The Eastern Gray Squirrel (Sciurus carolinensis)
… is perhaps North America’s most variable squirrel species. The color morph the species is named for is the traditional gray one (bottom center), which is found throughout their range. The black morph is also common, although it is absent from the very south of the squirrel’s range. In parts of the north however, black often outnumbers gray.
Some studies suggest the black coat presents a survival advantage in these cooler latitudes. Sprinkled in with these two are several other much rarer color morphs, often quite regional. At middle latitudes, the non-gray colors are often associated with urban centers, where lower predation threat means all morphs have a roughly equal chance of survival. Coat color is a genetically inherited trait, and a pairing of two morphs will sometimes result in mixed-coat litters.
The Gray Squirrel is native to eastern North America, but has been introduced to the west coast as well as a number of places overseas, such as the UK, where it has become an invasive pest…
[Photos - top, left to right: scarlatti2004, Hewlett, NY; Adventures of KM&G-Morris, Vancouver, BC; Manda (postmoderngirl), Austin, TX
bottom, left to right:D.Derbyshire, eastern ON; Craig Elliot (Tjflex2), Richmond, BC; Robert Taylor (Bobolink), Stirling, ON; All but D.Derbyshire on Flickr]
(via: Peterson Field Guides)