The cost of aggression in an animal without weapons

Abstract To understand the prevalence and conditional use of aggression among animals, one has to know its costs and benefits. The obvious cost of aggression in animals that possess teeth, claws or other specialized weaponry is injury. Many species, however, do not have such body parts and thus cannot readily injure others. The cost of aggression in these animals is not well studied. We tested whether aggression has a fitness cost in fruit …