You Want A Piece of This? (Please Please Please Don't Take a Piece of This!)

Nature lies. Organisms send signals to each other, and often those signals are honest--in other words, when another organism receives the signal, it can reliably use it to figure something out about the sender. Male fiddler crabs, like the one shown here, send a big, loud signal with their oversized claw. Often, that signal essentially says, "Do not mess with me." And in many cases, that's good advice. Sometimes, though, it's a major bluff. Male fiddler crabs dig burrows to which they try to attract females. The crabs mate, and the females stay in the burrows to lay their eggs. The good burrow-digging real estate is limited, and so many male fiddler crabs end up wandering around, in the hopes of throwing another male out of his burrow and taking it over. A male crab in a burrow will raise up his big claw from time to time to signal ...