Smithsonian National Zoological Park l Friends of the National Zoo



2012 Panda Updates

November 20

In the United States and Canada there are about 180 red pandas in zoos. The red panda Species Survival Plan (SSP) keeps track of each of them and pairs them up for breeding to ensure a sustainable zoo population. The SSP meets once a year to draft a master plan—the document that lists the year's breeding and transfer recommendations for the species. This year's meeting took place in August at the Knoxville Zoo.

The SSP coordinator, who oversees the SSP and is considered the AZA expert on red pandas, and the studbook keeper, who keeps the official pedigree and demographic record of each animal in the population (known as the studbook)run the meetings.  While every species master planning meeting is different, the goal is the same—solve the complicated puzzle of who will breed with whom and who will live where. At this meeting, each red panda was represented by a magnet, color-coded for sex and labeled with the animal’s name and studbook number. We moved these magnets around on large magnetic boards hung on the wall. Each board was divided into squares, and each square represented a zoo or institution.

red panda

Over three days, we moved magnets from one square to another, frequently matching two animals for breeding and considering the genetic outcome. The SSP coordinator and studbook keeper know each red panda’s history, behavior, and genetics. Sometimes the outcomes of a potential match were simply talked through, and sometimes the match’s “numbers” were run through a computer program that uses population management software—this gave an exact calculation of how closely related each animal is to the rest of the population (mean kinship) and how the pairing would affect the genetic diversity of the population.

When considering pairings, the SSP takes more than math into consideration. They also think about:

  1. The wants and needs of each zoo. Some zoos may want a breeding pair or a cub, or they may ask to move an animal they currently have to another institution.
  2. The available exhibit and/or holding space available at each zoo.
  3. The behavior of each red panda. Will two animals get along or can a particular institution cope with an individual who has a history of behavioral issues?
  4. Breeding success of red panda pairs. The SSP tries to keep pairs together for at least two years, but they also keep in mind that if the same pair has been breeding for a while, their offspring may have become over-represented in the population. Similarly, if a pair has been together for a few years and not bred successfully, it could be time to try a new pairing.
  5. Ease of transfer. Shipping a red panda from Washington, D.C., to Philadelphia is certainly easier and less stressful than shipping a red panda from Washington, D.C., to Seattle, and the SSP takes this into account.
  6. Age. Post-reproductive animals are usually left where they are.
  7. Weight. Because weight affects breeding success in red pandas, overweight animals may be sent to zoos that have successfully been able to help animals lose weight. When separating pairs, the SSP tries to leave breeding females where they are and move the males. This mimics what would happen in the wild, giving the red pandas their best opportunity for successful breeding

The result of the meeting is a draft master plan. In it, each red panda is assigned a recommendation for the year. This may be HOLD (stay where it is) or TRANSFER (and to which institution), and it may be recommended to BREED (and to which animal) or NOT BREED.

The results of the master plan this year could mean exciting developments for the National Zoo! We’ll keep you updated.

October 22

We would like to again thank the visitors and panda fans from around the world who have sent condolences during this difficult time. The kind words and cards, especially those from the littlest panda fans, have helped to brighten the mood at the David M. Rubenstein Family Giant Panda Habitat. As keepers, we were excited for Mei Xiang to experience motherhood again and for Zoo staff and visitors alike to experience all of the joy that a growing giant panda cub brings. But now we look toward the future. Mei is completely back to normal. She’s been eating all of her bamboo and produce.

Over the past several months a few of our veterinarians and scientists have traveled to the new Wildlife Disease Control Center site in China. We’ll bring you their stories from the field and news about giant panda conservation work in China in our upcoming updates. Stay tuned!

October 11

Our pathologists have finished the final necropsy on Mei’s cub, and the panda team shared the results this morning. The initial necropsy, which was performed on September 23, showed that the week-old female cub had fluid in her abdomen and her liver was hard in places. There were no signs of internal or external trauma. The final necropsy determined that lung and liver damage ultimately caused the cub’s death. Her lungs were poorly developed and likely caused her to have insufficient oxygen, which would be consistent with the changes in the liver. The mortality rate for pandas in their first year in captivity is estimated to be 26 percent for males and 20 percent for females. Some early mortality rates may be underestimated.

