INTRODUCTION

The giant panda is one of the national treasures of China. Many factors, related primarily to increased human activity, have caused a marked decline and geographic fragmentation of the wild population. To preserve this endangered species, the Chinese government, in partnership with many nongovernmental organisations (inside and outside China), has invested significant human and material resources to benefit in situ conservation. These collective efforts have resulted in the establishment of more than 40 nature reserves in southwest China in the provinces of Sichuan, Gansu and Shaanxi.

Giant pandas have been sporadically maintained in captivity since the Han Dynasty (206 BC to AD 226) (see Chapter 1). However, it was not until the 1940s that there was serious interest in exhibiting the species in China. It took more than 20 years of giant panda husbandry experience to produce the first cub in captivity, at the Beijing Zoo in 1963. Much progress has been made in the subsequent years in understanding basic giant panda biology and making it possible for the species to reproduce consistently in captivity. This chapter reviews the brief history and significance of ex situ breeding efforts for the giant panda.

THE SIGNIFICANCE OF EX SITU BREEDING PROGRAMMES FOR THE GIANT PANDA

The giant panda is particularly vulnerable to external pressures, in part because of an inherently slow rate of reproduction.

INTRODUCTION

Historically, the breeding of giant pandas in ex situ programmes has been difficult due to behavioural incompatibility and interanimal aggression. Because some individuals fail to mate naturally, the potential loss of valuable genes is a major concern to effective genetic management (see Chapter 21). Consistently successful artificial insemination (AI) would allow incorporating genetically valuable males with behavioural or physical anomalies into the gene pool. This strategy becomes even more powerful when used in the context of a genome resource bank (GRB), an organised repository of cryopreserved biomaterials (tissue, blood, DNA and sperm) (see Chapter 7). The use of sperm cryopreservation and AI allows the movement of genes among zoos and breeding centres without needing to transfer animals, which is both stressful and costly.

‘Assisted breeding’ refers to the tools and techniques associated with helping a pair of animals propagate, from AI to embryo transfer to cloning, among others (Howard, 1999; Pukazhenthi & Wildt, 2004). With the exception of AI, there is not much need for most other assisted-breeding techniques for the giant panda. As will be demonstrated here, AI is quite adequate for dealing with most cases of infertility or with helping to maintain adequate gene diversity in the captive population. In fact, the major breeding facilities, especially the China Conservation and Research Centre for the Giant Panda (hereafter referred to as the Wolong Breeding Centre) and the Chengdu Research Base of Giant Panda Breeding, routinely use AI to increase pregnancy success.

INTRODUCTION

The foundation of any managed breeding programme for animals living in captivity is a studbook. This is the chronological listing of animals in the historical captive population detailing birth and death dates, gender, parentage, locations, transfers and local identification numbers (Glatston, 1986). Analyses of these data provide critical information on past trends in population size, age-specific reproductive and survival rates, age structure, numbers of founders, degree of inbreeding, loss of genetic diversity and other measures useful for evaluating temporal changes in a captive population. This information then becomes the basis for making management recommendations to enhance the demographic and genetic security of the captive population (Ballou & Foose, 1996). Demographic security is needed to ensure that an adequate number of breeding-aged animals are available to reproduce at the rates needed to grow or maintain the population at its desired size. Genetic diversity is required for the population to remain healthy and to adapt to changing environments (i.e. experience natural selection).

The 2001 International Studbook for the Giant Panda contains detailed life history information on 542 giant pandas that have lived in zoos around the world (Xie & Gipps, 2001). The first entry, giant panda Studbook (SB) Number 1, is Su Lin, a wild-caught female who arrived at Brookfield Zoo on 2 February 1937 (see Chapter 1). A quick scan of the studbook leaves one with the impression that the captive population's dynamics are dominated by entry and subsequent death of wild-caught animals without sustainable reproduction.

INTRODUCTION

This book deals mostly with new biological knowledge and the use of that knowledge to benefit the giant panda by enhancing health, reproduction and management. It is an important strategy for modern-day zoo scientists, conducting ‘basic research’ to learn as much as possible about previously unstudied phenomena in any species, especially those that have received little, if any, attention.

In many ways, a scientist affiliated with a zoo is no different than a university research professor – both study mechanisms by using the scientific method to test hypotheses (Wildt, 2004). What is different about zoo science is the growing emphasis on results having practical uses – addressing issues that are relevant to allowing an animal to be better maintained in captivity, to allow it to thrive, reproduce and help sustain its species. In a perfect world that new knowledge will have duality of purpose, being useful to improving the conservation of in situ as well as ex situ populations. In fact, there now are many examples of ‘captive’ studies that have been useful for re-invigorating or re-establishing wild populations (e.g. golden lion tamarin, scimitar horned oryx, Florida panther, black-footed ferret, red wolf, California condor, among others). But having an in situ benefit is not an essential prerequisite to studying a species because the primary target is always the production of new knowledge – intellectual capital that improves our understanding of the wonders of biology and the natural world.

INTRODUCTION

While many recent advances have been made in the breeding of giant pandas ex situ, historically this species has never reproduced well in captivity. Sexual incompatibility, health problems, low fecundity and a juvenile mortality rate in excess of 70% have contributed to low reproductive success (O'Brien & Knight, 1987; O'Brien et al., 1994; Peng et al., 2001a, b). Wild- and captive-born giant pandas, particularly those captured at a young age, traditionally had difficulty producing offspring in captivity upon becoming adults (Lu & Kemf, 2001). As a result, the ex-situ giant panda population has not been self-sustaining and, until recently, its growth has relied on introducing animals captured from nature. In some cases, this included individuals that appeared ill (rescues) or cubs that were believed to be neglected or abandoned by their mothers. Later field studies, however, revealed that females often leave cubs alone for four to eight hours while foraging, and in one documented case for 52 hours (Lu et al., 1994). Recently, China has placed a general moratorium on capturing wild giant pandas for captive breeding (Lu & Kemf, 2001), a move that forces the breeding community to develop a self-sustaining population.

The goal, however, is not only ensuring demographic self-sustainability but also the maintenance of genetic diversity. The deleterious effects of inbreeding are well recognised (O'Brien, 1994a; Frankham, 1995; Hedrick & Kalinowski, 2001; Frankham et al., 2002).

INTRODUCTION

For more than five decades, various nonhuman primate species have been studied to determine how early rearing experiences influence behaviour in later life. Because of this wealth of information, the nonhuman primate literature is extremely useful for application to the giant panda in developing appropriate methodologies, testing hypotheses and understanding the breadth of behavioural outcomes that might result from different types of early socialisation. Although we recognise the limitations of comparing these distantly related taxa, we believe that the depth of controlled nonhuman primate studies makes comparisons worthwhile and of scholarly interest. Given the close phylogenetic relationship between the giant panda and other carnivores within the superfamily Canoidea (Ewer, 1973; O'Brien et al., 1985), other species within this group may also be useful comparative models, and these are also briefly reviewed.

Giant pandas in captivity can experience inadequate sexual behaviour, maternal behavioural deficits and severe aggression, which is also common to bears, other carnivores and nonhuman primates. It is our general hypothesis that socialisation (particularly the early relationship between mother and cub) is important in the ontogeny of normal social behaviour. Our long-term goal is to develop and evaluate management interventions that will overcome behavioural inadequacies and contribute to creating a naturally reproducing, self-sustaining and genetically viable population (Lindburg et al., 1997; Zheng et al., 1997; Zhang et al., 2000; see also Chapter 21).

Most captive giant pandas are housed, bred and raised in breeding centres and zoos in China.