Chela injuries in the fiddler crab,Uca burgersiholthuis

Abstract

Over 25 % of specimens of male Uca burgersi collected in Barbados showed signs of injury to their major chelae. Most of these injuries were small punctures found on the outer surface of the manus consistent with wounds inflicted during intraspecific combats, especially during heel and ridge contacts. The major chela contains muscle of an intermediate type (sarcomere lengths 4.4–6.8 μm) not different from that found in minor chela. There is no reason to suppose that either the muscle or the exoskeleton are reduced or lightened as might be supposed if the claw were simply a symbol. It is proposed that injurious fights are more significant in the life of the individual crab than has previously been suggested. This would be in accord with the recent theories relating to animal combat and ritualization.