A Free Choice Task Evaluating Chimpanzees’ Preference for Photographic Images of Sex Swellings: Effects of Color, Size, and Symmetry

摘要: Exaggerated sex swellings characterized by increased size of skin surrounding the anogenital region occur in female chimpanzees response to ovarian hormone fluctuations and are associated with likelihood ovulation receptivity. The generate heightened sexual interest from males evoke male competitive behavior. To determine potential attractiveness specific visual characteristics these signals males, a free choice task using push-button methodology that allowed subjects choose one stimulus pair pressing button corresponding was developed. Initially, preferences for food items were first determined based on animals’ selection actual items, followed same photographs subsequently preferred utilizing responses photographs. We found when between swellings, novel objects, other body parts, images both parts over showed significant preference parts. However, no swelling color or symmetry. Only subject displayed normal sized rather than enlarged swellings. Overall results suggest considered individually, alone not sufficient provoke responding.