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The Black Bear's Fur


What purpose does the fur serve?
A bear's fur consists of two types of hair - the underfur and the outer guard hairs.  The underfur is soft and dense and serves primarily as an insulator.  The outer guard hairs are much thicker, longer and coarser.  While they also insulate, they serve to protect the body from foreign objects such as dirt, debris and insects.  They also repel water - when a bear emerges from a lake or creek, it will shake just like a dog, dispelling the water from its coat and leaving it practically dry. Finally, the outer guard hairs can be used to communicate.  Raised hackles indicate that the bear is angry or frightened.

Are all American black bears black?
The name is misleading
because not all American black bears have black fur.  This name was given to them by Europeans who saw only black-colored bears when they arrived in North America.  As settlers pushed westward, they began to encounter bears of different colors.  This led them to mistakenly believe they were seeing a different species.  It was discovered however that they were all the same species, just with different coat colors (known as phases).  American black bears can be:

black... brown... cinnamon...

 

blonde... ... and even white.

Why would black bears be different colors if they are all the same species?
While the causes are not perfectly clear, there is evidence to suggest that coat colors vary as a mechanism of camouflage or due to climate and habitat.  Bears in moister, more densely forested regions tend to be black, while bears in the West, where conditions are drier and vegetation is sparser, tend to be brown or cinnamon.  A black coat allows the bear to blend into the shadows created by dense trees and brush, and a brown coat blends better with the sandier, browner landscape.  In addition, black retains heat far more than does a lighter color, so brown phase bears are less susceptible to heat stress in more open terrain.  The surface temperatures of a black bear's fur can heat to 180 degrees Fahrenheit in the direct, hot, summer sun.  Finally, there is evidence to suggest that melanin, the pigment responsible for the black coat color, is more resistant to abrasion, thus it would be advantageous to those bears living in heavily forested regions.  Only 1% of the black bears in Pennsylvania are brown or red in color, while over 90% of the black bears in Yosemite National Park in California are tan, light brown or cinnamon. 

Are the Kermode bears of British Columbia albinos?
No, the "spirit bears" of British Columbia are not albinos but simply another color variation.  If they were albinos, they would lack color pigment in their eyes and skin as well as in their fur.  While exceedingly rare and primarily isolated to a few islands off the coast of British Columbia, these white bears are as normal and healthy as any black-colored black bear.  Their color arises from a mutation in a particular chromosome that is responsible for coat color.  The mutation did not prove lethal to the individual(s) who initially carried it, so it remained in the "genetic" population.  Since island populations are isolated, breeding occurs in a rather small circle of individuals, thus passing the gene more quickly than would otherwise occur.  This allowed the gene to become prevalent, and now one in every ten cubs born on these islands is white in color.  A black sow can give birth to a white cub, and visa versa.  In fact, cubs of a variety of colors can occur in the same litter. In 1997, a white bear was seen at the Vince Shute Wildlife Sanctuary. Although he was not a Kermode bear, his appearance was very similar to that of the "spirit bears." Click here to learn more about this amazing animal.

What is the rarest color phase of American black bears?
While white is the rarest color phase, a very uncommon and particularly beautiful color phase of the black bear is the blue-gray or glacier bears of southeastern Alaska, northwestern British Columbia and the southwest Yukon.  The undercoat of the glacier bears is a rich blue-black, while the outer guard hairs are long and white (or light yellow) with silver tips.  This color variation probably evolved during the last ice age when populations were isolated along the unfrozen sections of the coastline, due to the biological process of genetic drift (random fluctuations in the genetic composition of a small population).  The blue-gray color is ideal camouflage against the backdrop of frozen ice - the bears are nearly impossible to spot unless they are moving.  Unfortunately, this color phase is on the decline.  Immigration of non-glacier black bears and emigration of glacier bears across the now unfrozen landscape, are causing the gene frequency to be eliminated in the face of more dominant color phases, as the two mingle and mate. 

Why do some bears have different colored markings on their chest?
The markings on the chest, commonly called a chest blaze, can be a variety of shapes and sizes and are white or light brown in color.  Not all bears have chest blazes.  They can consist of a small dash, a deep V, or a "patch".  While there is no way to be certain, the current theory is that these chest blazes are used for communication and identification among the bears themselves.  80% of all cubs are born with chest blazes, but many lose them as they age.  If the mother has a blaze, the cub is more likely to retain theirs throughout its lifetime.  

 © Bill Noerenberg

Why does a bear's coat look different in the summer? 
Bears molt annually in the early summer.  They shed both their underfur and outer guard hairs, leaving only a short, sleek summer undercoat.  Each individual molts at a different rate and in different ways.  Some bears will molt from the face backwards, while others do so in a more helter-skelter, all-over pattern.  Their new coat is growing in as the old one is being shed, so that by fall they have their thick, luxurious coats once again.    

Do bears' coats change color?
Yes, a bear's coat can change color - from brown or cinnamon to black.  This generally happens in the juvenile or sub-adults years.  Changes seen in older bears are usually attributable to bleaching, where the tips of the hairs are lighter than the base. 

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