Everyone has pretty much summed up the intelligence question, but I totally know what you're saying about boas eyes locking onto you where balls just kind of stare into the distance. I'm pretty sure that boas have better eyesight, though. Balls rely on heat a great deal, and boas rely on eyesight a bit more than balls. So, probably, your boa can actually see that you're something, where the ball doesn't realize that you're not just part of the background...although I haven't actually asked them, so I could be wrong!
