There is no exact explanation, however, theories have abounded such as the bear stuck its head in some paint or has been shot with paintballs. However, the blue coloration is not splattered, nor does it have the lack of uniformity caused through paintball splatter. Others have suggested it is simply a hoax.
The coloration could be attributed to a genetic condition known as partial melanism, which is known to cause cobalt-blue coloration in mammals.
Melanism is a development of the dark-colored pigment melanin in the skin or its appendages and is the opposite of albinism. The word melanism is deduced from the Greek: μελανός, meaning "black pigment".