Fiddler Crabs: World's Pickiest Mates

Just like humans, female fiddler crabs check out the size of a potential mate’s pad before deciding if he’s marriage material.

And just like people, female bats often find their moms’ new boyfriends irresistible. Even though it’s open season on step dads, these bats won’t engage in incest. Like most girls, they just find Dad gross.