Around being the operative word, of course. Humans and chickens are outliers in that we get 2.21 billion and chicken gets 2.17 billiion beats. But a lot of other animals teeter the 1 billion line: horses, pigs, rabbits, elephants, cats, whales, etc. Animals big or small, fat or strong, fast or slow—it seems like there is a magic number for us all. Other than small dogs. They got the short end of the stick. More here.