We are working with our colleagues in China to answer questions about giant pandas that will ensure the best care in captivity and that will help bolster the species’ numbers in the wild. The information about how this cub died will add to the scientific body of knowledge about giant pandas. The Zoo will continue to work closely with its Chinese colleagues and share the information it has learned about giant panda reproduction and cub health.

Many of you have been asking about what our plans are for Mei and Tian. No decision has been made about their future. Our current agreement with China lasts through December 5, 2015 and stipulates that the Zoo will conduct research in the areas of breeding and cub behavior. Panda fans can still watch Mei and Tian on the panda cams every day.

We are happy to report that Mei is almost completely back to her old self! Her hormones have returned to normal levels, as has her behavior. Mei is choosing to go outside in the mornings. In the afternoons she can usually be found napping on her indoor rockwork. Mei’s appetite has also returned, and she is eating almost all of her bamboo and all of her leaf eater biscuits and produce. The David M. Rubenstein Family Giant Panda Habitat is open, and visitors can see Tian Tian and Mei Xiang outdoors and indoors, though the area directly around Mei’s den is still closed. The panda team expects that the entire David M. Rubenstein Family Giant Panda Habitat will be open soon, as Mei has not shown any sensitivity to noise lately.

Keepers cleaned the bamboo out of Mei’s den on Wednesday since she no longer spends much time there. Months ago, we installed a time-lapse camera in Mei’s den before she started building her nest in hopes that for the first time, we would have a visual record of how she built her nest. We retrieved it from the den this week. Unfortunately, we had some technical difficulties so it did not work out exactly as planned. Even though the progression is not as detailed as we would have liked, the photos still show some of Mei’s nesting. You can watch the time-lapse video made from the photos on our YouTube page.

October 2

Mei Xiang is slowly settling back into her regular routine. She ventured into her outdoor enclosure on Saturday for the first time since we lost the cub, and briefly this morning and yesterday morning. She also made a brief appearance for the keeper talk inside the David M. Rubenstein Panda Habitat on Monday afternoon, though she still chooses to spend most of her afternoons in her den. Her appetite is gradually returning; she has been eating noticeably more bamboo and produce.

The David M. Rubenstein Family Giant Panda Habitat partially reopened over the weekend. Mei could still be sensitive to noise, so visitors may not be able to see her indoors just yet. However, since Mei’s behavior and appetite are returning to normal, the panda keepers expect to fully reopen it soon. Visitors are able to see Tian Tian and Mei Xiang in their yards, and Tian Tian indoors.

We are still waiting for final necropsy results on Mei’s cub. As soon as we have more information we will share it with you.


The entire panda team would like to express their gratitude for the overwhelming amount of support and condolences we have received from the public during this difficult time. We have gotten many questions about how to send messages to the keepers in the past week. The best way to get a message to the panda team is through the Zoo’s Facebook page and the FONZ Facebook page. You can also send them an email. Some supporters have expressed interest in making a memorial donation to help the Zoo's giant panda conservation efforts. If you are so moved, please donate to the Giant Panda Conservation Fund here.

September 24

We’re still reeling from the loss of our giant panda cub, and we feel like the whole world is mourning with us. Our staff is anguished, which is to be expected. Every loss is hard but this one is especially devastating. Thank you so much for your outpouring of support. Your sentiments of support and understanding of our work helps tremendously when we have to get through tough times like this.

We still don’t know definitively what caused us to lose the giant panda cub yesterday, but we do have some more information since yesterday, especially from the necropsy (animal autopsy).

The giant panda cub appeared to be a female. She weighed a little less than 100 grams, which is about four ounces. There were no signs of trauma, external or internal, which means that she was not crushed—confirmation that Mei is a good mother. Her heart and lungs also looked good, which tells us that she did not suffocate. There was a little milk in the cub’s gastrointestinal tract, which tells us that she did successfully nurse. The only abnormalities the veterinarians have detected so far were some fluid in her abdomen and a slightly abnormal liver. They don’t know yet whether either of those things is significant, and they’re still investigating.

The panda team continues to monitor Mei Xiang, and will until she returns to her normal behavior. She appeared to sleep well last night. Watchers did notice her cradling an object, as she did before to the birth of the cub. We believe this is an expression of her natural mothering instinct.

