panda bai yun


Beautiful Bai Yun

This is Bai Yun in 2005 and shows the bamboo leaves.

This is Bai Yun in 2005 with some leafy bamboo.

I sometimes spend way too much time in front of my computer! This morning, I decided to check on my panda friends in person, rather than on Panda Cam, something I don’t do often enough. The Zoo was just opening for the day, so I was one of the first people to enter the panda viewing area, and it was cool and peaceful.

Mr. Wu was high in the tree–I think guests riding our Skyfari aerial tram could see him better than I could! But mama Bai Yun was right up front, sitting on her haunches and contentedly eating breakfast. It struck me hard how gorgeous she is! And how large she is! She had a huge pile of bamboo “tips” to her right. By tips, I mean long, thin branches with rich-green leaves. She would grab a clump of the branches and, with one sweeping motion of her mouth, peel the leaves right off so that they stuck out of the side of her mouth briefly before she swallowed them. In any other creature, it would have looked comical, but there is a grace and confidence about Bai Yun that inspires admiration and awe.

I stood watching her as she calmly ate in this fashion. She paused and looked me right in the eye (be still, my heart!), and then she continued her meal. I finally tore myself away from her to see what Yun Zi was doing in the enclosure next door. He was on top of the artificial den, flat on his back and sound asleep. But that’s okay: Bai Yun and I shared a beautiful summer morning. What a great way to start the day. I may have to do this more often!

Debbie Andreen is an associate editor for San Diego Zoo Global. Read her previous post, New Koala Exhibit Now Open.


Perfectly Panda

Bai Yun is taking good care of her cub and herself.

Bai Yun and her cub are doing well, and their relationship has been evolving in predictable panda ways. As the cub grows, he can get bigger bellyfuls of milk with each feeding, which is followed by longer periods of sound rest. This means Bai Yun has more and more free time. What has she been doing with that free time?

Bai Yun continues to increase her time spent feeding outside of the den. She is taking in large quantities of leaf eater biscuits and produce. She is feeding on increasingly more bamboo as well, although she is not quite back to pre-pregnancy consumption levels. Bamboo feeding is a process, and it takes time, so as her intake continues to increase, we can expect her to be out of the den for longer periods. As the cub grows, the demands of lactation will also increase, so she will need every calorie she can get her paws on to ensure an abundant milk supply. Luckily, our keepers stand ready to assist.

Sometimes Bai Yun comes out of the den to rest on her own. She can most commonly be found only a few feet away from the den door, in her bedroom. This allows her a little extra space, some cub-free time, and some fresh air. The air in the bedroom is also a little cooler than the den, as our AC unit feeds directly to that room. Perhaps this has been a factor for her during some of our recent heat waves.

She has been utilizing the garden room, too. Those long-time viewers of Panda Cam will recall her favorite platform in that area. She’s taken several recent naps there. Sometimes Bai Yun takes the cub out with her. She’ll head out to the bedroom to feed or rest and plunk her youngster down beside her. Often the cub is asleep during these forays.

Occasionally, he is awake and squirming on the floor next to his mother. Once, Bai Yun even placed the cub on the scale in the bedroom, and keepers were able to use that opportunity to record a weight for him (thank you, Bai Yun!). So far, she has only introduced the cub to the bedroom; the garden room remains a destination for some future date of Bai Yun’s choosing.

Sometimes, Bai Yun can be observed wrestling with her offspring. She’ll turn the youngster around in her paws, nibbling at him playfully. At this stage, the cub is not able to return the play with much vigor, but watch closely—that will change soon. We’ve already seen the cub mouthing his mother’s paws, gnawing on digits. One element missing from your play-bout experience is the audio that staff can hear. Throughout most of Bai Yun’s play sessions, the cub is silent. Obviously, Bai Yun’s play activity is not bothersome to him. It may even be good for him in some way. Certainly it seems important for Bai Yun in some way we don’t yet understand.

None of what we have seen with Bai Yun since the birth of this cub is unusual or unexpected. She’s been the excellent mother we anticipated she would be. The cub continues to grow and develop in a way that pleases us. Mother and cub appear perfectly panda, both physically and behaviorally.

And we wouldn’t have it any other way.

Suzanne Hall is a senior research technician for the San Diego Zoo Institute for Conservation Research. Read her previous post, Pandas: Me Time.


