Charles Darwin made numerous seminal contributions to the study of animal behavior over his long career. This essay places these contributions in the context of Darwin's life, showing his long-standing interest in psychological and behavioral issues encompassing all species, including humans. Ten areas are highlighted: natural history;…

Scholars interested in play in humans should take note of the growing literature on play in other species, especially in light of the application of evolutionary approaches to virtually all areas of psychology. Although most research on animal play deals with mammals--particularly rodents, carnivores, and primates--studies have recorded play of…