As one of the world's foremost primatologists, Jane Goodall has become synonymous with the study of chimpanzees. Her book, In the Shadow of Man, describes her observations of a group of chimps in the Gombe Stream Reserve of Tanzania. Her research has made remarkable discoveries, uncovering the once unknown lives of wild chimpanzees. Her detailed book describes many social behaviors that are displayed by chimps, however, I will be focusing on the male chimpanzee's exhibition of altruistic behavior in terms of hunting, and its relation to increased fitness and sexual reproduction.
The evolutionary principle of all living organisms is to survive and reproduce. However, in place of the natural selection model, which portrays an image of passive and docile individuals being acted upon by the environment, altruistic behavior concentrates on the interactions among individuals and portrays organisms as selfish and calculating actors who seek to maximize their reproductive success. In these efforts, individuals must adopt strategies with different relative outcomes under particular circumstances. Altruism is key to the concepts of natural selection and survival of the fittest. Fitness is a measurement of an individual's genotypic contribution to subsequent generations and is often measured in the produced number of offspring (Boyd & Silk, 2003). .
Altruism can be traced throughout the evolution of many species, especially primates. The two basic types of altruistic behavior are dependent upon the relationship of the involved individuals. Kin selected altruism, which was first described by William D. Hamilton, is favored by selection if animals interact selectively with their genetic relatives. On the other hand, Robert Trivers states that non-relatives who have entered into a pact to exchange favors are taking part in reciprocal altruism (Boyd & Silk, 2003). Altruism within a family helps to ensure the advancement of genes and therefore, even if the individual is not necessarily "successful," the family will be, due to the number of offspring they produce as a result of the altruistic behavior.