Panda Matchmaker

May 16, 2012

Simply put, panda mating is complicated, especially when the potential panda parents are just not that into each other. To date, male Tian Tian and female Mei Xiang have never produced a panda cub through the natural mating process. If the current attempt at artificial insemination fails, the Smithsonian's National Zoo may seek to swap out a panda or two. With only 333 captive pandas in the current gene pool, primary match disqualifications are inbreeding, old age and illness.

Jonathan Ballou, a geneticist with the Smithsonian Conservation Biology Institute, is tasked with finding suitable panda matches. He was online on Wednesday, May 16th to answer questions about pandas and other animals.

Welcome! I'm here to answer all your questions about pandas and animals. Lets get started.

The "mean kinship" formula that you use to calculate a panda's quality of match with another--where did that come from?

We actually developed for formula to manage the captive population of golden lion tamarins. The population was so large that we needed to find a way to easily identify the genetically most valuable individuals. Now this method is used in almost all captive breeding programs world-wide.

Do you ever have requests to match humans?

No!  I think it takes more than a pedigree to successfully match humans!

Is this matchmaking process used with all the zoo's endangered species? Or is it specific to just pandas? And why?

Yes - not only Smithsonian National Zoo's species, but most species' captive breeding programs use this process.

Has inbreeding been a problem in the past? What type of health problems can come from it?

So far, there is little inbreeding in pandas because we have been able to avoid it. But for many species where there is a small population size, inbreeding can be a big problem. Problems resulting from inbreeding are termed "inbreeding depression" and the health issues that result from inbreeding can vary widely. Inbred animals usually have higher mortality rate, lower reproductive rates, and many other deleterious effect.

When do you think you will know if Mei is pregnant ? Did you do anything different this year compared to other inseminations?

We won't know for a few months. There is no way to tell if she is really pregnant or pseudopregnant until the end of gestation.

How many pandas are needed to move them out of the endangered species zone?

The endangered status of a species is determined by the International Union for the Conservation of Nature (IUCN). There are a set of criteria that include population size, degree of fragmentation of the population, size of the area they inhabit, and risk of going extinct.

In the graphic, Pan Pan was listed as the "greatest panda daddy." Is he still alive and breeding?

Yes - he is still alive, but too old to breed. They think he was born around 1985 (he was born in the wild)

What is the most rewarding endangered species breeding project you have ever worked on?

Probably the golden lion tamarins - because the conservation work that was done for that species directly led to them being downgraded from being Critically Endangered to just Endangered. And someday soon, they may even be taken off the endangered species list. So that is a real success story.

Are you suggesting that the National Zoo and China are looking to replace either Mei or Tian, or both, if the artificial insemination fails this year?

We won't know until after the breeding season. Then we will be discussing options with our Chinese colleagues.

What other gene pools have you worked with -- other rare animals? Is it harder to work with pandas because so many of them are owned by the Chinese government?

Hmmm - lets see...  pandas, tamarins, California condors, black-footed ferrets,  - to name a few. No - not harder to work with pandas - we have a very good relationship with our Chinese colleagues and we work very closely with them.  We had two Chinese colleagues come to the zoo this breeding season to help us.


What makes pandas challenging is that in China females are often mated with several males (well, usually mated with one male but then artificially inseminated with sperm from other males as well). So determining which male is actually the real father of the cubs is tricky. DNA analysis have to be done to figure that out.

This maybe a dumb question but do you interact with the pandas much? Have you personally seen many of these pandas?

I have seen a few of them, but not all!

Can panda semen or ova be frozen for transport?

Yup. Actually we had frozen semen from Shi Shi, a male from San Diego (who is no longer living) - that could have used, but we didn't this year.

How many zoos in how many countries are a part of animal matchmaking programs?

Wow - all over the world. Don't know exactly. We manage the world population of golden lion tamarins and we have about 540 animals at 150 zoos around the world.

How long have you been a panda matchmaker? Was this your dream as a kid?

We bacame involved in panda match-making in 2001 and have worked with the Chinese every year since then.  I would never have imagined doing this when I was a kid! 


Working as a scientist at the Smithsonian is the best job in the world!

Do you know if the earthquake in China caused a set-back in their breeding program? Not only from the damage to facilities, but did the resulting stress cause any drop off in the females' cycles?

No - Surprisingly, I don't think the earthquake had much of an impact on the reproduction that year.

The kids and I are visiting the National Zoo in July. What animals are a must see?

The new family of otters are a must see!

What are some of the factors in your calculations for matches? I presume things like "likes to take long walks" is not a big consideration when seeking patches for pandas.

When doing matches, I provide the genetic information - are they genetically valuable, are the male and female unrelated.  Then the curators who know the individual animals take into consideration their age, health, previous breeding experience, behavior. So its a real team effort.

How have the Black-footed Ferrets done in captive breeding? I understand that there were fewer than 20 individuals in the progenitor population. That seems quite a bottle neck. Have you avoided the problems of inbreeding depression in that species? Do you ever remove an individual from the breeding population if you find a health problem that could be genetically significant?

The ferrets have done really well. you are right - the last 18 individuals of the species were brought into captivity to save the species. But the population grew rapidly.  They are really inbred, and there are some health related problems in some individuals, but the problems are not substantial enough to affect the overall population.

Ethically, I agree that we must do everything possible to preserve the giant panda. But have you ever considered the possibility that even if genetically two animals are matches for each other, in other ways they might not be? And that we could be somehow interferring with nature's plan? Tian Tian and Mei Xiang have never bred successfully on their own, have you ever thought that maybe there is a reason for that? And we shouldn't be introducing their genes?

In all species we find pairs that are incompatible for many reasons - often we don't know why a pair is incompatible. We usually then re-pair them with other mates. And sometimes that doesn't work.

Are you solely a geneticist or a zoologist too? I love the great ape house! Do you ever work with those animals?

Nope - never worked with the great apes.  But, like all captive breeding programs for endangered species, there is someone like me who oversees the genetic management of the population. For example, for orang utans, the genetic manager is a curator at the Atlanta Zoo.

If you suddenly had an unlimited research budget, what topic/species/problem would you most like to study?

What a fun question!  OK. Its this. Habitat destruction has caused many populations of animals to become small and fragmented. In small populations natural selection for the most part no longer works because which genes survive and which do not is determined by chance, not by the quality of the trait. So I'm really curious about the future of these populations that are not experiencing evolution through natural selection. What impact will that have on their long-term survival?

I think the National Zoo is my favorite zoo, do you work closely with any other American or International zoos when matching animals for mating?

Thanks! Yes - we work with many other zoos around the world. For example, in November I will be at the Taipei Zoo teaching a course on population management for Asian species.

What's your favorite memory of working at the National Zoo so far?

Probably participating in international training programs overseas.

We hear often about pseudo-pregnancy in giant pandas. Do we know for a fact that these are truly "pseudo" events with no fertilization, or is there resorption of a fertilized egg/fetus?

Not really my area, but our vets are pretty sure these are really pseudo pregnancies. We are trying to learn more about infertility in the pandas.

Thanks for the great questions!  Come to the zoo and see the pandas!

In This Chat
Dr. Jonathan Ballou
Jonathan Ballou is the population manager at the Smithsonian's National Zoo. As a conservation geneticist, his research career has focused on the genetic and demographic problems confronted by small populations, particularly small populations of endangered and threatened species.
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