Black Squirrels.

Black squirrels, a subspecies of the Eastern Grey Squirrel, live all over northern United States and Canada. These squirrels exhibit very interesting behavior. They are known as a scatter-hoarder, in which they store hoards of food in various places for later recovery. Their excellent spatial memory and ability to remember landmarks allows them to do this. Interestingly, they will pretend to bury their food if they feel that something is watching them. 

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Another interesting characteristic of squirrels is their ability to climb down a tree head-first. They are one of few animals that can do this. Squirrels do this by turning their hind paws backwards so that their back paws are facing up the tree.

Squirrels often build nests, called "dreys," are crepuscular, meaning they are most active during early morning and late day hours, and do not hibernate. Predators include hawks, dogs, cats, raccoons, and snakes. 

Squirrels breed twice a year, with two to six young per litter. Also, the young are born naked with their eyes closed. Squirrels can live up to 20 years old, however, they normally live to about 12 or 13 in the wild. 

Communications involve both vocalizations and postures such as tail flicking. These communications are used in mating as well as to ward off predators. Interestingly, vocalizations and body language vary between different habitats. For example, squirrels living in a quiet habitat such as a forest will use vocalizations more. A population living in a noisy city will focus more on visual cues, as auditory cues may be hard to hear. 

References:

http://en.wikipedia.org/wiki/Eastern_Grey_Squirrel

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