When you notice a characteristic of an animal and ask what its Darwinian survival value is, you may be asking the wrong question. It could be that the characteristic you have picked out is not the one that matters. It may have _come along for the ride_, dragged along in evolution by some other characteristic to which it is pleiotropically linked.
I wish the evolutionary psychology folks would paste this sentence to their wall.
I wish the evolutionary psychology folks would paste this sentence to their wall.