The effects of sex, reproductive condition and context on discrimination of conspecific odours by giant pandas.

To elucidate some of the functions of chemical communication in giant pandas, Ailuropoda melanoleuca, we systematically exposed captive males, oestrous and nonoestrous females to each others' odours by providing access to one another's temporarily unoccupied enclosures. In comparison with control observations, pandas from all reproductive categories displayed a dramatic increase in several measures of chemosensory responsiveness, both when visiting another panda's enclosure and when encountering scent deposited in their home enclosure. Evidence for discrimination between odours encountered as a resident versus a visitor was minimal, but male pandas' response patterns were suggestive of a territorial function. We also found evidence for discrimination of sex and reproductive condition via chemical cues. Males showed a marked preference for female odours, investigating, licking, scent marking and vocalizing more in response to female than male odours. Males also vocalized more in response to oestrous than nonoestrous female odours. Nonoestrous females licked more and oestrous females vocalized more when encountering male than female odours. Our data on vocalizations suggest a potential role for odours in the activation of sexual motivation. We argue that the low reproductive success observed in captivity may be attributed in part to failure to provide sufficient opportunities for chemical communication, and encourage the judicious management of social odours to promote natural mating (e.g. using intersexual odour exposure to increase libido and decrease aggressiveness prior to mating introductions). Copyright 2000 The Association for the Study of Animal Behaviour.