Maintaining the genetic diversity of giant pandas living in human care is a science–an exact science. SCBI scientist Jonathan Ballou determines how well-represented an individual panda’s genes are in the captive population and makes breeding recommendations. In this panda update he explains how he does it.
Before scientists can determine whose genes are well-represented and whose genes are underrepresented, they have to know how many pandas there are. The giant panda studbook contains the genealogy of all 341 pandas living in human care. It is updated with the latest births, deaths, and moves of every giant panda. The pandas that are too old or unhealthy to breed are identified and removed from any genetic analysis. Two years ago, 30 pandas were identified as unfit for breeding. That left the genetic population at 303 bears.
At the Smithsonian’s National Zoo–and at other zoos where there are only two pandas–the female can only breed with one male. In China, where there are many pandas living in the same facility, a female can breed with several males, or be artificially inseminated with sperm from several males. In cases where the paternity of a panda cub may not be known, we make assumptions about paternity. Although molecular genetic paternity testing is available, it usually takes a while and cannot always confirm who the father is. In 2011, there were about 60 pandas with uncertain paternity. But we have found a way to compensate for that.
The software we now use allows us to give probabilities of certain males being the father of the cub. For example if a female was artificially inseminated with sperm from male A and male B, we know that there is a 50 percent chance the father is A, and a 50 percent chance it is B. Our genetic calculations can then credit both A and B, but they only get one-half credit each.
After we have established the probability of paternity, we run the program to calculate the mean kinship values. The mean kinship of an individual is the average kinship (a measure of genetic relatedness) between him/herself and all the pandas in the genetic population. Pandas with lots of relatives have high mean kinship values. They are not considered as genetically valuable because their genes have copies in their relatives. They are not genetically unique.
Based on mean kinship for each male-female pair in the population, we also calculate something called the Mate Suitability Index. The Mate Suitability Index is a numerical ranking from one to six. The ranking reflects how offspring from that pair would affect the overall genetics of the population. Ranks of 1, 2 and 3 indicate that the genetics of the offspring benefit the population, with one being the best. Ranks of 4, 5 and 6 mean that the genetics of the offspring are detrimental to the population. When we say that the genetics of the offspring are detrimental, we mean that they may be inbred higher than the average level of inbreeding in the population, or their genes may be overrepresented.
Tables of the MSI values for each potential pair are distributed to the institutions holding the pandas. Based on the curator’s knowledge of the age, behavior, health of the pandas, and their MSI ranking the institutions then select which males to be bred with which females. They usually pick several different males for each female so they have options come breeding time.
We have some exciting news for all of our panda cam watchers! The panda cams, sponsored by the Ford Motor Company Fund, are going to be gradually ugraded. But in order to make the changes the cams will be turned off for a few weeks. The cams will most likely go dark around at the end of May and come back online in mid-June. We will finish the upgrades before Mei Xiang begins to build her nest and den up in preparation for the end of breeding season.
Soon the panda cams will be compatible with all iPad, tablet and smartphone devices. We also hope to do away with the 15-minute time limit on the cams, and offer an unlimited video stream. After we have finished these upgrades, there is even a possibility of upgrading to HD cameras in the dens!
A little over a week ago we were very saddened to learn of the severe earthquake in China. We are happy and relieved to confirm that our colleagues at the Bifengxia panda reserve and the giant pandas in their care are all safe, including Tai Shan the male offspring of Mei Xiang and Tian Tian born in 2005.
Both Mei Xiang and Tian Tian are returning to their normal routines, following the breeding season. Occasionally, we are still seeing some scent-marking or some restlessness, but their appetites have returned, and both are spending their days exploring their yards independently, with little interest in what the other is doing. While giant pandas live in proximity to each other in the wild, they rarely interact socially aside from breeding season. They communicate to each other via scent-marks along trees and large rocks, indicating their identity and reproductive status to other giant pandas in the area.
Sometime in June, we will expect to see Mei Xiang starting to den up in preparation for the birth of a cub or the end of a pseudopregnancy. Since giant pandas experience delayed implantation, their gestation can be anywhere from three to six months. We will continue to monitor Mei’s behavior and hormones, watching anxiously for her hormones to enter their secondary rise. This will alert us that we only have a month or two to wait until we know whether or not all of our efforts have resulted in a healthy giant panda cub.
