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Studying Giant Pandas to Save Giant Pandas: A Special Report to FONZ Members

In conjunction with the loan of giant pandas Tian Tian and Mei Xiang from China, National Zoo scientists have developed a comprehensive ten-year research and training plan related to giant pandas. The research is designed to help ensure that pandas survive in zoos and in the wild. The following is a summary of the plan.

It seems the whole world wants a glimpse of the Smithsonian National Zoo’s new giant pandas. There is no doubt that Tian Tian and Mei Xiang are enchanting. Both possess the charm and charisma required to fill the job of ambassador for giant pandas in the wild. Blithely unaware of their mission as they cavort in their National Zoo habitat, these beautiful animals are helping us to inspire people with a desire to save giant pandas—and wildlife and wildlands everywhere. But they have another mission as well—and most people who come to visit them are as unaware of it as the pandas are. They are also helping us to learn how to save giant pandas. Think of Tian Tian and Mei Xiang as research collaborators.

National Zoo scientists have been studying giant pandas since the first pair—Ling-Ling and Hsing-Hsing—came to the National Zoo in 1972. Yet there remains much to learn. In some research areas, it is important to repeat the observations made on Ling and Hsing. By increasing the sample size, scientists will be able to tell, for instance, whether a behavior pattern is common to giant pandas or peculiar to individuals. In other areas, such as reproductive biology, the advanced techniques scientists are using today largely didn’t exist while Ling and Hsing were alive. What’s more, the opportunities for research and conservation initiatives in the wild, including the potential for bolstering the wild giant panda population in China through reintroduction, are greater today than at any time in the past.

This points to another role that Tian Tian and Mei Xiang play: that of fundraisers. The National Zoo’s ambitious ten-year research plan—a plan that we hope culminates in a growing, thriving population of giant pandas—will be costly to carry out. So will China’s official National Plan for the Conservation of Giant Pandas and Their Habitats. The magnetism of our pair has attracted, and will continue to attract, support from donors large and small. This will make saving giant pandas and their habitat possible.

Finally, there now exists a critical mass of collaborators in all areas of giant panda conservation and research: colleagues in China, including at the China Wildlife Conservation Association; China Research and Conservation Center for the Giant Panda, Wolong Nature Reserve; the Chinese Association of Zoological Gardens; the Chinese Academy of Sciences; Beijing University; Beijing Zoo; Chengdu Zoo; and the Chengdu Research and Breeding Base; at the San Diego Zoo and Zoo Atlanta, which also exhibit giant pandas; and at organizations like the U.S. Fish & Wildlife Service, World Wildlife Fund, and the Conservation Breeding Specialist Group of the World Conservation Union.

Growing Zoo Pandas

Today’s best estimate of giant panda numbers in the wild is about 1,100 individuals living in up to 32 separate populations mostly in China’s Sichuan Province, but also in Shaanxi and Gansu provinces. Some of these populations number in the hundreds of animals, others include just a handful. In addition, the world zoo population is less than about 150 individuals, most of which are in China (we use the word zoo here as shorthand to include traditional zoos as well as breeding centers and similar facilities). The zoo giant panda population represents a potential pool of animals for reintroduction. One strategy for saving the remaining total population of giant pandas (zoo and wild) is to view them as one "meta-population" and then develop strategies to link and expand this population. If panda populations cannot be linked geographically through creation of habitat corridors, meta-population management would include linking them through our interventions. For instance, we could move animals among the various populations or inseminate females in one population with semen from males in another, or both.

Despite some successes, giant pandas generally have not bred well in zoos. Thus, a major portion of the National Zoo’s research efforts in the next few years will be devoted to evaluating the reproductive competence of giant pandas in zoos as well as in the wild. Techniques to do this must also be developed.

One such technique involves monitoring endocrine, or hormone, function. In particular, measuring gonadal (reproductive) and adrenal (stress) hormone levels reveals much about an animal’s reproductive condition and its general well-being. For instance, patterns of change in the levels of various gonadal hormones may indicate the onset of puberty, normal estrous cycling, and pregnancy. Changes in adrenal hormone levels may indicate how much stress an animal is experiencing as a result of, for instance, contact with people or other disturbances in its habitat. Further, adrenal hormones and gonadal hormones may interact so that, for example, stress may alter secretion of gonadal hormones and thus negatively affect reproduction.

Traditionally, patterns of hormone secretion have been measured in urine samples, just as human pregnancy tests involve testing for certain hormones in a woman’s urine. National Zoo scientists will be developing the ability to measure hormones in the feces of giant pandas as well. Although National Zoo scientists have been collecting giant panda urine samples for many years, feces are more easily collected (biologists are notoriously unsqueamish) from zoo and wild animals than urine.

