraid of men and will usually retreat without confrontation, but nuisance bears do not fear humans, and sometimes, will not retreat. Unless the person has a rifle, the bear will likely win any contacts. Other than in these situations, or when the bear is injured or protecting cubs, the incidences of bears attacking humans have been fairly low.
Black bears can damage trees in the forest by clawing and biting to mark their territory. One study found that in a certain area, 30% of the trees had been damaged by the black bear.
Black Bears - Human Abuses
In the early 1900's many bears became part of traveling circus acts because they were easy to tame and could be taught to do tricks. However, in many cases these animals were mistreated and not given proper care. Now there are regulations governing their care to ensure against abuse, but even some zoos have standards that do not meet regulations for the proper and healthy treatment of these animals.
As with any other animal in the wild, the strain that we are placing on the environment has a direct impact on the bear. Polluting of the air and water by our huge factories and manufacturing plants destroys the animals home, food and can affect it's health. Deforestation cuts down many trees and reduces the areas that these animals can inhabit. Even when the trees are replanted, it will take at least 50 years for the forest to return to normal. Fires caused by careless campers also destroy acres of a bears territory and many animals can be killed in an out of control blaze.
In 1958 word was sent from London that the Queen's Guards were in need of bear hides for their hats. Leo DelVillano, mayor, encouraged the people of Timmins to help out and over 200 bears were killed. This is the type of thing that can go too far and wipe out an entire population in an area. It took almost 20 years for the local population size to recover.
Overhunting and poaching is another serious threat to the bear population. Although the black bear is not yet in danger of becoming extinct, many of the other species of bears around the world are. Studies done by Ontario naturalists have determined the amount of bears that can be harvested in different population sizes and other measures are being taken to ensure that the black bear does not become in danger of extinction.
Black Bears - Related Animals
Brown Bear - Ursus arctos
Distribution - Asia to Iran, Europe to Spain, North America to New Mexico
Coloration - blue-black, red, chocolate, tan, cinnamon or brown
Weight - the weights of different sub-species of brown bears vary greatly
the lightest sub-species (Syrian brown bear) weighs 400 lbs
the heaviest sub-species (Alaskan Kodiak) weighs 1800 lbs
the other sub-species of brown bears' weights lie between the Syrian and the Alaskan Kodiak
Physical Traits - stout and chunky, with a large hump of fat and muscle over the shoulders
2 inch long claws on forefeet used for digging
massive, wide head
Some Sub-Species - Siberian brown bear -Ursus arctos beringianus Himalayan red bear -Ursus arctos isabellinus
Manchurian brown bear -Ursus arctos manchuricus
the horse bear of Tibet and Western China -Ursus arctos horribilis
Alaskan Kodiak -Ursus arctos middendorffi