Night Watch: Mission Accepted

Can you start to see the cub’s panda colors?

Being a relief mammal keeper can be difficult. You need to be trained to work in multiple areas, remember all the safety protocols, and know how to identify individual animals, as well as build a relationship with those animals so that you work well with them and have the ability to notice when something is out of the ordinary. However, being a relief keeper also has benefits. You have the opportunity to work with a variety of animals in different areas of the San Diego Zoo, assist with training new behaviors or maintain existing ones, and be there to help wherever and whenever the department needs you. When I found out I was needed to help monitor our pregnant panda, Bai Yun, for signs of labor and later to monitor Mom and cub’s well-being, I accepted the mission. After all, it is my job! Once I found out that mission would take place overnight, from 7:30 p.m. to 4 a.m., by myself for two weeks, my mind began racing. Would I be able to stay up all night? If something went wrong, how quickly could someone back me up? Would I be able to stay up all night? How well can I work all the camera equipment?

All of those anxious feelings quickly turned to excitement about what I was going to be a part of. How many people can say that their job required them to spend 80 hours monitoring a mother panda and her brand new cub?! What an amazing 80 hours it has been! Sure, much of the time was spent watching Bai Yun sleep in the den, but all of those hours were worth it when I was fortunate to be the only keeper on duty the first time Bai Yun left the den, giving me and anyone else watching Panda Cam the very first look at the new cub! I will never forget that moment: Monday, July 30, at 9:10 p.m.

I noticed Bai Yun re-positioning a lot, then all of a sudden she stood up and walked out of the den, leaving the cub flailing about and squawking. I was so excited but had to do my best to contain myself in order to do my job and gather as much information as possible. First, note the time; second, work the camera to get a good look at the cub; and finally, try to figure out where Bai Yun left, why, and what time she returned. Somehow I was able to accomplish all that while being in absolute amazement of what I was witnessing. I had been hearing the tiny cub off and on, but now I was able to see it and, more importantly, see that it was doing well. Of course, Bai Yun has been a mother five times before, but I wasn’t there for those cubs; this was my first time seeing her with a newborn, watching her enormous paws and mouth so carefully embrace this 4-ounce being, and it was unforgettable.

Since that unveiling of her cub, I have had several more opportunities to see it, as well as witness her gentle care, yet every time feels like the first. While it has been a great couple of weeks sitting in front of monitors, logging hours of observations, and being part of a new life, it is time to get back to my regular schedule of more physically demanding work wherever the department needs me. I get to work in the sun again with all the other amazing animals I have missed. Being a relief keeper is a tough job, but as they say, somebody has to do it. I’m happy that somebody is me!

Jennifer Chapman is a keeper at the San Diego Zoo.


Panda Bai Yun: Still Waiting

Well, Bai Yun?

Over the years, we have often used words like “textbook” and “clockwork” to describe giant panda Bai Yun’s reproductive behavior. This year, however, has been different, and Bai Yun is reminding the San Diego Zoo’s Panda Team that we still have a lot to learn about pandas!

While much of what we’re observing of Bai Yun’s behavior and hormone levels is consistent with past pregnancies, we are still unsure of her status. As a result, while we think it is safe to say that we are all feeling a bit anxious, we are continuing our pregnancy monitoring efforts. Veterinarians are still conducting regular ultrasounds, and researchers and animal care staff are still doing all that needs to be done to perform thermal imaging and to monitor hormone levels and behavior.

The average gestation period for a panda is about 135 days. Interestingly, one of the longest gestation periods we have a record for is 184 days, and this record is held by Bai Yun’s mother, Dong Dong! We’re hopeful that we might still have a pregnancy but are watching with a scientific eye to see what new discoveries we might be able to make about the reproduction of giant pandas.


Panda Pregnancy: Detection

After a successful breeding season in which we are fortunate enough to realize one or more breeding sessions between Bai Yun and Gao Gao, we then shift into “wait and see” mode. During this time we wait out the period of embryonic diapause (see post, Panda Pregnancy: Embryonic Diapause).  Then, once progestins begin to rise, and Bai Yun’s behavior begins to change, we start to look for clues that help us determine if our female is pseudopregnant or will, in fact, give birth (see post, Panda Pregnancy: Pseudopregnancy).