This week’s Giant Panda Update is from Mike Maslanka, head of the Department of Nutrition Science at the Zoo.
It’s 6:15 a.m. It’s dark and cold outside. Many folks around D.C. are still arguing with the snooze button. But in the morning darkness, the garage door of the Commissary at the Smithsonian’s National Zoo slowly opens and a truck full of bamboo rolls out for the early morning bamboo delivery. This scene is repeated 365 days a year.
The Department of Nutrition Science at the National Zoo is responsible for providing diets for every animal living at the Zoo every day – and that of course includes our two giant pandas, Mei Xiang and Tian Tian. It sounds simple enough – cut some bamboo and deliver it to the David M. Rubenstein Family Giant Panda Habitat – but the process is actually a bit more complicated.
Even though pandas also get a small amount of produce and a biscuit, the majority of their diet is bamboo, and the need for bamboo never stops. Until about two weeks or so ago, the pandas were offered a little over 100 pounds of bamboo each day. We don’t know how many different species of bamboo giant pandas eat in the wild, but we have found that Mei Xiang and Tian Tian have eaten five or six species well. Satisfying giant appetites like that takes much more bamboo than we grow at the Zoo or the Smithsonian Conservation Biology Institute. We harvest bamboo from nearly 20 different sites around the Washington, D.C. area. The harvest locations range from historic sites (those we’ve used for 20 years or more) to more recent finds (locations we have found in the last five years). All together our bamboo stands encompass probably 14 to 15 hectares (which is between 35 and 37 acres).
All of the bamboo we feed to all of our animals has to meet stringent animal care standards. Prior to harvesting, we sample each stand of bamboo to ensure it is safe. We examine not only nutrients, but also potential contaminants that could be on or in the bamboo. The location of the bamboo stand is also important when determining if the bamboo growing on it is safe for our animals. We take into consideration if there is any pollution in areas around the bamboo stand, and we have to make sure the stand is safe to work in and around. Since the pandas and many of our other animals need bamboo every day, we also don’t want to harvest an entire stand at once. So, we typically don’t harvest from stands smaller than a full acre.
We want to have stands to harvest from for many years to come. We can’t harvest too much from a single stand without having negative impacts on stand health and regrowth, so we rotate between all of our stands. The support that we receive from the community helps us care for and keep our pandas healthy.
Reproductive scientists and veterinarians from the Smithsonian’s National Zoo alongside Tang Chunxiang, the assistant director and chief veterinarian of the China Conservation and Research Center for the Giant Panda at Wolong performed a second artificial insemination on giant panda Mei Xiang Saturday, March 30, around 6 p.m.
During the first artificial insemination scientists used a combination of fresh and frozen semen from Tian Tian. For the second procedure, Mei Xiang was artificially inseminated with frozen semen from two different males.
Scientists used thawed semen collected from the San Diego Zoo’s male giant panda, Gao Gao, in 2003. They then used thawed semen collected from Tian Tian in 2003. Mei Xiang was inseminated with semen from Gao Gao in 2007, but she did not give birth to a cub.
A wild-born male giant panda, Gao Gao arrived at the San Diego Zoo on Jan. 15, 2003, from the People’s Republic of China as part of the Zoo’s research loan. He was born in China’s Baoxing County but was kept in the Fengtongzhai Rescue Center for most of his early life after reintroduction efforts failed to keep him out of areas inhabited by humans. He was transferred to the Wolong Nature Reserve prior to his journey to the San Diego Zoo. Gao Gao had shown interest in female pandas in Wolong; however, he had not fathered any offspring until his arrival in San Diego. He is the sire of five cubs born to Bai Yun at the San Diego Zoo: Mei Sheng, Su Lin, Zhen Zhen, Yun Zi and Xiao Liwu.
Both Mei Xiang and Tian Tian have recovered from the procedures over the weekend and are doing well. The Zoo will run a paternity analysis if a cub is born. The David M. Rubenstein Family Giant Panda Habitat reopened to the public yesterday, March 31, and visitors can see both Mei Xiang and Tian Tian.
