In addition to having a role in mating displays and in fighting off competitors, the huge claw helps male fiddler crabs in staying cool, say scientists.
Dr Zachary Darnell and Assistant Professor Pablo Munguia tested a bunch of Gulf coast fiddler crabs (Uca Panacea) – both those who still had their major claws and those who had lost theirs.
In the experiment, researchers shone lamps on crabs with an intact major claw and on crabs that were missing theirs.
They measured the crabs' body temperature every 10 minutes and found that the crabs lacking the large claw took much longer to cool down.
Their study focusing on the Gulf coast fiddler crab (Uca Panacea) was recently published in the American Naturalist journal.
The major claw likely functions like a heat sink, with heat being transferred from the body to the claw and dissipated into the surrounding air through convective heat transfer.
Dr Zachary Darnell