Eastern Gray Squirrel With Paws To Mouth - Sciurus Carolinensis. The Eastern Gray Squirrel (Sciurus Carolinensis), Also Known As The Grey Squirrel Depending On Region, Is A Tree Squirrel In The Genus Sciurus. It Is Native To Eastern North America, Where It Is The Most Prodigious And Ecologically Essential Natural Forest Regenerator. Sciurus Carolinensis Is Native To The Eastern And Midwestern United States, And To The Southerly Portions Of The Central Provinces Of Canada. In The Mid-1800S The Population In The Midwestern United States Was Described As Being "Truly Astonishing", But Human Predation And Habitat Destruction Through Deforestation Resulted In Drastic Population Reductions, To The Point That The Animal Was Almost Absent From Illinois By 1900.