Spring has sprung and the giant pandas are breeding again at the Smithsonian’s National Zoo. Scientists detected a rise in urinary estrogens March 26, in its female giant panda Mei Xiang (may-SHONG). This rise and her behaviors indicated that Mei Xiang was in estrus and ready to breed. A team of Zoo scientists and veterinarians, including Tang Chunxiang, the assistant director and chief veterinarian of the China Conservation and Research Center for the Giant Panda at Wolong, performed an artificial insemination (AI) earlier this morning after keepers determined no competent breeding between Mei Xiang and the Zoo’s male giant panda Tian Tian (tee-YEN tee-YEN) had occurred overnight.
"We are hopeful that our breeding efforts will be successful this year, and we’re encouraged by all the behaviors and hormonal data we’ve seen so far," said Dave Wildt, head of the Center for Species Survival at the Smithsonian Conservation Biology Institute. "We have an extremely small window of opportunity to perform the procedures, which is why we monitor behavior and hormones so closely."
Mei Xiang was put under general anesthesia for the artificial insemination and will likely undergo a second procedure later today. During the artificial insemination, the team of scientists and veterinarians used a combination of fresh semen collected from Tian Tian early this morning and frozen semen collected from Tian Tian in 2003.
The Zoo will provide further updates through its Facebook page and Twitter using the hashtag #PandaAI.
The David M. Rubenstein Family Giant Panda Habitat, which has been closed since March 26, will reopen tomorrow, March 31. Visitors to the Zoo today should not expect to see the pandas. In the meantime panda fans can watch Mei Xiang and Tian Tian on the panda cam, sponsored by the Ford Motor Company Fund, except during an artificial insemination.
The Zoo’s plans for breeding Mei Xiang and Tian Tian were developed in accordance with the Giant Panda Cooperative Research and Breeding Agreement, which lasts until 2015. Tang traveled to the Zoo to assist with breeding as part of the agreement. He performed two artificial inseminations on Mei Xiang alongside a team from the Zoo in 2011.
Zoo scientists will monitor Mei Xiang’s hormone levels in the coming months and conduct ultrasounds to determine if she is pregnant. A pregnancy lasts between 95 and 160 days. Female giant pandas experience delayed implantation, during which the embryo does not implant in the uterine wall until a few weeks before birth and a fetus does not start to develop until the final weeks of gestation. It is impossible to determine from behaviors and hormone analyses alone if a female is pregnant or experiencing a false pregnancy (pseudopregnancy).
The Zoo received approval for its breeding plans from the China Wildlife and Conservation Association and the U.S. Fish and Wildlife Service, which monitors giant panda research programs in the United States.
Breeding season has arrived! Mei Xiang and Tian Tian are exhibiting behaviors indicating that they are ready to breed; and Mei Xiang's hormones have begun to rise. That rise indicates that she is in estrus. Our giant panda breeding team — including Zoo keepers, reproductive scientists, veterinarians and Chinese colleagues — is in place and waiting. Mei Xiang and Tian Tian will have an opportunity to breed naturally, but if no competent breeding is observed then the team will perform one or more artificial inseminations. Zoo scientists are monitoring Mei Xiang's behaviors and hormones, and will identify the best time to perform an artificial insemination in the coming days.
The David M. Rubenstein Family Giant Panda Habitat will be closed until Mei Xiang is no longer in estrus, but visitors ocassionally may be able to see one or both bears in their yards from Asia Trail. In the meantime the best place to watch Mei and Tian is on the panda cam, sponsored by the Ford Motor Company Fund. However, the cam will be turned off if the panda team is performing an artificial insemination. We will provide updates on breeding efforts on the Zoo's Facebook page and its Twitter page using the hashtag #PandaAI.
This week's giant panda news features a behavior update from keeper, Nicole MacCorkle.
Both Mei’s and Tian’s appetites have decreased a bit this week. Tian is bleating more at Mei (a high pitched contact call), and she is vocalizing back, although her vocalizations are anything but friendly. She answers back with a low pitched moan, indicating that she’s not quite ready for breeding, even though things are proceeding in that direction. In the coming days, we expect to see Mei’s behavior shift, with her bleating at not only Tian Tian, but also at keepers, indicating that estrus is imminent. In the meantime, we are collecting daily urine samples and vaginal cytology slides, and carefully monitoring both Mei’s and Tian’s behaviors.