Mei is moving around well this morning, and the panda team was able to weigh her.  She weighs 217 pounds, which is less than her regular weight but perfectly normal for a mother who hasn’t eaten in a while. (Mei had not left her den in over a week.) She ate a little this morning and drank some water. The panda team was able to get a vaginal culture from her, which they will check for signs of anything unusual. Once the tests results come back and we’re certain of her health, we will give her access to her outside yard and it will be up to her whether she wants to go outside. We fully anticipate that she’ll return to her normal wonderful giant panda self in a relatively short amount of time. Once she is out of her den and acting normally, we will open the Panda House. We’ll keep the panda cam on so our supporters and fans can continue to watch from around the world.

Many of you have asked about the future of these two bears at the Smithsonian’s National Zoo. Today, our immediate concern is for Mei Xiang’s well-being, and to understand what happened to the cub. We spoke to our Chinese colleagues yesterday and will continue to work very closely with them over the next few months. However, no decisions will be made until we have thoroughly discussed all options.

We will learn from this tragedy and hope we will gain a better understanding of giant panda reproduction and cub health as a result. Our next steps will be to share the information we’ve learned with our Chinese colleagues. We’ll continue to try to figure out what caused the cub’s death through microscopic and histological evaluation. As we know more, we’ll share it with you.

September 23

We are brokenhearted to share that we have lost our little giant panda cub. Panda keepers and volunteers heard Mei Xiang make a distress vocalization at 9:17 a.m. and let the veterinarian staff know immediately. They turned off the panda cam and were able to safely retrieve the cub for an evaluation at 10:22 a.m., which we only do in situations of gravest concern. The veterinarians immediately performed CPR and other life-saving measures, but sadly the cub was unresponsive. We’ll have more updates as we learn more, but right now we know is that the cub weighed just under 100 grams and that there was no outward sign of trauma or infection. We’ll share information with you as we learn more.  

September 18

Glimpse of the Smithsonian’s National Zoo’s Panda Cub
Smithsonian’s National Zoo staff and Panda Cam watchers have gotten several quick glimpses of female giant panda Mei Xiang’s cub. In this video, Sept. 17. at about 8:35 p.m. EST, Mei Xiang cradles the newborn and gently picks it up in her mouth as she shifts position. This is normal behavior and another sign that Mei Xiang is being an excellent mother to her new cub. By using her mouth, Mei Xiang can very gently and dexterously position her cub on her body so that she is able to nurse and groom it.

The cub actively squirms and vocalizes loudly in response—two good signs that the cub is healthy! Keepers report that Mei Xiang is exhibiting excellent maternal behaviors. She is prompt to cradle and groom the cub, and there is evidence that it is successfully nursing. The Zoo will continue to diligently monitor both bears over the Panda Cam and minimize disturbances around their den.

September 17

As panda cam watchers may have noticed: from Mei's behavior and the sounds we're hearing, we have a giant panda cub!

As far as we can tell, the cub was born at about 10:46 p.m. on September 16. According to chief veterinarian Suzan Murray:

“Mei Xiang is behaving exactly the same way she did when Tai Shan was born. She is cradling her cub closely , and she looks so tired, but every time she tries to lay down, the cub squawks and she sits right up and cradles the cub more closely. She is the poster child for a perfect panda mom.”

We believe there is only one cub. If the cub is to have a twin, we should know by sunrise.

For now, the only way animal care staff will monitor the cub is using the web cams. Our goal is for Mei Xiang to raise this cub naturally. With Tai Shan, it wasn’t until he was about two weeks old that Mei walked away from him briefly and our veterinary team was able to give him a brief well-cub exam.

Watch a video clip of the birth

Keep your eyes on the panda cam and on our website and social media networks for more #cubwatch updates!

Zoo director Dennis Kelly watching the panda cam

Zoo director Dennis Kelly montioring the giant panda cam for the new cub.

September 6

We are still in full panda pregnancy watch and the panda house is now closed to visitors. Mei is especially sensitive to noise, so we keep the panda house as quiet as possible to reduce possible noise-related stress. Virtual Zoo visitors can see Mei Xiang and Tian Tian on the panda cams. Tian Tian will also be in his yard during the day from early morning until about noon.

Mei has been less interested in food lately. She has almost completely stopped eating bamboo; she mostly just shreds it for her nest now. She chooses to not eat much of the produce we give her—like pears and sweet potatoes. These are signs that we are approaching the end of a pregnancy or pseudopregnancy. Over the holiday weekend, keepers started to see her cradle some of her toys and begin body licking. She will most likely spend more time doing those things as we get closer to the end of a pregnancy or pseudopregnancy.

