Science doesn't have an answer about the origin of "Squirrel Girls" yet. Harbard and Camdridge have discovered interesting details ('10) in squirrel girls: About 65.7% are brunettes, 80.5% are charm, kind and lovely, 59.2% are females. Now I'll give you some examples:
Rachel Ray "Chef"
College Girl, at Cambridge indeed
Zack and Cody, they belong to the 40.8%
If you know a Squirrel Girl, or Guy, don't reject them, they are good people...