Mei and Tian have been spending more time interacting with each other at the mesh that separates their yards lately. Unfortunately, they have been choosing to do that near the back of the yards which has made it difficult to see them when they are outside at the David M. Rubenstein Family Giant Panda Habitat. Even if they may be difficult to see in the yards, panda fans can watch Mei and Tian on the panda cam, sponsored by the Ford Motor Company Fund, anywhere!
We are continuing to monitor Mei Xiang’s hormone levels very closely, but her hormones are still at baseline. Once Mei Xiang’s hormones begin to rise we will know that she has entered estrus. Though she is still in the pre-estrus phase, Mei has started showing increased activity and we have noticed some physiological changes. Mei is not the only one getting a little restless. Tian Tian is showing some rutting behaviors; he is power-walking around his exhibit. All the signs indicate that we are getting closer to the first phase of breeding season.
Dr. Pierre Comizzoli is a reproductive cryobiologist at the Smithsonian Conservation Biology Institute. In this giant panda update he explains how the Zoo stores semen for endagered wildlife, which can be used for procedures like an artificial insemination.
The team of people at the Zoo who study and research giant panda reproduction includes keepers, veterinarians and scientists. I am one of the scientists on that team, specifically a reproductive cryobiologist. That means that I am a specialist in the preservation of sperm cells, eggs and gonadal tissues of endangered species at freezing temperatures.
By freezing semen samples of endangered species we preserve them for long periods of time and can suspend the life of sperm for decades. At the Zoo we store frozen semen of giant pandas and other species in the sperm bank. It is critical to create frozen sperm banks because the genes from deceased individuals can be used to produce offspring long after their death. This is really important for the sustainability of small populations and it is integrated with other conservation efforts. When we need the frozen sperm cells, we thaw them and then they can be used for assisted reproduction (like an artificial insemination). The Zoo’s sperm bank contains more than 2,000 semen samples from more than 100 species. Sixty of those samples are giant panda semen from five males.
Our two pandas at the Zoo, Mei Xiang and Tian Tian, have never successfully bred on their own. For a critically endangered species like the giant panda – that presents a challenge for conservation efforts, which is why we perform artificial inseminations on Mei Xiang when natural breeding does not occur.
I have been involved with performing giant panda artificial inseminations at the Zoo every year since 2004 – except in 2006 when Mei Xiang was nursing Tai Shan. For some artificial inseminations we have used frozen sperm, which is stored in the Zoo’s sperm bank.
We only freeze semen from endangered species that is high-quality. The process for freezing samples is very specific to ensure that the samples are the highest quality possible. First, the semen has to be mixed with a solution that prevents pH variations, otherwise those variations would kill the small and fragile cells. Then, an ‘anti-freeze’ agent (glycerol) is added to the diluted semen to protect the cells before being exposed to decreasing temperatures. Ideally the semen is first cooled to 4°C, which is the temperature of a refrigerator, in a couple of hours. The cold semen suspension is then loaded in small plastic straws that hold less than 1/4mL of semen. All of the straws hold the same concentration of semen. Finally, the straws are exposed for several minutes to liquid nitrogen vapors at a temperature of about -100°C, before being plunged in the liquid nitrogen (-196°C).
We don’t always have to use frozen sperm for giant panda artificial inseminations. We can use fresh samples, but only high-quality fresh semen. We know if fresh semen is high-quality based on how many moving spermatozoa are in the sample. After we collect a fresh semen sample, it has to be either used for an insemination or frozen immediately otherwise the sperm cells start to die (they stop moving). The forward motility of the sperm cells (which we can see using a microscope) is the best indicator of their quality and viability.
In addition to the research Zoo scientists and their Chinese colleagues conduct on giant pandas, they also study red pandas. In this update Dr. Copper Aitken-Palmer, lead veterinarian at the Smithsonian Conservation Biology Institute’s Department of Conservation Medicine, writes about the research Zoo scientists are currently doing with red pandas.
In November the Smithsonian Conservation Biology Institute launched the largest health and reproductive study ever on the red panda. This study is evaluating the largest red panda population housed under human care at the Chengdu Research Base of Giant Panda Breeding (Panda Base) in Chengdu, China. A significant number of the red pandas at the Panda Base are involved in the study. SCBI’s Department of Conservation Medicine is working with experts at the Panda Base and George Mason University to conduct a biomedical survey of red pandas.
