There are many unanswered questions concerning the evolution and ecology of aggressive behavior in animals. It is, for example, unclear why the members of one species may be typically highly aggressive while those of a closely related species are relatively passive. Similarly, within a species or even among littermates, some individuals are frequently much more aggressive than others. These experiments will explore the causes, development, and function of species and individual differences in what is perhaps the most critical (and unstudied) aspect of animal aggression--defensive attacks directed by animals at predators. The experiments will be conducted using several species of newborn garter snakes. These animals are excellent for the investigation of defensive strategies in animals. They have large litters and newborns can be tested from the day of birth which allows for the study of the influence of heredity on behavior. They are also, like many newborn animals, preyed upon by a wide variety of predators from the moment they are born. In this project, the development of antipredator behaviors, particularly defensive attacks, will be studied in several species which are known to differ in characteristic levels of aggressiveness. In addition, the stimuli which cause inexperienced newborn animals to attack will be explored. Finally, the function of species and individual differences in defensive tactics will be assessed. In summary, this research will shed light on the significance of individual differences in behavior and on the factors that generate such differences.
