Dude! I remember reading about that! Very cool stuff. If I recall, the foxes were subjected to breeding criteria based primarily on freindliness and compatibility with humans. After numerous generations (and the study is still ongoing to my knowledge) the foxes have started to take on more of the PHYSICAL characteristics of domesticated dogs than they previously displayed. Not sure how much this proves, and the study isn't "finished" yet by any means, but it's certainly grounds to do other experiments with other species and see what happens.