The red panda is the only member of the family Aluridae making it a unique species unlike any other carnivore on the planet. Although a very different species than the similarly named giant panda, red pandas share their habitat with the giant panda. SCBI is interested in evaluating diseases of special species that share habitat with the giant panda, specifically in the Sichuan region of China, as part of a broader project initiated by the SCBI’s Department of Conservation Medicine called the Giant Panda Comparative Medicine and Disease Susceptibility Initiative. Our red pandas at SCBI’s headquarters in Front Royal, Virginia are also in the study. Five red pandas live at SCBI in Front Royal and one red panda, Shama, lives at the Zoo. Chengdu houses the most red pandas of any facility in the world.
Dr. Copper Aitken-Palmer is the lead veterinarian at the Smithsonian Conservation Biology Institute's Department of Conservation Medicine. In the past few months she and other Zoo scientists have traveled to China for different giant panda conservation initatives. Below she writes about some of their trips.
The past few months have been very busy. In November I traveled to China with Dr. Elizabeth Freeman from George Mason University, thanks to a donation from the Ford Motor Company Fund, for the annual Giant Panda Technical Meeting in Chengdu, China. The Technical meeting is a two-to-four-day meeting that is hosted annually in China. All of the giant panda scientists worldwide go – which is probably around 100 people. During the meeting we participated in discussions with giant panda experts in China on current reintroduction projects, emerging giant panda health concerns, and reproductive studies. Chinese scientists are working exclusively on the reintroduction projects, but it was interesting to hear what they have been doing. Last year one young male panda was introduced into the wild. He was born in captivity, but his mother was born in the wild. That was part of a CWCA (Chinese Wildlife Conservation Administration) project. And one of our very own SCBI scientists, Jon Ballou, talked about giant panda genetics. Each presentation was given in both English and Chinese thanks to the help of translators. My presentation was translated simultaneously into Chinese as I was speaking.
In December, the month after the Giant Panda Technical Meeting, David M. Rubenstein Fellow Andrea Lee traveled to China to present the preliminary results of the giant panda parasite study conducted with Chinese veterinary experts in giant panda health. This study was conducted during the fall of 2012 at Bifengxia Giant Panda Center (CWCA). Round worms are the biggest problem we have found, but we will continue to conduct parasite studies for the next five years. Additionally, she continued collecting red panda health data working with veterinarians at the Chengdu Research Base of Giant Panda Breeding.
Last month Kendall Bilbrey, a graduate of the Smithsonian-Mason School of Conservation, joined the SCBI team to continue data collection for the Ford Motor Company Fund’s Giant Panda Comparative Medicine and Disease Susceptibility Initiative. This is a long-term collaborative effort between CWCA, SCBI's Department of Conservation Medicine and George Mason University to learn more about health and disease of the giant panda.
Finally, this month I started working with Andrea Lee, a veterinary biotechnologist, and Kendall Bilbrey in preparation for a trip to China in March. This trip will be part of the Ford Motor Company Fund’s Giant Panda Comparative Medicine and Disease Susceptibility Initiative. We’ll keep you updated on our research in the coming months!
Over the next few months we’ll be bringing you giant panda updates that will focus on Mei Xiang and Tian Tian, and the research Zoo scientists conduct related to giant pandas around the world. You'll be hearing from many different experts at the Zoo and the Smithsonian Conservation Biology Institute. The update below about Mei Xiang and Tian Tian was written by giant panda keeper Nicole MacCorkle.
We are starting to see slight changes in Mei Xiang’s and Tian Tian’s behavior, as well as some physical changes. There have not been any changes in Mei Xiang’s hormones, yet, however. This information, taken together, and compared against previous years’ data, tells us that breeding season will most likely be between mid-March and Mid-April, if things continue along the current trajectory. Keep in mind however, that this is only an estimate, and that a female giant panda’s estrus can vary greatly from season to season, as Mei Xiang has shown us in the past. Our breeding plan for this year is the same as last year.
We're entering this 2013 breeding season with renewed optimism. Mei Xiang has proven that an older female who hasn’t had a cub in many years can indeed become pregnant. She also reminded us that she continues to be an excellent mother.