Although Mei has been sleeping a lot more, she continues to diligently build her nest. It is much larger than it was last week. She dragged two very large bamboo stalks into her den. They are so big that they stick out into her indoor habitat, which makes cleaning in the morning more challenging.

Mei Xiang

Mei is rewarded with honey water when she participates in an ultrasound.

Last Tuesday we live-tweeted Mei’s first ultrasound since her behavior started to change. At 8 a.m., when our veterinarians thought Mei would be more willing to participate, she was half-slumbering on the rocks in her habitat and once again we had no luck. But, Mei surprised us about two hours later when she woke up and was ready to participate in an ultrasound.  The veterinarians dashed to the panda house and we live-tweeted the procedure using the hashtag #cubwatch. After about 15 minutes, Mei got up very suddenly and went back to her indoor habitat.

The ultrasound was inconclusive, but it did show that her uterine wall is thickening. We would expect to see that at this stage. The only way we could definitely say that Mei is pregnant before she gives birth is if our veterinarians see a fetus on an ultrasound—which they haven’t. It is not uncommon for panda ultrasounds to be inconclusive and it is very difficult to see a fetus on an ultrasound. We hope that Mei will continue to participate in ultrasounds in the next few weeks, but it is entirely her decision.

On the other side of the panda house, Tian Tian has been continuing his normal summer routine of spending his mornings outside and his afternoons inside. He turned 15 years old on August 27, which he celebrated with a panda-friendly, frozen cake from our department of nutrition.

August 24

Did you catch our pandas on CBS this morning? If you missed them, you can watch the clip to hear about Mei Xiang’s possible pregnancy and how pandas have been winning American hearts since Ling Ling and Hsing Hsing arrived here in 1972.

August 20

Giant panda breeding season just got more interesting! Scientists at the Smithsonian Conservation Biology Institute confirmed late last week that Mei Xiang has entered her secondary hormone phase, which means that they saw a rise in her urinary progesterone. This rise means that she is 40 to 50 days away from giving birth to a cub or the end of a pseudopregnancy. Mei has had five pseduopregnancies since 2007, but we are hopeful that she may have a cub this year.

We have started to see some changes in Mei Xiang’s behavior that support what the hormonal data has told us. She is beginning to build her nest and is dragging bamboo shoots in her den. Our scientists will continue to monitor Mei’s hormones from urine samples over the coming weeks, and the veterinary team regular ultrasounds as long as Mei is willing to participate. Before Mei gave birth to her only cub Tai Shan in 2005 she would not cooperate for ultrasounds in the weeks leading up to his birth. Veterinarians will be looking for any changes in her uterus or signs for a developing fetus. They have not seen any changes yet.

We will know when the end of a pseudogpregnancy or the birth of a cub is imminent based on hormonal data. We will close the area of the panda house that Mei will be in to ensure that she is not disturbed by any noise. Visitors will still be able to see Tian Tian out in his yard and inside the panda house as usual. You will also be able to see Mei on the Zoo’s website via the panda cams. We’ll keep you updated on Mei’s progress over the next several weeks.

Mei Xiang

July 19

Mei Xiang and Tian Tian are still in their summer routines of going outside early in the morning and spending the hottest parts of the day in their indoor exhibits. We will not know if Mei Xiang is pregnant or experiencing a pseudopregnancy (or false pregnancy) for a couple more months. Female giant pandas behave the same way if they are pregnant or not. And unlike humans, we cannot determine if a female panda is pregnant by analyzing her hormones. During a pseudopregnancy a female giant panda’s hormones and behavior are identical to a pregnancy, but she never conceives a cub. What Mei Xiang’s hormones can predict, however, is when we can expect the birth of a cub, or the end of a pseudopregnancy.

When Mei Xiang enters the secondary hormone phase, her progesterone levels will begin to rise quickly. After her hormones start to rise, it will be less than two months until we know if she is pregnant. We will also start to see behaviors that are associated with pregnancy, like cradling toys and body licking. None of Mei’s behaviors or hormone analyses have indicated a rise in her progesterone levels yet this year.

