You hit on a topic that I've often thought about. Take cats, for example. They typically don't meow at other cats, only people. And they have certain other behaviors that they only use when interacting with humans, along with big eyes and round faces, baby-like traits that we can't resist as a people. Now, cats are very interesting because they are the only domestic animal that is almost entirely naturally selected (something like <5% of cats are bred intentionally). So, this begs the question: Have cats evolved "cuteness". They really serve no purpose other than companionship, and unlike dogs, whom we have bred to contain the traits we desire, they come by their desirability honestly. Can their cuteness be considered as part of their survival mechanism, a ploy to get gullible humans to feed and house them? My suspicion is yes.