Second, you're just plain wrong about animals. There are animals that kill for pleasure. An entire species of animal we commonly refer to as the house cat kills just for fun. Other examples exist in nature, just not on a large scale, but then you really can't say that humans kill for pleasure on a large scale either. The Tsavo lions were belived to have been two such animals, but there are countless examples out there, this is why we kill any animal that kills a human.
Dolphins - those fun-loving cetaceans - are known to regularly engage in rape in the wild. The "problem" is something other than homo sapiens; the "problem" is sentience and/or sapience. Folks who place beasts above their fellow human beings baffle me to no end.