In the past, there was only one tried-and-true method to distinguish between the two: witness a birth. If a female had a cub (or two), then obviously she was not pseudopregnant. So it was that staff at a panda facility would spend quite a bit of time observing a female, watching for signs of labor to confirm that a cub was imminent.

I recall sitting in a darkened observation area in the middle of the night for months on end back in 1998. We had artificially inseminated Bai Yun earlier in the year, and we had no idea if she was pregnant. We were also uncertain about the timing of any potential birth. For six months staff rotated through the area, and there was always someone whose job it was to watch Bai Yun. It was a 24-hour-a-day assignment. Alas, you know that Hua Mei was our first-born cub (in 1999), so I don’t have to tell you how those intense six months ended.

Things have improved quite a bit since then. The biggest change over the last decade has been our ability to visualize a panda fetus via ultrasound. Once our veterinarians are able to see a heartbeat in utero, it becomes quite clear that we are not witnessing a pseudopregnancy: the female obviously conceived, implanted, and began to grow a new little panda. Hua Mei provided our very first in-utero cub photo just three days before she was born. That was a very exciting day, and it’s one I will always remember very clearly! Where were you when the first panda fetal image was obtained?

Since then, our vets have been able to get visuals of our fetal cubs with great regularity, charting their development in utero much as an OB-GYN might do for a human patient. But there has been another exciting development in panda pregnancy detection: the advent of a ceruloplasmin test.

Ceruloplasmin is a protein that recently has been shown to be a positive indicator of pregnancy in pandas. And I mean recent: research on this detection method has been published only in the last few weeks, it’s that new! There are many promising things about this new test, but the most exciting is that it provides us with a way to distinguish pregnant from pseudopregnant bears. It may also help us make that distinction early on in a pregnancy. In the future, it should become a powerful tool for panda facilities to utilize.

So where are we with Bai Yun in 2011? We aren’t able to run her ceruloplasmin yet, as the test is so new there are some logistical issues to deal with in getting the results in a timely fashion. So we can’t tell you what is happening on that front. Our vets have been doing ultrasounds with Bai Yun for some time, and, to date, they have yet to confirm a heartbeat in utero. This means we are still waiting.

And I know you are, too. Until we have definitive information either way that Bai Yun will—or will not—be delivering a cub this year, we will all just have to get used to waiting. Just like the old days!

Suzanne Hall is a senior research technician for the San Diego Zoo Institute for Conservation Research.


Panda Pregnancy: Pseudopregnancy

Why is pregnancy in pandas such a complex affair? On Friday, we reviewed embryonic diapause as a factor in adjusting the length of panda pregnancies (see post Panda Pregnancy: Embryonic Diapause), and today I’ll describe another interesting aspect of their reproductive strategy: pseudopregnancy.

First, a definition: what is pseudopregnancy? Sometimes known as a “false pregnancy,” a pseudopregnancy occurs when a female exhibits the signs and symptoms of pregnancy when in fact she is not experiencing one. Like embryonic diapause, pseudopregnancy is not a phenomenon limited to pandas; it has been observed in mice, dogs, and even humans.

In pandas, the signs and symptoms of pregnancy that also occur in a pseudopregnancy include a decrease in appetite, a decrease in activity level, and even physiological changes to the genitalia. The onset of these changes in a pregnant female follow the rise in progesterone noted after the period of embryonic diapause, when the blastocyst implants in the uterus. But here is where it gets tricky: pseudopregnant females also experience a rise in progestins. It is what is driving their behavioral changes, too.

In many animals, the way to detect pregnancy is to look for the presence of progestin byproducts in the urine, feces, or blood. In a panda, if you find progestins in the urine of a female you can only say definitively that she is either pregnant or pseudopregnant. So far, we haven’t been able to identify a way with progestins to tell for sure if she is gestating a fetus.

Over the years, panda researchers have puzzled over this. What is really going on here? Is it possible that pseudopregnant females were actually bears that had, indeed, gotten pregnant but miscarried before the birth? That is certainly possible, and Bai Yun has shown us via ultrasound that she has three times carried twins only to give birth to a singleton. Clearly there is fetal death occurring in utero from time to time. It is entirely possible that many “false” pregnancies would retrospectively be classified this way, had ultrasound technology been more available in the past.

