many years ago when I was a kid, my Dad brought home to baby squirrels. My mom bottle fed them , had them in a box with heating pad..when they finally got 'fur' , they were the cutest things, like little mini squirrels, very cat like, but very very mischievious! had to be watched 24/7 when out of their cage.
My Dad built a big cage for them, and we routinely let them out to do explore, climb trees, at nite, he'd give them a whistle and they'd come scampering back to their cage..Very friendly and easily handled , back then anyway