Bai Yun


Summer Pandas


Xiao Liwu got a swing for his birthday—the perfect gift for this active young bear!

The end of the Zoo’s longer summer hours is in sight, and our animals are getting hit with another big heat wave. This year has been a more mild summer as a whole, but we have had some small sprints of heat. Many of you, visiting or watching, have noticed that Gao Gao has spent many of his summer days in the air conditioning. While this has been frustrating for our guests visiting, please know how much we appreciate your cooperation while we get Gao Gao bear through summer.

While Gao Gao has been relaxing most of the day, Xiao Liwu has been quite a character to watch! Throughout the day we have observed him having random energy bursts, and showing off to our guests. Remember this is normal for a panda as they go through their first hormone shift at three years of age! For those of us that have been watching him since birth, up close, it’s great to see him really exhibit these bear behaviors.

I have had the amazing opportunity to watch five of our panda cubs go through their first hormone shift, and it NEVER gets old. Right now I can honestly say that there is no perfect time to come visit the pandas for good activity levels; there are mornings where Mr. Wu is entirely on FOOD mode, there’s SLEEP mode, and then there’s DEMO mode! Right now, he has been eating for several hours a day, no specific time, and there is almost always a time where he is running, rolling around, and jumping on stuff in his enclosure.

Bai Yun is still in our behind-the scenes-area. As many of you know, our vets have come to the conclusion that she is not pregnant. While we are of course disappointed, we are glad that she is healthy and doing well. Our keepers will be working with her on a daily basis, and getting her out of her den and outside into her garden room. This is a process in itself. Making sure she’s comfortable is their number one priority and they are easing her back into her normal routine.

So thank you again for your understanding and helping us keep our animals comfortable—remember that in the heat of the day none of our bears are really going to want to be up and about! And this coming week, drink lots of water while you’re visiting us at the Zoo!


No Pregnancy for Panda at San Diego Zoo

PrintSan Diego Zoo Global scientists have confirmed that the female giant panda, Bai Yun, is not pregnant.

During a naturally-occurring estrous cycle in March 2015, Zoo staff performed an artificial insemination procedure following unsuccessful breeding sessions with male, Gao Gao. Since the artificial insemination procedure, veterinarians, animal care personnel from the San Diego Zoo along with scientists and researchers at the San Diego Zoo Institute for Conservation Research have been tracking her hormone levels and watching for behavioral signs of pregnancy. In addition to the hormone tracking, ultrasounds and thermal imaging were conducted to check for any fetal development. All methods used for monitoring for a possible pregnancy are providing conclusive negative results.

Female giant pandas experience estrus just once a year and it only lasts for 48 to 72 hours. If Bai Yun had been pregnant, she would have been one of the oldest giant pandas to give birth. Her mother currently holds that record.


Ahoy! Let’s Celebrate Xiao Liwu’s Birthday!


Flashback to Xiao Liwu’s first photo at about a month old. Oh, that face!

Xiao Liwu’s 3rd Birthday is July 29th  but we are going to have his big party on August 1st for him, beginning at 9 a.m. (US Pacific Daylight Time), so mark your calendars and set your alarm!  We are looking forward to seeing what his ice cake (crafted by our creative Forage Team) looks like this year. We as a team always enjoy this little surprise and the only hint we have had is that it is orange. (You can read about how an ice cake is made here.)

“X marks the spot” when the Forage Team delivers the cake at 8:45 a.m., while we keepers put out all his enrichment.  The birthday boy will be able to come aboard his exhibit at 9:15 a.m., right after the Zoo opens so all of his crew and friends can be there to watch him enjoy his cake and “presents.”  Mr. Wu  has commandeered the cave exhibit, so his fans will have a bigger space to view the celebration.  This is also the better exhibit for Panda Cam viewing so all the Panda Fans that cannot be there in person can celebrate with us, too!

Mr. Wu still is our “Little Gift” and amazes us everyday. He is now 149.6 pounds (68 kilograms) and is still small but mighty. He has been going through the destructive phase, testing the limits of every climbing branch and log in his exhibit.  So be ready for the fact that there may be times that he falls or gets a new scrape, just like any young boy would.  He has many playful bouts of running around and enjoying his enrichment, but he still remains patient during his training sessions.  We have taken a little break with his blood pressure readings, as Bai Yun has been having full access to the training crate.

