Back in my undergraduate days at Haverford College, a small liberal arts institution founded by Quakers a few miles west of Philadelphia, there was an earnest debate about whether our athletic teams should have an official mascot, and if so, what it should be. The "Fighting Quakers" moniker clearly didn't apply, though there was a faction that favored going with "Earth Quaker." Another favorite was the "Koala Bobs", in reference to a popular, home-drawn cartoon character in the college newspaper (Koala Bob had a sister Bernice at Bryn Mawr with punked out hair and suitably militant feminist sensibilities, and his best friend was a Kiki named Floyd). Since Quakers make every decision by consensus, we ended up without an official mascot and stuck with the default choice of "'Fords."
However, in the intervening years a new unofficial mascot has firmly taken root. The Black Squirrels, once a reference to non-Quaker Haverfordians and the predominant furbearer on campus in the compact size category, are now the unofficial mascot of my Alma Mater and can be purchased as plush toys in the campus bookstore - a sure sign that they have hit the big time.
Black squirrels are the melanistic form of the eastern gray squirrel, and once predominated throughout their range in the first grown forests where their dark coloration gave them a survival advantage. They persisted in the Midwest and in Canada when they all but disappeared from the Northeast, but are making considerable inroads from Washington, D.C. where they were introduced and elsewhere. Some gray squirrel litters still produce kits with the mechanistic mutation, and outside my window here in Northwestern CT I see one now, rooting for acorns.
Black Squirrels will sometimes drive off their gray cousins, and their dark coloration helps them retain heat in cold weather. As the eastern states reforest they may become more common here, though is the warming trend continues they may find it more advantageous to shift their core range southward.
There is no getting around the fact that black squirrels look much cooler than their grizzled gray relatives. A much better choice of mascot than a pigeon, or a starling whatever other fauna inhabits the Philadelphia suburbs.