However, it is also true that in some cases, pseudopregnancy has been noted in females who had not even had the chance to breed. Thus, for those females, there was no possibility of a pregnancy (or miscarriage), and they went through the behavioral motions anyway.

Why would a female panda experience the signs and symptoms of pregnancy even if she didn’t give birth? We aren’t entirely certain, but here is one theory: because it doesn’t cost them much to do so. From an energetic perspective, it doesn’t take much effort to slow down and allow your body to become physiologically primed to gestate a panda fetus. Cubs only grow for about 50 days, which doesn’t require a long-term commitment. And if you are a panda, which only mates once every two to three years while raising a single cub in between, it is important to have that pregnancy “take.” If you miss a year, it’s a big loss to your lifetime reproductive output. When the typical lifespan of a wild panda is no more than 20 years, and a female isn’t fertile until at least 5 years of age, she can only rear about a half dozen cubs in her lifetime. Losing one has a big impact on her overall reproductive success. In the end, it could be as simple as a little cost-benefit math equation: pandas can’t afford to lose the chance to reproduce, and it doesn’t cost them much to be prepared.

Embryonic diapause makes it difficult to assess when we should expect a birth in the time shortly after breeding. Pseudopregnancy insures that we must interpret our progesterone and behavioral indicators with caution. How, then, do we actually confirm a pregnancy in pandas? I’m sure you have some idea, but there is also some new and exciting research on that front. That will be the topic for my next entry. Stay tuned!

Suzanne Hall is a senior research technician for the San Diego Zoo’s Institute for Conservation Research.


Panda Bai Yun: Is She?


The big question around here has been “Is Bai Yun pregnant?” We are all on pins and needles wondering the same question. Our breeding sessions took place on April 15 and 16, and right now it is way too early to confirm or deny a pregnancy!

The San Diego Zoo’s Panda Team is performing weekly thermal imaging scans and ultrasound procedures on her; these sessions provide real data that will allow us to understand how pregnancy unfolds in the panda from different perspectives (see post Panda: Thermal Images Revealed).  Sometimes, animals need help remembering a behavior that they may have learned a long time ago. For Bai Yun, she only has to cooperate for ultrasounds every two years when she may be pregnant. These weekly thermal scans also help to get her back into the “swing of things.” Bai Yun has been trained on more behaviors than any of our other pandas, and as long as we practice them with her on a regular basis, she will retain that memory of what she is to do.

We will keep you updated on how things are progressing for Bai Yun, and, of course, please come see her at the Zoo. She is in our North Exhibit (formerly known as the Classroom Exhibit) from 9:30 a.m. to 2:30 p.m. daily.

Anastasia Horning is a panda narrator and relief keeper at the San Diego Zoo. Read her previous post, Scaly Animal Ambassadors.


Yun Zi’s Spring Break

Yun Zi

Yun Zi is currently enjoying a change of scenery, where the grass is greener and the trees are in bloom. The 111-pound (50kg), 3-foot-tall (when standing) young adult is trying out new climbing challenges in one of the exhibits that is visible to the public (and one that has a better camera for all his fans at home!), the one he first saw as a young cub. He will temporarily have access to this space, depending on Bai Yun’s breeding time. Please be patient with our Yun Zi as he will have a slow acclimation to this exhibit.  He will still have access to an off-exhibit area while he gets used to the new exhibit and dealing with his paparazzi.

Yun Zi is also moving forward with his training for the hearing study.  He is currently learning how to be patient and to sit with his chin on a small shelf.  The next step will be to target (touch his nose) to a red circle when he hears a sound. This study will help our researchers determine his range of hearing. He is an extremely intelligent panda, and he challenges my patience as his keeper and trainer. Yun Zi takes his training extremely seriously and is always ready for a training session.  I am excited that we are working toward including him in the hearing study.  I am extremely proud of him and excited to see him excel like his sisters Su Lin and Zhen Zhen.

Jennifer Becerra is a senior keeper at the San Diego Zoo.


Sprucing Up for the Holidays

Bai Yun in 2001

As you may have noticed, the background is different on Panda Cam. Bai Yun and Yun Zi have been temporarily moved to the north exhibit (formerly called the “classroom”), and Gao to his back area for a few days to allow the keepers and horticulturists to make some magic in the main viewing areas. After all, November through mid-January is a busy time here at the Zoo, with vacationers, holiday celebrators, family visitors, and football fans in Southern California for the many Bowl games. Everyone at the Zoo wants their place to look its best for guests, and before the holiday rush is a great time for sprucing things up.