As keepers we look forward to this time to give all our pandas extra enrichment in celebration of this milestone—another year closer to being an adult (which usually is around five years of age).  If you are able to come to the celebration in person, please also stop over at our Volunteer table to learn about giant pandas and look at our special artifacts.

We know one day that Mr. Wu will add to the genetic diversity of future giant pandas and maybe even one day his future cubs will be candidates for release into the wild. In this way and so many others he is a “Little Gift” that keeps on giving!

Jennifer Becerra is a senior keeper at the San Diego Zoo. Read her previous post, Happy Anniversary, Gao Gao.


San Diego Zoo Veterinarians Conduct Ultrasound on Giant Panda

PrintSan Diego Zoo veterinarians and panda keepers gathered early this morning behind the giant panda exhibit for an ultrasound examination of 24-year-old female Bai Yun. Veterinarians used ultrasound technology to look for signs of fetal development in Bai Yun’s reproductive track, including the uterine horns, and signs of an embryonic sack. The staff is monitoring the mother of six pandas for a possible pregnancy, following an artificial insemination procedure that took place four months ago.

The 240-pound panda was lying still while being fed honey-water from a squeeze bottle during the examination, which lasted about 20 minutes.

“As I’m feeding Bai Yun during the exam, I look for different things,” said Kathy Hawk, senior keeper at the San Diego Zoo. “If her eyes look soft, it says to me that she is content with what I’m feeding her and comfortable with the veterinarian during the procedure. This morning Bai Yun made it clear to me that red apples were out and that honey-water is in – she liked the honey-water.”

Animal care staff will continue to monitor Bai Yun with regular ultrasounds, thermal imaging, and hormone testing over the next few weeks. San Diego Zoo staff members are keeping the area around Bai Yun’s den quiet, and only essential staff is being allowed in the area.

Following natural breeding sessions between Bai Yun and Gao Gao in March 2015, which didn’t appear to animal care staff to be successful, it was decided, in collaboration with our Chinese conservation partners, to conduct artificial insemination with sperm stored in the Frozen Zoo®. The sperm used was from giant panda Shi Shi, who was the first breeding partner for Bai Yun. His sperm was used during an artificial insemination procedure with Bai Yun in 1999. That procedure produced the first cub born at the San Diego Zoo – and the first in the United States – a female named Hua Mei. In 2003, Shi Shi returned to China for his retirement years, and he died in 2008. The San Diego Zoo has a record of success, with six cubs being born in San Diego since 1999.

A panda’s fertilized egg remains suspended until a trigger in the environment indicates it is time to implant. The trigger is still unknown to scientists. Giant pandas routinely delay the implantation of the fetus as long as four months. After implantation, the fertilized egg begins to develop. Impending birth is predicted on the basis of behavioral, hormonal, and anatomical changes documented by scientists at the San Diego Zoo’s Institute for Conservation Research.

If a cub is born, Bai Yun will be the oldest giant panda known to give birth to a cub. The mother and the cub would be expected to remain in the den for four to five months before returning to a public exhibit.

Newborn giant panda cubs are born without sight and weigh an average of 4 ounces (112 grams) when they are born. They are pink with thin white fur that will gray before the trademark black-and-white markings develop, within the first months. The sex of the cub would not be known until animal care staff members examine the cub, which would not be expected to happen until the cub approached two months old.

Bringing species back from the brink of extinction is the goal of San Diego Zoo Global. As a leader in conservation, the work of San Diego Zoo Global includes on-site wildlife conservation efforts (representing both plants and animals) at the San Diego Zoo, the San Diego Zoo Safari Park, and San Diego Zoo Institute for Conservation Research, as well as international field programs on six continents. The work of these entities is inspiring children through the San Diego Zoo Kids network, reaching out through the Internet and in children’s hospitals nationwide. The work of San Diego Zoo Global is made possible by the San Diego Zoo Global Wildlife Conservancy and is supported in part by the Foundation of San Diego Zoo Global.



Good Weather, Good Food

Gao Gao has been in fine form lately, climbing trees and scent marking.

