When conditions are right, territorial crustaceans will go to bat for their rivals
Fiddler crabs will do battle to help a punier rival, a report in the May American Naturalist concludes. But it isn’t out of kindness.
Ecologists already knew that male fiddler crabs will sometimes take on an attacker who is trying to invade a neighbor’s territory. By setting up a series of bouts between crabs of the species Uca annulipes on a beach in Mozambique, Australian researchers have found that the crustaceans defend only smaller neighbors. And they do so only when an intruder is intermediate in size between their neighbor and themselves.
Size has a lot to do with which crab is going to win a fight. So the rules of crab engagement sugge