In the spirit of Valentine's Day watch a special video from Juan, a giant panda keeper at the Zoo, explain about breeding season at the Zoo! If you're looking for the perfect valentine for the love of your life, you can send them a giant panda Critter Cupid complete with the video, a beautiful photo and a personalized message. Valentines for your otteragous family, sea lion best friend, firefoxy single friend and your tiger "amour" are also available. Each Critter Cupid is $10 and all proceeds support the Zoo.
Seven days and counting. . .
If you’re a panda fan or if you know a panda fan – we have the perfect Valentine’s Day gift for you! Send a giant panda Critter Cupid – complete with a special video featuring Mei Xiang, Tian Tian and one of our panda keepers! In the video, Juan tells the story of Mei and Tian, their version of “love notes,” and he talks about how we care for the bears. Each e-valentine comes with a beautiful photo of Mei and Tian, and a personalized note from you.
Certainly more unique than a box of chocolates or flowers — tell someone special how in love you are, with Mei Xiang and Tian Tian’s help! All proceeds from each $10 Critter Cupid support the Zoo! Happy Valentine’s Day!
Please note giant panda Critter Cupids are recommended for adults, as breeding is discussed in the video message. Other species, including California sea lion and Asian small-clawed otter Critter Cupids are available to send to children, family or friends.
Mei Xiang’s den has been transformed for the new breeding season! Observant panda cam viewers have no doubt seen the difference in the configuration of the barred barriers. By shifting the angle of the bars, keepers will be able to have more direct access to Mei Xiang and future cub(s) while they are resting in the nest area. The old bars were recycled, making the renovations not only a little greener, but also a little less overwhelming for Mei Xiang. It was as if the “furniture” was simply rearranged one day.
Keepers are now working on desensitization training (getting her used to the new set up, and getting her comfortable having keepers in close proximity to her while protected by the new barrier). As we had hoped, Mei Xiang is barely fazed by the changes, and is now regularly participating in training sessions in the remodeled den.
One of the biggest questions scientists at the Smithsonian Conservation Biology Institute (SCBI) were working hand-in-hand with their colleagues in China to understand in the late 1990s was: why are pandas ‘challenged’ at reproducing? Almost a decade later, scientists are still answering questions about giant panda reproduction, but a new generation of scientists are now also contributing to scientific breakthroughs.
It was during the late 1990s while surveying the major panda breeding sites in China that SCBI researchers first met Yan Huang. “We met this eager young investigator who wanted to learn more about improving reproductive health and consistency in giant pandas,” says David Wildt, head of SCBI’s Center for Species Survival. Wildt and the late Dr. JoGayle Howard began working with Yan.
Under their guidance Yan learned many new methods for improving panda reproductive health and success. They included collecting and freeze-thawing sperm, which are vitally important for artificial inseminations (AIs) and effectively managing pandas. Yan trained at SCBI’s campus at the National Zoo in Washington, D.C. and its headquarters in Front Royal, Va., and in China.
Once a student, Yan is now making his own advances in giant panda research. Recently the premier reproduction journal, Biology of Reproduction, published an article about improving reproductive success in pandas. Yan was the lead author of the paper that details how to determine the exact date to perform an artificial insemination. He worked with his Chinese colleagues on his research, and Wildt was a collaborator. Knowing exactly when to perform an artificial insemination on a female giant panda is very important. Female giant pandas come into estrus for 24 to 72 hours each year, which means scientists only have one brief window of opportunity to perform an AI.
Yan tracked reproductive hormones in urine and used DNA paternity analysis to determine the best time to perform an AI on a female panda. He found that the best day to do an AI coincides with the peak day of urinary estrogen production. Based on the DNA paternity analysis, Yan saw that the male whose sperm was used for an AI on the peak day of urinary estrogen production in the female was the father of the female’s cub. “So,” Wildt explains of Yan’s research, “it’s all about timing. Doing an AI later in the short estrus is not worthwhile or a good use of frozen sperm.
Yan is now a leader in developing new and novel methods for reintroducing pandas into the wild in Sichuan Province. “Huang Yan is a perfect example of what we are doing at SCBI – creating scientists with multiple skills – working towards training ourselves right out of a job”.
One of the National Zoo’s goals is to train future generations of conservationists, who will make the next major advances in conservation science. This capacity-building extends across many species, ecosystems and scientific disciplines, and has resulted in powerful collaborations and important studies, including for the iconic giant panda.
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