Gao Gao has been in fine form lately, climbing trees and generally giving keepers quite a show!

Lately, as I have been narrating down at the panda enclosure, I’m seeing the bears relax, sit back, and enjoy the food. As many of you know, we feed several different types of bamboo to our bears, and in recent days they have really been enjoying themselves! Bai Yun will often eat for a few hours at a time, and even Mr Xiao Liwu has been doing very well ripping the bamboo apart. And it seems while they’ve been relaxing, panda fans have been thinking; we have been getting a lot of questions about breeding the bears this year.

As of last week we have not seen any change in Bai Yun hormone reading or physical state. However, on a fairly regular basis we have observed her scent marking repeatedly around the enclosure, and even engaging in “water play”, a behavior we typically see when there is a hormone shift. As it is still early for her regular breeding season, we expect to continue watching her closely over the next couple of months and will monitor any progression towards an estrus. She is extremely healthy; one of the benefits about being captive born is a fantastic health package!

Gao Gao has been eating extremely well in his off-exhibit digs, and has been climbing up and down the trees giving our keepers quite a show in the back area. Engaging in handstand scent markings is always fun to see, and having him this active is a nice change of pace.

Now, please remember: even though he is quite vigorous right now and showing a lot of enthusiasm, we cannot put him in with Bai Yun unless we have positive evidence showing her in estrus. Our vet staff will ultimately have the final word on breeding the bears, and rest assured they always keep the animals’ best interests in mind and at heart.

Little Mr. Wu has also been showing lots of energy and spunk. On a daily basis we see him run around the enclosure, playing with enrichment that keepers have put out for him. Our guests have enjoyed watching him and his moves, and it has been great to show our guests what these bears are capable of. Over the next few months we may see more activity and more growth spurts!

Come see us soon!


Pandas in Winter

Cold temperatures? Extra bamboo? Works for Bai Yun!

Cold temperatures? Extra bamboo? Works for Bai Yun!

For the first time in a long time, our pandas are actually getting some truly winter weather. We’ve had some rain recently, and temperatures in the first week of the new year were really low for our region. And the geography of the Zoo means some parts of the grounds feel the chill more than others; Panda Canyon is usually 10 to 15 degrees cooler than the main entrance (where temperatures were in the mid-50s). Although the staff is feeling a bit chilly, the bears are loving this weather!

Giant pandas have a very thick, dense fur coat and like most bears they will try to gain as much weight as possible for winter, but they do not go into torpor (commonly called hibernation). Unlike their counterparts in China and zoos in colder parts of the world, our pandas don’t usually have much of a winter to deal with, but rest assured they are all doing just fine with this cold snap!

We always offer more food than what the bears will actually eat. This allows them to have variety in their diet but also giving them access to extra calories should they so desire. Our pandas do not weigh as much as other pandas that go through more severe winters, because they don’t need the extra insulating fat layer here in San Diego.

As someone who has worked both directly and indirectly (as a Panda Narrator) with the bears, I can honestly say that I love watching them in cold weather. You get to see them eat more and the younger pandas get a little more hop to their step. Yun Zi was one of my favorites to watch in winter. He was always an active fellow, but when it was cold or raining he’d roll in the mud and really tear his exhibit apart. Not always fun to clean up after, but a blast to observe!

No matter what the weather, Bai Yun tends to do her normal thing—eat till she’s tired, then take a nap. I often joke that she’s been here in San Diego for so long nothing much can surprise her anymore. Gao Gao will remain off exhibit in the North Exhibit, with regular access to his bedroom. The perk about having the back area to himself is that he can pretty much run his day however he wants. Inside or out he’s got full reign of the area in the back. Mr. Wu will be on exhibit, and I’m looking forward to watching him and see how he reacts to this cold snap. I know it’s not cold compared to where a lot of you are from, but for these bears, and us, it’s definitely a change!

Happy New Year and hope you are all well! Come see us soon in 2015!

Anastasia Horning is a panda narrator and keeper at the San Diego Zoo. Read her previous post, Dealing with Noise in Panda Canyon.


Dealing with Noise in Panda Canyon

Bai Yun is a pro at dealing with activity around Panda Trek.

New noises catch Bai Yun’s attention, then it’s back to “business as usual.”

