The black squirrel is a subgroup of the eastern gray squirrel. Other than colour, black squirrels have the same size, behaviour and habitat as greys. They are common in the Midwestern United States, eastern Canada, and parts of the Northeastern United States and the United Kingdom. Individual black squirrels can exist wherever grey squirrels live. Grey mating pairs cannot produce black offspring. Gray squirrels have two copies of a normal pigment gene and black squirrels have either one or two copies of a mutant pigment gene. If a black squirrel has two copies of the mutant gene it will be jet black. If it has one copy of a mutant gene and one normal gene it will be brown-black. In areas with high concentrations of black squirrels, mixed litters are common. The black subgroup seems to have been predominant throughout North America prior to the arrival of Europeans in the 16th century, as its dark color helped them hide in old growth forests which tended to be very dense and shaded. As time passed, hunting and deforestation led to biological advantages for grey coloured individuals. Today, the black subgroup is particularly abundant in the northern part of the eastern gray squirrel's range. This is likely due to the significantly increased cold tolerance of black squirrels which lose less heat than greys. Black squirrels also enjoy concealment advantages in denser northern forests. The first wild black squirrel in the uk was spotted in 1912 outside Letchworth in Hertfordshire and has been spreading throughout the area since. The latest estimates show there could be as many as 25,000 in the east of England. Around Hitchin and Letchworth the black squirrels already outnumber greys and could be dominant throughout the eastern counties in the next 20 years. For more videos, photos and blog posts like this please visit http://www.wholesomeday.com Twitter: https://twitter.com/wholesomeday/ Tumblr: http://wholesomeday.tumblr.com/ Pinterest: http://www.pinterest.com/wholesomed/ Facebook: https://www.facebook.com/wholesomeday