This is blowing my mind. All this time I thought those sine curves with fur were just native Northeastern US creatures. It never even dawned on me that they wouldn't be native to cities. I once drove from Boston to Columbia, South Carolina. I got out at my friend's house and saw an anole on his porch. It acted just like a squirrel, even though it was a reptile.
If anyone has ever been to the University of Illinois then you would know that the squirrels are very friendly to all humans. This is because there was a shortage of squirrels on campus and in order to counteract this the President of the university started a program to breed more squirrels on campus which would also be friendly. The squirrels were taken from the city and selected amongst squirrels who already showed comfort around humans. I never realized that this happened elsewhere. Source: http://archives.library.illinois.edu/blog/squirrels/
Never really thought about it, but it seems kinda "duh" now. Why else would the arboretum in Golden Gate park, surrounded by city on three sides and ocean on one, be loaded with squirrels? They don't just fly in on their yearly migration. It's funny that the article mentions that seeing a squirrel in the city was once a sure sign that it was a pet. Nobody thinks of squirrels as pets now. My uncle did have a pet squirrel for a bit in the mid 90s though: Ricky. He rescued him from falling out of a tree and raised him in his house. There would be a squirrel running around the kitchen. Eventually he gradually re-entered the wild: he would go out in the backyard and spend more and more time in the trees and less time in the house. Seemed to work out pretty well.
Squirrels are wonderful animals, seeing them is always a welcome sight regardless of where it is. That's a great story about your Uncle! I've been curious about the prospect of a pet squirrel for the past year or two now as a temporary endeavor.