Chemical Signals in Giant Panda Urine (Ailuropoda melanoleuca)

Abstract

The Giant panda (Ailuropoda melanoleuca) is a conservation reliant endangered species and it is of increasing importance to establish a self-sustaining panda bear population in breeding stations and zoos. However, the major problem of captive breeding is missing motivation in male pandas and/or their inability to achieve intromission. In the wild, giant pandas are solitary but congregate to mate during the annual breeding season when a female goes into estrus, which lasts for 2 or 3 days only once a year. Chemical signals undoubtedly play a major role in panda reproduction for mate location, mate choice, and advertisement of reproductive condition. We used two techniques to analyze urinary compounds in a female and male giant panda, stir bar sorptive extraction (SBSE) and static headspace analyses (SHS). SBSE extraction confirmed the release of decanoic acid into the urine during the episode of seasonal estrogen secretion which is responsible for estrous behavior and ovulation. The appearance of decanoic acid 6–8 days prior to the day of peak receptivity in two females over two consecutive years might indicate a role of the substance in mate attraction. This finding closely agrees with observations that female pandas first start scent marking activities 6 days prior to the estrogen maximum. In addition we were able to demonstrate the presence of an unknown substance with a major ion at m/z 127. The substance shows a clear estrogen dependency, however, this finding is limited to one animal. Applying SHS revealed an additional unknown substance that peaked prior to or after peak receptivity. As with the aforementioned substance additional analyses are required to confirm this finding. If one of the substances examined in this study are of biological relevance they have the potential to be used as environmental enrichment to stimulate reproduction or naturalistic behavior of pandas in captivity.