National Zoo scientists will use previously developed methods of monitoring hormones in urine and new methods of fecal hormone monitoring to study lifelong changes in endocrine function in Tian Tian and Mei Xiang. Monitoring hormonal changes will help scientists to better understand the reproductive biology of giant pandas. It will also help them determine how reproductive performance and animal well-being are influenced by the social system; by restraint, anesthesia, and translocation practices; and by pre-release conditioning and reintroduction. The impact of human disturbance or other environmental perturbations on animal well-being can also be assessed.

Another study designed to enhance zoo reproduction will focus on the relationships between reproductive success and each of the following: behavioral traits and temperament of individual giant pandas, husbandry practices such as enclosure size and diet, and physiological stress. National Zoo scientists will use data on these variables from giant pandas in several breeding facilities in China as well as from our own pandas and those at other non-Chinese zoos. Based on the results, they will suggest interventions that might improve giant panda breeding. For example, National Zoo scientists hypothesize that a diet of mostly bamboo, rather than concentrated foods, enhances reproductive success. If this prediction is supported by the data, then diet changes will be recommended at those facilities that feed their pandas concentrated foods. Follow-up studies will then test whether the diet change or other intervention does in fact make a difference to breeding performance.

Even when natural breeding success improves in zoo giant pandas, there will be a need for assisted reproduction, such as artificial insemination, to ensure that all possible males, even those unwilling to breed naturally, contribute genes to the next generation. (Only a few zoo males have ever fathered young through natural mating.) Moreover, preserving sperm, eggs, and other tissue in what some call a "frozen zoo" (and scientists call "a genome resource bank") will provide an insurance policy against a catastrophic decline in giant panda numbers. But there is an urgent need to learn much more about the details of gamete (sperm) physiology, as most work has been done on females. Thus, National Zoo scientists plan to focus initially on whether inbreeding or other factors affects sperm quality. Further, our scientists plan to collaborate with Chinese colleagues to test and improve techniques for freezing and thawing giant panda sperm. This will increase the success of artificial insemination and allow us to be confident that stored frozen sperm will maintain its viability over the long term. National Zoo scientists also plan to work with Chinese colleagues and funding agencies to develop an organized strategy for genome resources banking and to build one or two repositories in China.

Overcoming the problems giant pandas have mating successfully in zoos is an important first step. However, zoo pandas also seem to suffer from high levels of infant mortality. For instance, all five cubs born at the National Zoo died of bacterial infections within a few days of birth. National Zoo scientists also discovered that cubs in zoos in Madrid, Mexico City, and China similarly died of bacterial infection. This tells pathologists that the cubs aren’t receiving sufficient antibodies from their mothers to fight off infections caused by bacteria encountered during birth. As in many other species, newborn pandas receive maternal antibodies in colostrum, the milk a mother briefly secretes after parturition. The time during which the infant can absorb these antibodies is related to how long they persist in the mother’s milk. So, if the baby fails to nurse promptly, or the mother fails to offer proper and prompt maternal care, the baby loses the immunity the mother’s antibodies would have provided.

In domestic animals, such as horses, scientists have been able to extract antibodies from adults and prepare them to be given to foals either by injection or orally. National Zoo scientists plan to replicate this technology for use in giant pandas. This will increase infant survival, especially of babies that are rejected by their mothers (a common occurrence when twins are born) and must be hand-reared.

Another problem that arises in young zoo panda infants, especially those separated early from their mothers for hand-rearing or for other reasons, is stunted growth that may lead to disease or death. Studying giant panda lactation and milk composition, an area in which National Zoo scientists are leaders, will help to formulate appropriate diets for hand-reared pandas, thus enhancing their survival rates and increasing the zoo population.

Beyond Zoos

Increasing the number of giant pandas in zoos to create a self-sustaining population will offer an insurance policy against the species’ extinction in the wild. But the overarching goal is to ensure that the policy never has to pay out. One strategy to save giant pandas in the wild is reintroduction, although this will require achieving other interim goals, including the growth of the zoo population described above. Several aspects of the National Zoo’s research plan address the other requirements for eventual reintroduction, should that become necessary.

National Zoo scientists are steadily gaining experience in reintroducing zoo animals to natural habitats, most prominently through the successful golden lion tamarin reintroduction program that the National Zoo has conducted since 1984. In some species, such as black-footed ferrets, the way animals are released influences the survival rates of the introduced animals. Slow, careful preparation and training before release, and food and shelter support for some time after release—dubbed a "soft release" —may result in greater survival than a "hard release," which is the equivalent of going cold turkey. Tian Tian’s and Mei Xiang’s presence at the National Zoo will allow our scientists to determine what preparation, training, and support giant pandas might need to minimize mortality after reintroduction.

For instance, we will need to know about giant panda preferences for eating various species of bamboo. If we learn that giant pandas prefer to eat the bamboo species they were first exposed to in zoos, we will have to be sure to include in their zoo diet the species they are most likely to find in the reintroduction site. Similarly, we will test whether giant pandas instinctively recognize and avoid predators, such as leopards; if they do not, we can devise ways to train them to do so. While there is no reason to reintroduce giant pandas at this time, all of this research will set the stage for a reintroduction program if needed in the future and will offer insight to our Chinese colleagues as they decide whether, when, and where to reintroduce giant pandas in the wild.