As many of you have seen on Panda Cam and in person, young Mr. Wu is off exhibit at times and only Bai Yun is present. Rest assured there is nothing wrong with him and he is perfectly fine. Our Zoo is coming up on its 100th birthday soon, so we are improving areas and updating where we can. With that comes a certain amount of noise that we really cannot get away from, so we closely monitor our animals for any signs of stress.

Xiao Liwu, being younger and not as experienced with new sounds, is more likely to react to the construction noise. Bai Yun is typically a pro at changes and has been managing extremely well. One of the benefits of having a panda narrator keeping an eye on the bears is that the narrator is familiar with each animal and can tell the Panda Team when there is a change in behavior. Our Web Team will always do its best to notify you when there may be a change in who is out for viewing, but the fact of the matter is that things can change quickly here, and we often need to make judgment calls quickly, too.

When the bears are off exhibit, they still have an outside yard they can go into if they so choose. Both of the north exhibits are close to bedrooms and, if needed, the keepers can give the pandas access to the bedrooms. The bedrooms offer a dry and cozy area for the pandas. Keepers often fill a giant tub full of hay or shavings for the bears to rest in, and there is a garden room for them to go into as well. Having a building between them and the extra noise often makes a huge difference in a panda’s comfort level and helps diminish any stress behavior.

Bai Yun is an expert at dealing with noise. When we were building the rest of Panda Trek, she was still able to be out in the main viewing area, right next to the noise. There were, of course, days where we noticed that she was a little annoyed with the activity level and so gave her access to her bedroom. There are several cameras in the area, and the panda narrator and guest ambassador all keep an eye—and ear—out for her to make sure that she is comfortable. In many situations, just giving her 10 to 15 minutes in her bedroom to get a little break will often set her right. In addition, we always do our best to make sure that she has extra bamboo that she is fond of and to try and keep her busy with enrichment.

Come see us soon, and please know that we are always thinking of how to make this an easy time for our animals!
Anastasia Horning is a panda narrator and keeper at the San Diego Zoo. Read her previous post, Talkin’ about Takins.



First Snow Day for Panda Cub!

Yun Zi was 2 when he saw his first snow.Tuesday, March 19, starting at 7 a.m., we are preparing for snow in the panda exhibits. We are very excited and thankful to all the panda fans who donated money to give this wonderful enrichment to our giant pandas. I am sure we will see you at 9 a.m. sharp in person or starting around 8 a.m. on the Panda Cam!

It’s a bit of a process to actually make snow and put it in the exhibits. We have a truck that comes in and is specially designed to turn large ice blocks into snow. There are large hoses that we can hold and deliver (spray) snow into the entire panda exhibit. Snow will be blown into Bai Yun and Xiao Liwu’s north exhibit and into Gao Gao’s exhibit in the main viewing area.

Sadly, Yun Zi’s new tree will not be done in time (due to a couple of days of rain), and he will stay housed next to Bai Yun and Mr. Wu for a few more days. But don’t fret! Yun Zi will be getting snow, too, and we will make sure he has a mound of it to play in.

We are all excited to see how brave Mr. Wu is and what his first reaction will be when he puts his paws in it. Hopefully, it will be a wonderful play day for both bears and guests!

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

Here’s Zhen Zhen when she saw her first snow:


My Moment With Our Black and White Celebrity!

It finally happened, I was able to help with a cub exam! I have been waiting for this moment since my first look at the cub during my night watch shift. As we began setting up for the exam, my excitement quickly turned to nervousness, and my mind raced. There were cameras, researchers, veterinarians, nutritionists, fellow keepers and supervisors, and it was up to me to keep our celebrity calm!  

Then it was time: Bai Yun shifted out to her breakfast, and she was calm. Now was my chance to pick up the cub, weigh him, and bring him out for his exam. I picked him up and placed him on his blanket, along with several bamboo leaves that I had to clean off of him so he would be camera ready. I gently placed him on the scale; he weighed 7.26 pounds (3.29 kilograms)! Now out to the cameras, the veterinarian, and the nutritionist for his exam. He did so well! He made a few vocalizations here and there, and he is getting much more mobile–he even crawled–but the veterinarian and nutritionist were able to conduct a thorough exam. Success!

