This reminds me that a while back I read a theory (
http://www.ornery.org/essays/warwatch/2005-06-19-1.html) that dogs and humans domesticated each other, and that "We remain deficient in the things dogs did for us; they continue to depend on us to provide them with food and protection.", and that "that dog brains and human brains underwent a shrinkage about ten thousand years ago, again at the same time."