Mei Xiang

We confirmed last Thursday that female red panda, Shama, will not give birth to a cub this year. We believe that she experienced either a pseudopregnancy or the loss of a developing fetus. Fetal loss during early pregnancy is a common occurrence in mammals, but the reasons for this phenomenon are poorly understood. Our scientists and veterinarians speculate that Shama may have experienced the loss of an early-stage fetus that failed to develop normally, and it was absorbed into the lining of the uterus. We expect Shama to return to “normal,” both hormonally and behaviorally, in the coming days, which includes an increase in appetite and activity level.

July 3

Hot, humid summer days mean less active giant pandas. While our giant panda yards are equipped with many cooling features—pools, misters, and cooled grottoes—both Mei Xiang and Tian Tian seem to prefer central air conditioning as their means to beat the Washington summer heat. The indoor panda enclosures are usually kept at a crisp 65 to 70 degrees. Mei Xiang’s enclosures and dens will be kept warmer when she dens up, so that the nest area is at optimal temperature and humidity. It is still too early to tell if Mei is pregnant or not, but we are preparing in case she is.

If you plan your visit early in the morning, you may be able to see Mei and Tian munching bamboo leaves (this time of year, we start to see a decrease in overall bamboo consumption, and both bears are eating leaves almost exclusively, rather than culm or stalk) in their yards for a short while before they take their mid-morning naps. Once awake, both make a hasty retreat back indoors for their second feeding of the day. After that, in true giant panda fashion, both take another nap inside in the late morning and early afternoon hours. Odds are, if you come visit the giant pandas while it's this hot out, you're most likely to find them in thier air-conditioned indoor dens.

giant panda

June 1

It has been quite a month at the David M. Rubenstein Family Giant Panda Habitat and at the Smithsonian Conservation Biology Institute in Front Royal, Virginia! The panda team performed two artificial inseminations (AI) on Mei Xiang on April 29 and 30, after she went into estrus.

Two scientists, Li Desheng and Zhou Yingmin from the China Conservation and Research Center for the Giant Panda in Wolong, flew to Washington, D.C. to help with the procedures. They arrived just in the nick of time! After landing in D.C. on the evening of April 29 they were taken directly to the Zoo where the panda keepers, veterinarians, and scientists were waiting for them. Hormonal data had revealed that after months of waiting, Mei Xiang had finally reached peak estrus and it was the optimal time to do the first AI. Li performed the first of two AIs at 2 a.m. on April 30. The second was at 4 p.m. later that day.

Li returned to China a few days after the procedures, but Zhou went out to SCBI headquarters in Front Royal for a month to work in the endocrinology laboratory. Zhou is an endocrinologist at the China Conservation and Research Center and worked very closely with SCBI endocrinologist Sarah Putman and the endocrinology team during her stay.

Li and other scientists

SCBI’s endocrinologists and Zhou were able to learn a lot from each other. SCBI scientists monitor hormones from animals around the world non-invasively using urine, fecal, and hair samples. For example, at SCBI scientists analyze hair samples using a machine that grinds the hair into a fine powder so they can extract hormones from the hair by shaking the samples in an alcohol solution on a multi-tube vortexer for 24 hours. They then dilute the alcohol solution from each sample and analyze it for hormone concentrations.

Zhou monitors the hormones of the giant pandas at Wolong using urine samples, like the National Zoo does She was really excited to see how we analyze feces and hair because Li wants to do more research on wild giant pandas. It’s very difficult to get a high-quality urine sample from a wild panda. Fecal samples on the other hand, are easier to find in the wild.

Zhou will be teaching the other endocrinologists at Wolong about the new techniques she learned at SCBI. She and her colleagues are busy in China during giant panda breeding season which runs from February to June every year. There, in preparation for breeding season, the endocrinologists monitor the hormones of approximately 20 females from the more than 100 pandas that live at the Conservation and Research Center for the Giant Panda in Wolong. Last year they had 18 cubs as a result of both artificial inseminations and natural breeding. Zhou’s workdays during the breeding season can last from 8:30 a.m. until the middle of the night and can consist of running urine samples multiple times a day for multiple pandas and recommending optimal times for AIs.

Zhou was also interested to share her experiences at Wolong with SCBI endocrinologists because she wanted to see how another lab runs hormone analyses. She wanted to talk about difficult analyses that she and her colleagues have come across and compare how our endocrinology lab would have handled the situation. All the scientists had some really good exchanges and learned a great deal from each other.