While I haven’t seen the plan, word is it involves some new trees, sod, and replacement of decaying climbing structures. Zoo “furniture” is often just trunks and branches recycled from culled or dead trees, and like all wood can only withstand the effects of weather and natural decay processes for so long. While we can appreciate the natural forces at work here, we, of course, want our pandas to be safe and their climbing structures sturdy enough for an ever-growing, always climbing young cub

The pandas made the move with their usual aplomb, Gao Gao settling right back into “his” area and Bai into “hers,” with Yunnie along for the trip. The transitions offer the pandas their own kind of environmental enrichment: a change of scene and new olfactory areas to explore. The scent-mark residue and other smells left by Zhen Zhen and Su Lin can remain for many months, and pandas do a lot of olfactory exploration and scent marking when entering a “new” area. It seems so appropriate to see Bai back in that area; it was the space where she was first introduced 14 years ago for her arrival and quarantine. (Since it was a new area and had never been used by another animal, it was perfectly safe to quarantine her there, rather than at the Zoo’s hospital facility. That would have necessitated another move, and we didn’t know then how adaptable she would be.) A young adult at the time, she still had a playful edge and the will to climb high, often napping draped over the branches of a pine tree now long gone. This exhibit has remained the place where she appears most comfortable, no matter how long she’s been away in other areas. How much has happened in her life during these past years, and now here she is with her fifth cub, back where she started, for at least a little while.

While the exhibit renovations sound complicated, I am in awe of our horticulture staff and their ability to swoop (metaphorically) into an area and transform it to “done” in a matter of days. This being said, it shouldn’t be long before the pandas are back in their viewing area with a new environment to explore, filled with new scents and new possibilities for exploration. Who knew that renovations came with such added bonuses?

Ellie Rosenbaum is a panda narrator at the San Diego Zoo. Read her previous post, Let Her Eat Cake—Whenever!


October Pandas

October is Kids Free Days at the San Diego Zoo (and San Diego Zoo Safari Park Park), and we are getting quite a large crowd of children eager to see and learn about our smallest panda, Yun Zi. This has always been one of my favorite times of the year, partly because kids ask some of those questions most of us adults just never think to ask! This time of year presents opportunities for educating the kids on what’s going on at the San Diego Zoo, and it is also a time where we see a change in many of our animals’ behaviors.

As the weather cools, we see that our animals have a change in appetite and activity level. Animals that spent their summer days relaxing are starting to play a little more. Yun Zi is a perfect example of this: last week he chased his mother around the enclosure for about an hour, trying to play while she just wanted a nap. Bai Yun would grab the youngster and push him away, but as soon as he got his balance again, he was after her.

But also with this weather we see our little man sleeping in quite a bit more! For those of you who have followed the pandas, you know that when cubs go through different stages of development they also change their habits. Yun Zi is beginning to eat more and more bamboo, but he still likes to have that time with Mom to nurse. There really isn’t an exact amount of time that he nurses a day, and of course there’s really no schedule to it, but it’s always nice to see Bai Yun with her cub every now and then, having that special time with her.

I have seen Bai Yun eating for longer periods of time in one sitting. Saturday, she ate for a good two hours straight, partially because the cub wasn’t on the ground to bug her. Females will often drop some weight when they are nursing, and for Bai Yun, this is something we expect to see. As we approach winter (granted it’s a San Diego winter), and after the cub is weaned, we will see her weight begin to rise at a steady rate.

Gao Gao is doing a wonderful job at entertaining our crowds. Being in the spotlight again has not fazed him one bit, and he is happy to sit and eat right in front of his admirers as they enter the viewing area. So many times when Bai Yun and Yun Zi are sleeping, I have guests tell me how great it is to just watch Gao Gao, since he’s right up in front. We are certainly glad to have him back on exhibit, showing what giant pandas do so well: EAT!

Come see us soon, if you can, and I hope everyone has a wonderful autumn!

Anastasia Horning is a panda narrator at the San Diego Zoo. Read her previous post, Hello, Handsome Gao Gao!