Giant panda cubs are adorable, fuzzy balls of black and white fur. Zoo visitors regularly flock to catch a glimpse of these rarely seen animal stars. But when Jon I Ballou, from the Smithsonian Conservation Biology Institute, and Kathy Traylor-Holzer, from the IUCN SSC Conservation Breeding Specialist Group see panda cubs, they see them as a different kind of star. These cubs represent the future of giant pandas; future breeders that carry the genes of their wild-born ancestors needed to produce strong, healthy zoo populations and to support wild giant panda conservation. Dozens of questions are in their minds about each cub：Who is its mother and its father? Is it a single cub, part of a set of twins, or a rare triplet? Was it conceived through natural mating or artificial insemination (Al)? What role will it play in the larger picture of giant panda conservation?
Zoo animal populations can play significant roles in wildlife conservation, from increasing public awareness providing research opportunities, to serving as a source for reintroduction efforts, or even as an insurance policy against extinction. To be effective, however, zoo populations must be well managed to keep them genetically healthy and to avoid inbreeding.
Globally, giant pandas have received a lot of bad press about how poorly they breed. While this has been true of giant pandas in captivity for a number of years, today’s captive giant panda populations are growing quickly, averaging about 10% growth each year. This success is the result of the enormous dedication of Chinese and international colleagues working to improve husbandry, veterinary care, nutrition, and reproductive techniques. A major turning point was the formation of the Chinese Committee of Breeding Techniques for Giant Pandas in 2002, which meets annually to discuss challenges, goals, and, most importantly, develop the next year’s breeding plan for captive giant pandas around the world.
Enter the panda matchmakers Traylor-Holzer and Ballou. Fortunate to have been present at the formation of the Chinese Committee of Breeding Techniques for Giant Pandas in 2002, these population biologists have been advising on the Committee’s breeding master plan since its inception. Before the breeding season begins each year the first task of the committee is to update the studbook data which details information on the births, deaths, and other important events in between, for each captive giant panda. International studbook keeper Xie Zhong from the Chinese Association of Zoological Gardens is the committee’s data wizard, and soon passes the critical information to Ballou and Traylor-Holzer for a detailed analysis of what is necessary to keep the population healthy. The next step is for the committee to identify the goals for the population that year. Points for determining the goals may include how many pandas are needed for a healthy population, how fast should the population grow, and which pandas should breed and with whom.
At last the real work begins. Which giant pandas are the genetic “hot shots” and are priority breeders in the annual panda dating game? Results of the studbook data analysis guides the decision. Each panda is assigned a relative genetic value in the captive population, using a score called Mean Kinship (MK) developed by Ballou and used for most species in zoos around the world. A low MK score means that the panda has few relatives and is carrying a rare genetic line. This makes that panda a priority breeder. Pandas with high MK scores are not so lucky. Pandas that are not priority breeders in a given year may have offspring that are considered priority breeders due to the genetic profile they inherited from their mother and father.
After each female panda’s genetics are assessed, the committee chooses several males that make good potential matches for the next breeding season. Every effort is made to avoid selecting males that are related to the female, as inbreeding will likely produce unhealthy cubs and is detrimental to the population. Another score is calculated—this time it is a Mate Suitability Index (MSI) for each potential pair that combines genetic value and inbreeding considerations. Low MSI scores indicate good matches. Identifying multiple options for male mates is important, as some males are better breeders than others. AI is also an option to pass on a valuable male’s genes if all else fails. Genetic factors are important, but other factors such as health, age, temperament, and location are considered as well. Female by female, institution by institution, the matchmaking continues using the computer analysis as a guide. At the end of the long session of computer dating, a blueprint emerges for the next year’s breeding season.
This clinical approach to giant panda mating may seem unromantic, but because of it the captive giant panda population is healthy and thriving. Since the cooperative program began in 2002, the global captive giant panda population has increased from 152 to 375 living in 72 institutions, gene diversity has increased to 97.4%, and 92% of the captive population is captive born. Strong genetic management is keeping gene diversity high and inbreeding low, and is minimizing any genetic changes resulting from captivity. The long-term goal is to retain 90% of the giant panda population’s gene diversity for 200 years. This is an ambitious goal that will require an estimated total captive population of about 500 pandas. The global giant panda population is one of the most viable and healthy populations in captivity, and should be able to meet this goal as well as provide animals for release to support the wild panda population.
Although Ballou and Traylor-Holzer were recognized in this year’s Giant Panda Zoo Awards, they are quick to say that theirs is but a small role compared to the work of the global giant panda zoo and conservation community. This amazing and effective program is the result of immense effort and collaboration of zoo staff, nature reserve, staff, researchers, China’s State Forestry Administration, the Chinese Association of Zoological Gardens, and many other devoted colleagues both in China and around the world. “We feel honored to have been part of this success story for giant pandas, and to work with the wonderful and highly skilled biologists of China to assist them in their efforts to protect this very special species.” they said.