The Western Grey Squirrel, also known as the California Grey Squirrel, is a common sight throughout western North America. Although the species is known for its greyish-brown fur, there are a few synonyms that reference this little critter's unique characteristics. These might include the Baja Gray Squirrel, the Oregonian Gray Squirrel, or even the Sierra Gray Squirrel. Regardless of the name, however, the Western Grey Squirrel is an arboreal species that can be found in many different habitats, from urban parks and gardens to forests and woodlands. They have a varied diet, don't hibernate, and are not usually a threat to humans.