Comprehensive Breeding Techniques for the Giant Panda.

The dramatic growth of the captive giant panda (Ailuropoda melanoleuca) population exemplifies how the application of scientific findings to animal care and reproductive management can improve conservation breeding outcomes. Detailed behavioral studies of giant panda estrus, pregnancy and cub rearing have demonstrated the importance of husbandry management that supports natural reproductive behavior to enhance breeding success. Natural breeding has been valuably augmented by the development of assisted reproductive techniques founded through detailed studies of the reproductive physiology of the giant panda and outlining fundamental information about reproductive seasonality, male fertility and characterization of the estrous cycle. The resultant holistic understanding of giant panda reproduction has improved reproductive success in the captive population to such an extent that it is now self-sustaining and provides surplus animals for reintroduction. Despite these significant advances, there are knowledge gaps and remaining challenges to be addressed. Pregnancy detection remains the single biggest challenge when determining if natural mating or assisted breeding have been successful. Because pregnancy can only be determined in the few weeks prior to parturition, there are gaps in understanding and detecting delayed implantation and early embryonic loss. Additionally, dynamic management practices and standard of care for reproductive assistance needs to be developed. Only large breeding centers in China have the ability to promote normal reproductive behaviors and allow mate choice for the giant panda. These challenges need to be addressed in the near future in order to maintain a self-sustaining, genetically diverse and behaviorally competent captive population. This chapter documents the development of successful giant panda managed breeding programs by focusing on three key areas, (1) the development of science-driven reproductive techniques to improve fecundity in a species where the mating system was poorly understood, (2) how targeted research and adaptive management of social settings surrounding estrus and breeding improved reproductive success, and (3) insights and solutions to challenges faced across the program's history with future directions for research.

Improving the sustainability of ex situ populations with mate choice.

Many breeding programs managed by the Association of Zoos and Aquariums' (AZA) Species Survival Plans® (SSPs) are not meeting goals for population size and genetic diversity due to failure of recommended pairs to breed successfully. According to AZA Population Management Center analyses, as many as 80% of recommended breeding pairs fail to produce young before the next breeding and transfer plan is issued. Determining reasons for failure and ensuring that a specific pairing produces offspring can be challenging. Mate incompatibility, one possible reason for failure, might be addressed by allowing mate choice. Although many SSP® coordinators and breeding managers, who implement breeding recommendations at their institutions, recognize the potential benefits of mate choice, examples and models for presenting and assessing choice are lacking. Here we review examples from birds, rodents, lagomorphs, marsupials, carnivores, fishes, and insects where mate choice has been incorporated. These examples provide strong evidence that free mate choice and mating with preferred partners increase a variety of reproductive success measurements when compared to assigned mate pairings. We suggest innovative housing and breeding arrangements for better incorporating mate choice into the management strategies for species held ex situ. Further, we discuss the fitness consequences and welfare implications of allowing choice. We advocate for a more systematic use of behavioral research in cooperative breeding programs. Behavioral management for mating can yield more successful programs, thus ensuring SSP® genetic and demographic goals are met, while simultaneously improving welfare.

Blood Lead Levels in Captive Giant Pandas.

Fifteen giant pandas (Ailuropoda melanoleuca) from the Chinese Conservation and Research Center for the Giant Panda (CCRCGP) in Bifengxia, Sichuan, China were analyzed for blood lead concentrations (Pb-B) during the 2017 breeding season. Thirteen of the 15 bears showed Pb-B below the method detection limit (MDL) of 3.3 µg/dL. The two remaining bears, although above the MDL, contained very low concentrations of lead of 3.9 and 4.5 µg/dL. All 15 giant pandas in this analysis had Pb-B concentrations that were within normal background concentrations for mammals in uncontaminated environments. For a threatened species, whose native country is plagued by reports of extremely high air pollution, our findings suggest that giant pandas at the CCRCGP are not absorbing lead at concentrations that would adversely affect their health.

Vocal behaviour predicts mating success in giant pandas.

Surprisingly little is known about how mammal vocal signals are used to achieve behavioural synchrony in the lead up to copulation. The ability to signal short-term fluctuations in arousal levels and behavioural intention is likely to be particularly important for synchronizing mating behaviour in asocial species, which must overcome their natural avoidance and aggressive tendencies to mate. Here, we examined vocal behaviour during breeding encounters in captive giant pandas (Ailuropoda melanoleuca) to gain a greater understanding of how close-range vocal signalling mediates reproduction in this asocial, and conservation-dependent species. Our results revealed that the occurrence of different giant panda vocalizations and acoustic variation within these calls is predictive of successful encounters leading to copulation, as opposed to unsuccessful encounters that do not. In addition, key differences were detected between vocalizations produced during and just prior to copulation. These findings illustrate that vocal exchanges are crucial for achieving behavioural synchrony and signalling intention to mate in giant pandas, and could also provide a valuable tool for breeding programmes, helping conservation managers to assess the likelihood of breeding introductions leading to copulation or potentially injurious failure.

Sound transmission in a bamboo forest and its implications for information transfer in giant panda (Ailuropoda melanoleuca) bleats.

Although mammal vocalisations signal attributes about the caller that are important in a range of contexts, relatively few studies have investigated the transmission of specific types of information encoded in mammal calls. In this study we broadcast and re-recorded giant panda bleats in a bamboo plantation, to assess the stability of individuality and sex differences in these calls over distance, and determine how the acoustic structure of giant panda bleats degrades in this species' typical environment. Our results indicate that vocal recognition of the caller's identity and sex is not likely to be possible when the distance between the vocaliser and receiver exceeds 20 m and 10 m, respectively. Further analysis revealed that the F0 contour of bleats was subject to high structural degradation as it propagated through the bamboo canopy, making the measurement of mean F0 and F0 modulation characteristics highly unreliable at distances exceeding 10 m. The most stable acoustic features of bleats in the bamboo forest environment (lowest % variation) were the upper formants and overall formant spacing. The analysis of amplitude attenuation revealed that the fifth and sixth formant are more prone to decay than the other frequency components of bleats, however, the fifth formant still remained the most prominent and persistent frequency component over distance. Paired with previous studies, these results show that giant panda bleats have the potential to signal the caller's identity at distances of up to 20 m and reliably transmit sex differences up to 10 m from the caller, and suggest that information encoded by F0 modulation in bleats could only be functionally relevant during close-range interactions in this species' natural environment.

Free mate choice enhances conservation breeding in the endangered giant panda.

Conservation breeding programmes have become an increasingly important tool to save endangered species, yet despite the allocation of significant resources, efforts to create self-sustaining populations have met with limited success. The iconic giant panda (Ailuropoda melanoleuca) embodies the struggles associated with ex situ species conservation. Here we show that behavioural mate preferences in giant pandas predict reproductive outcomes. Giant pandas paired with preferred partners have significantly higher copulation and birth rates. Reproductive rates increase further when both partners show mutual preference for one another. If managers were to incorporate mate preferences more fully into breeding management, the production of giant panda offspring for China's reintroduction programme might be greatly expedited. When extended to the increasing numbers of species dependent on ex situ conservation breeding to avoid extinction, our findings highlight that mate preference and other aspects of informed behavioural management could make the difference between success and failure of these programmes.