This is really a question for PZ Meyers. Why did Tyrranosaurs have such dinky little front legs, so short they couldn't even use them to lift food to their mouths? It seems so dumb. I was considering it as I lay in bed last night and then I thought, aha, sexual selection! Their means of locomotion (rear legs) is such that they don't absolutely need front legs to get around. So maybe it was originally a signal, like, I'm so extrordinarily bad-ass that I can thrive even with these relatively wimpy arms! And then some kind of sexual selection feedback loop set in, and they were on a path to developing little nubbins and finally no arms at all, but they all got blown up by a meteor. The End. But then I thought, well, it can't really be the case that every time we see some apparent design flaw in a creature we're allowed to say about it, this is so stupid that only a really healthy, robust animal of this sort could survive, etc. You can't just claim sexual selection for everying, because chance ensures that lots of animals are just messed up from a teleological perspective. There's no guarantee that creatures will be optimally constructed; they just have to be good enough to stay alive and are saddled with all sorts of inherited templates which it is too late to change. So what do you guys think? Tell me what real scientists think so I can replace my imaginary version with a truer one.