Before Zhou returned to China, SCBI scientists gave her a list of all the extremely helpful equipment that the endocrinology lab at SCBI has, as well as electronic copies of the lab’s scientific protocols to take back to Wolong. In the future, it’s hoped that endocrinologists from SCBI will be able to go to Wolong and learn about what they do during giant panda breeding season.

In the meantime since the blitz when Mei Xiang went into estrus on April 29, things at the Panda House have returned to normal. We were not able to collect fresh semen samples from Tian Tian for the artificial inseminations due to the pandas’ vigorous attempts at natural breeding. Luckily, the National Zoo has frozen samples from Tian Tian collected in 2005. The semen collected in 2005 is of high quality and had good sperm motility after it was thawed.

Even though we used semen from 2005, we still wanted to collect a sample from Tian Tian this year. So, on May 16, we anesthetized Tian Tian and collected a semen sample from him. The procedure was quick, and Tian Tian was back on exhibit the same day.

We won’t know if the artificial inseminations were successful for a few months. If Mei Xiang is pregnant she could give birth any time between August and October. Female giant pandas commonly experience pseudopregnancies. That means that their hormone levels and behaviors indicate that they are pregnant even though they are not. We monitor Mei’s hormones over the coming months which will help us determine the end of a pseudopregnancy or an actual pregnancy.

April 30

Giant panda breeding season began this year when Mei Xiang, went into estrus over the weekend of April 28-29, 2012. Li Desheng from the China Conservation and Research Center for the Giant Panda in Wolong, and National Zoo scientists and veterinarians performed an artificial insemination Sunday night after they determined no competent natural breeding had occurred between Mei Xiang and male giant panda, Tian Tian. Li and the National Zoo’s panda team will perform another artificial insemination this evening. The National Zoo’s twitter feed (@NationalZoo) will have live updates of the procedure with the hashtag #pandaAI.

Sunday, April 29, 2012, while under general anesthesia, Mei Xiang was inseminated with thawed semen collected in 2005 from Tian Tian. Scientists determined that semen collected from Tian Tian while he was under general anesthesia Sunday night was not high enough quality to use for an artificial insemination. Zoo staff will continue to monitor Mei Xiang’s hormone levels in the coming months and conduct ultrasounds to see if she is pregnant.


April 2

Spring is in the air at the Panda House—flowers are blooming, bamboo shoots are popping up everywhere (yum!), and there has been a flurry of animal activity. Young red panda Pili recently moved to her new home in California, where she will be paired with a genetically suitable male for breeding in the future. Her sister, Damini, will also be moving to another zoo within the next several weeks, and will also be paired for breeding. Meanwhile, their parents, Shama and Tate, were seen breeding several times in mid-February, and we are hopeful that they will have cubs again this summer.

Although Mei Xiang’s hormones are still at baseline, keepers have noticed some changes in the giant pandas’ behavior indicating that peak estrus may be near. Both pandas are spending a considerable amount of time scent-marking their exhibits, and investigating each other’s scent marks when we move them to a different yard. When we give Tian Tian the opportunity to explore an area where Mei Xiang has recently been, he has been softly bleating, a contact call that changes in intensity as breeding time approaches.

We are conducting mesh introductions daily, giving the pandas an opportunity to interact with each other while being physically separated by a chain link fence. During these intros, we are able to gauge the pandas’ responses to each other, and use that to predict their readiness to breed. In the last several days, we have noted that the bears are interested in each other, but also quite interested in food. When peak estrus occurs, both pandas will be too preoccupied with each other to spend much time eating.

While keepers closely monitor the giant pandas’ behavior, reproductive scientists carefully analyze the hormonal data contained in the daily urine samples and vaginal cytology slides. Taken individually, each of these measures could narrow down the time frame for peak estrus. Together, however, all of these factors can pinpoint with precise accuracy the optimum time for the pandas to breed. Using all of the tools that we have, we hope to help Mei Xiang and Tian Tian produce another cub this year.

