5,416 species is a LOT. Even if only 20, or 10, of these species have 'curiosity', that's still a very different thing from ONLY humans having curiosity.

I personally see little difference in kind between that and the similar actions seen in baby humans. The fact that a human is far better able to direct their curiosity, I think is based on our different quantity, or capacity for intelligent curiosity.

Precisely what I thought. A dog's curiosity doesn't get it as far as a human's does, since a dog has much less capacity for symbolic thought (but probably still some capacity) and no way to record its thoughts or share the thoughts of other dogs.