Causes of sexual dimorphism in performance traits: a comparative approach

Questions: Are there differences in whole-animal performance between the sexes, and what are the causes of this sexual dimorphism? Organisms: Humans, horses, greyhound dogs, pigeons, and lizards. Methods: We analysed performance records of human athletes, racehorses, greyhound dogs, racing pigeons, and lizards with respect to sexual dimorphism. Using the lizard data set, we correlated sexual dimorphism in running performance with sexual size dimorphism, reproductive effort, and territoriality. Results: The athletic abilities of male organisms are generally greater than those of females. The difference is much more pronounced in humans than in horses, greyhound dogs, and pigeons. Within lizards, males are generally faster than females, but do not differ consistently in endurance. Among lizard species, body size dimorphism, territoriality, and reproductive effort do not predict the degree of sexual dimorphism in performance.