Another set of wide-ranging studies will examine the environmental and social preferences of our giant pandas as they mature. For instance, we will examine whether our pandas prefer to be indoors or outdoors at various times of the day and year; what kind of trees pandas prefer to climb in (and what kind of trees can survive the wear and tear); and the influence of visitors on the animals’ behavior. This and other information will ensure that our giant pandas live in the best possible zoo environment. At the same time, extensive observation of our giant pandas will let us document the development of their social and reproductive behavior, such as scent-marking, play, vocalizations, and courtship, and compare their development to that of Ling-Ling and Hsing-Hsing.

Part of creating the best possible circumstances for Tian Tian and Mei Xiang will be offering them preventive veterinary medical care, such as regular health exams, immunizations against disease, infectious disease screening, and imaging of internal organs. Such treatment offers two additional benefits. First, we can establish "normal" values for various medical aspects of giant pandas, addressing the problem of not knowing whether, for example, what we see in an ultrasound image of a kidney indicates health or disease. Amazingly, only one text book reports the normal anatomy of giant pandas, and this is based on a single necropsy (the animal equivalent of an autopsy). Our comprehensive veterinary medicine program will thus significantly advance understanding of how to care for giant pandas.

A key component of health is adequate nutrition, and for giant pandas that means getting all they need from bamboo. But does bamboo contain all the nutrients, in the proper amounts, that a panda needs for health, growth, and reproduction? Our scientists plan to answer this question by determining the nutritional composition of various species of bamboo and, further, how this might differ seasonally, in different locations, and among the parts of the bamboo (such as shoots, new leaves, and old leaves). Of particular interest is selenium, an essential dietary trace mineral for the good health of people, livestock, and, presumably, all mammals. The soil in parts of China where giant pandas live is known to be selenium deficient, which may mean that the bamboo they eat isn’t providing enough of this mineral. We will also look for correlations between nutritional composition of different bamboo species, and the pandas’ preferences, to see if pandas eat "what is good for them."

At the same time, our scientists and veterinarians will continue their collaboration in a long-term project to evaluate the health and the reproductive and genetic status of all of the giant pandas in zoos and breeding facilities in China.

As we work to bolster the zoo panda population, we can’t ignore the giant pandas and their habitat in the wild. Now and in the future, we need accurate and current information on the numbers, habitat needs, and range of pandas. Our focus will be in the Tangjiahe Reserve and, more broadly, the Min Mountains of western China, where we will map land use and critical habitat and conduct an ecological assessment of available panda habitat. In addition, we will develop techniques, such as satellite tracking, for monitoring the numbers and movements of wild giant pandas. One exciting plan is to perfect a procedure to determine the individual identities and sexes of giant pandas, without having to capture the animals, by analyzing DNA extracted from feces and hair samples. At the same time, we plan to expand the scope of monitoring to include the other species that share the giant panda’s habitat [see Under the Giant Panda Umbrella].

Supporting Roles

One of the most important roles we can play in giant panda conservation is sharing expertise with Chinese scientists and conservationists, and training Chinese students, field biologists, veterinarians, and wildlife managers in the most advanced conservation techniques and practices [see Training Conservationists]. An integral part of our research program will be including Chinese students and counterparts as partners, and rapidly sharing new information with Chinese colleagues. This is a tradition of National Zoo scientists working in other parts of the world, as is providing short-term training programs in areas from wildlife management to zoo biology and environmental leadership.

We also plan to assist efforts to inspire Chinese citizens to participate in efforts to save their country’s pandas, just as we are inspiring everyone who visits Tian Tian and Mei Xiang to want to do so as well. We know that science alone will not be enough to ensure that giant pandas survive in the wild well into the future. Without the support of those most intimately involved—the people who live near giant panda habitat whose needs must be met too—our efforts ultimately will not succeed.

The funds transferred to China to secure the loan of Tian Tian and Mei Xiang represent another important supporting role the National Zoo plays. This money, some $1 million a year for ten years, will be crucial to China’s implementation of giant panda conservation. For instance, in the first three years of the program, three important but currently under-funded Chinese giant panda reserves in Sichuan will be able to significantly upgrade facilities, education programs, and panda protection and monitoring activities.

Tian Tian and Mei Xiang will grow up in the months and years ahead, and, we hope, produce giant panda babies, adding to their resumes the job of prolific parents—as if ambassador, research assistant, fundraiser, and star weren’t enough. But then, this is Washington, D.C., where conservation leaders wear many hats as they strive to improve the outlook for the future of the natural world.

ZooGoer 30(1) 2001. Copyright 2001 Friends of the National Zoo. All rights reserved.

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