He's trying to not make it obvious how baffled he is. Apparently, it doesn't matter how much he learns about Angel's home; there will always be something left to make him speechless. There are creatures who set themselves on fire in self-defence?

It takes him a few seconds to come to the conclusion that he always has to come to: It's just like that. Leave it.

"The predators do not have anything like that either," he finally says. "They have sharp teeth and claws, strong jaws and sometimes great numbers. That is all."