Tian Tian medical check-up

March 13

Tian Tian has not been feeling his best for a while. Keepers noted that he was having some soft stool and a decreased appetite. Tian Tian is trained to hold still at the mesh for exams and blood samples, so veterinarians were able to perform a preliminary exam and tests. The results suggested Tian Tian had a urinary tract infection and possible gastrointestinal upset. Tian Tian responded well when given antibiotics and stomach protectants, but his appetite and activity level still weren’t quite back to normal. After consulting with Chinese veterinary colleagues, Zoo curators and veterinarians decided to perform a complete medical workup under anesthesia which included checking his cardiovascular health, bloodwork, radiographs and ultrasounds, and his urinary tract and digestive systems to look for other reasons that Tian Tian might not be feeling 100 percent.

Tian Tian medical check-up

Tian Tian’s checkup went very well. The zoo veterinarians, along with a veterinary cardiologist and a veterinary radiologist, examined Tian Tian thoroughly for any signs of disease. They noticed that Tian has some decreased muscle mass but there was nothing out-of-the-ordinary in the exam or initial lab tests. The vets and pathologists are running more tests on samples they collected. Since Tian Tian’s exam he has gained some weight back and is acting very playful.

In the meantime, Mei Xiang’s hormones remain at baseline. We continue to check her urine for her hormones to rise, which should happen in the next few months. Panda breeding season is typically in the spring and, as the weather attests, we are well on our way.

February 3

Pili and Damini, now sub-adult red pandas, are settled into their enclosure in the giant panda house. They, as well as their parents, Shama and Tate, adjusted well to their move. This is the time that they would have gone their separate ways in the wild. The next big milestones for the red pandas revolve around breeding. For Shama and Tate, breeding will occur in the next month or so. For Pili and Damini, springtime will mean moving to other zoos where they can be paired with suitable male red pandas for breeding in the future.

Meanwhile, for the giant pandas, not much has changed behaviorally since the last update. The behavior watch is now in full swing, but there really hasn’t been a noticeable change in either Tian Tian’s or Mei Xiang’s behavior. Both are continuing to scent-mark and to investigate each other’s scent marks. Keepers are rotating them through different yards on a regular basis to give them maximum opportunities for scent communication.

Keepers are also incorporating some special training into the giant pandas’ daily routine. Tian Tian participates in daily leg-strengthening exercises, which we started to train last breeding season. The purpose of the exercises is to make sure that his hind legs are strong enough to hold a breeding position for an extended period of time. Mei Xiang is called into the training area each morning, so that keepers can look for physical signs (changes in her genital region) that indicate estrus is near. So far, no changes have been noted. In recent years, she’s exhibited early estrus cycles in January. We continue to keep our fingers crossed that she’ll wait until spring this year, which would put her back on a more normal cycle. The norm for the species is for females to go into estrus between March and May.

We are making sure that things are just right in the giant pandas’ environment to set them up for success this breeding season. For example, the lights in the building now go out promptly at 5 p.m. each evening, and remain off until 7 a.m. the next morning, and there is no human activity in or above the panda house during those hours. This way, we can be sure that the bears’ circadian rhythms are not disrupted.

January 13

As the winter progresses, we are becoming more and more optimistic that Mei Xiang is returning to a more species-typical estrus cycle. Giant panda females typically become fertile sometime between March and May, although Mei Xiang came into estrus in January for the past three breeding seasons. We are just now seeing her beginning to scent mark in her exhibit, and we will be watching closely for other tell-tale signs that she’s ready to breed, including bleating, restlessness, and water play.

Tian Tian is showing signs that he’s coming into rut, including patrolling his exhibit and scent marking. As Mei Xiang gets closer to peak estrus, these behaviors will escalate exponentially, and Tian Tian will be exploring every inch of his exhibit and scent marking everything in his path!

A new behavior study will start the week of January 15, and many behavior watch volunteers will be on hand to capture behavioral data about both Mei Xiang and Tian Tian on the web cameras. Web cam watchers may start to notice that the cameras will primarily follow one individual closely each day, alternating daily from one bear to the other – this is for data collection purposes.

The red panda sub-adults (they’re not cubs anymore!) Pili and Damini have stopped nursing and will soon be separated from their parents. Soon they will be moving back into their former indoor exhibit in the giant panda house. This will give their parents Shama and Tate some one-on-one time during red panda breeding season, and will once again give us two red panda exhibits—one outdoors and one indoors. Shama and Tate are most likely to be observed breeding in February, and building up to that visitors are likely to see an increase in playful chasing behavior.

We hope we will soon be hearing the pitter-patter of both giant panda and red panda cub paws in the summertime!

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