Jennifer Chapman is a keeper at the San Diego Zoo. Read her previous post, Night Watch: Mission Accepted.


Sensitive Subjects are My Job

Hua Mei was the happy result of artificial insemination.

Have you ever been to a San Diego Zoo Safari Park and had the Africa Tram driver warn parents of little ones that it is that time of year when the animals are breeding and their kids might have some questions about what they saw after the ride? This usually gets adults chuckling, and maybe even leads to a few “birds-and-the-bees conversations.” Well, imagine your job is to help in the reproduction of endangered species and that every person you meet eventually asks, “So, what you do for a living?” As a laboratory researcher in the Reproductive Physiology Division of the San Diego Zoo Institute for Conservation Research, I’ve learned to say, “Think of us as a fertility clinic for animals.” Here are a few examples I use to explain this idea:

Artificial insemination
One of our lab’s greatest achievements was the birth of Hua Mei, the first panda cub to be born at the San Diego Zoo. While her birth was due to a large-scale collaboration of many people from all over the Zoo, including scientists, curators, veterinarians, and keepers, our greatest contribution was the insemination. It became clear that male panda Shi Shi was not going to naturally breed female Bai Yun and that human intervention would be necessary. Barbara Durrant, the director of our division, was able to collect semen from Shi Shi and use it to artificially inseminate Bai Yun, resulting in the birth of Hua Mei.

Sun bear Danum arrived with the help of estrous cycle monitoring.

Estrous cycle monitoring
Often when women are trying to conceive, doctors monitor their cycle using techniques to predict when ovulation will occur. Many of these techniques are not feasible to apply to our collection animals because they would require sedation. Instead, in addition to urine and fecal hormone monitoring, we collect vaginal cells and monitor changes using a modified Papanicolau stain and some good, old-fashioned microscopy work. The cells in many mammalian species have been found to change in color and shape as estrus progresses. Unlike the Pap smear women are familiar with, which checks for cervical cancer, we monitor the changes in vaginal cells, which requires a far less invasive method of collection. These cells can be obtained with operant conditioning or positive reinforcement training of the animal. It’s amazing what a sun bear will do for some honey water!

An example of a success achieved using this method is the birth of our first Bornean sun bear cub: Danum. A shift in vaginal cells from one dominant color to another, combined with behavioral observations by keepers and scientists, allowed us to pinpoint the right time to introduce the normally solitary male and female to each other with a decreased risk of aggression and increased chance of breeding.

In-vitro maturation (IVM), in-vitro fertilization (IVF), embryo development (ED)
Many of us remember the term “test tube babies.” Today, IVM, IVF, and ED techniques are being employed all around the world, enabling couples to have children despite a variety of fertility issues. Often a human female is given hormones to produce many oocytes (eggs) that are retrieved from her ovaries using ultrasound-guided aspiration. These oocytes are put into a medium specifically designed to help the oocyte mature (IVM) in preparation for fertilization. Sperm is then introduced to the egg in a petri dish (IVF) or by a procedure called intra-cytoplasmic sperm injection (ICSI).

The oocyte is then put back into the medium designed to promote embryonic growth in an incubator. That embryo is then implanted inside the female or frozen for future use. In our lab we are using these same techniques to try to produce embryos from endangered species. Our challenge is that we work with a variety of different species, all with their own special needs, and many of the oocytes we work with are from ovaries of animals that have passed away, leaving us one step behind in the maturation process. We have used these procedures on animals as common as cats and rabbits to animals as endangered as rhinos and polar bears.

It is no secret that the best part of this job for me is getting to see the fruits of my labor. I may be taking a petri dish that once contained oocytes and sperm out of the incubator and seeing a growing embryo, or standing in front of an exhibit watching an adorable sun bear cub climb up a tree stump, but the feeling of helping to create life is indescribable. My friends like to tell people I make babies. Well, if by babies they mean cubs, kittens, and pups, then I am happy to agree. It may not be the easiest job to explain to people, but I almost always get a response like, “That is so cool.” It is, and I finally found a way to tell people just how cool it is.

Nicole Ravida is a research coordinator for the Reproductive Physiology Division of the San Diego Zoo Institute for Conservation Research. Read her previous post, Creating a Sperm Atlas.