Babies Limit Breeding
Posted at 9:34 am April 3, 2006 by Suzanne Hall
It’s springtime, and the season for panda breeding has arrived. In the wilds of China and in some captive facilities around the world, pandas are focused on finding one another and mating. One zoo in the U.S. has already had a female cycle through her estrus and performed multiple artificial inseminations on her. In San Diego we have no such plans this year, because our only sexually mature female, Bai Yun, is still raising her youngster born last year (Su Lin, pictured here with a fruitsicle).
Does that mean there are no signs of breeding-related changes here? No! We have seen some shifts in behavior from our male, Gao Gao, which indicate that he would be ready to mate if called upon this season. His rates of olfactory investigation and scent marking have gone up a bit. This means he is actively searching for scent and is advertising his presence in the facility. Should Bai Yun go into estrus, he would know about it! But Bai Yun will not go into estrus. Past experience with Bai Yun’s other two cubs has shown us that so long as she is lactating she will not have a behavioral or hormonal estrus in the spring following a birth. From an evolutionary perspective this makes good sense, since her cub is not yet sustaining itself on bamboo. If Bai Yun were to get pregnant, she would need to wean Su Lin before she denned up again in the summer… and Su Lin is decidedly not ready to be on her own. If she were abandoned by her mother in the next few months in the wild, she would most likely starve to death.
Fortunately for our resident youngster, nature has ensured that Bai Yun’s milk production will limit her ability to get pregnant this year, and so Su Lin can go on enjoying the sustenance and company provided by her mother. Next spring will be different. Su Lin will be eating a lot more bamboo, as well as biscuits and other snacks. Bai Yun will be suckling her less frequently. At some point just prior to spring, Su Lin will wean. Bai Yun will likely undergo a strong estrus and Gao Gao will be ready and waiting. If we are lucky, they will be successful at breeding and we will once again be waiting expectantly for the arrival of another tiny panda cub in San Diego.
Suzanne Hall is the senior research laboratory technician for the San Diego Zoo’s Office of Giant Panda Conservation.
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April 3rd, 2006 at 11:50 am
Over the weekend, Mei Xiang at the National Zoo was acting very restless, marking spots and looking through the howdy gate window to see Tian Tian. It seemed as if she was responding to the interest he has been showing in her.
Have male pandas ever done like their carnivorous bear relatives and killed a cub to get the female to have an estrus?
April 3rd, 2006 at 12:36 pm
Thanks, Suzanne, for the estrus update. A lot of us have noticed the increase in male panda restlessness and vocalizations and wondered how the females were affecting this. As wonderful as it would be to have another new cub at SDZ, it’s good to know that Su Lin will have at least another year of her mother’s nutritional and emotional caring. Even though in captivity, Su would not starve by being displaced by a younger sibling, she might suffer in other ways from not getting her full time with Bai Yun. This way, she will learn more of the skills needed by a panda in the wild, even though she may never be in that position.
April 3rd, 2006 at 12:56 pm
Suzanne, does Wolong place its’ cubs in the “Kindergarten” to increase the speed of breeding in captivity? We know that Hua Mei had twins in 2004 and 2005. I think we are all happy that we will have Su Lin on camera for another year, as well as Tai, to teach us how to eat bamboo.
Thanks for all your teaching and response to our questions and thanks to all the other pandamaniacs who have shared their knowledge, opinions and observations. In the new blog format are our previous comments on other subjects still accessible?
Editor’s note: Yes, comments on previous blogs can still be viewed by clicking on “Comments” at the bottom of the blog you are interested in.
April 3rd, 2006 at 1:17 pm
Great camera work on the pandacam. Captured a great play session with Bai and Su Lin. Thanks for giving this increased attention.
April 3rd, 2006 at 1:37 pm
Carole at #4, you are so right. Look who’s sneaking Momma’s bamboo! And was a game of hide-and-seek part of that play session? It’s so much fun to see Bai climbing. Absolutely captivating!
April 3rd, 2006 at 1:56 pm
Hopefully Bai Yun and Gao Gao will have another baby next summer! Another little boy cub as sweet and as cute as Mei Sheng is. The Panda cam is focused on Mei Sheng right now as he sits with his back against that housing log, just munching away on the bamboo looking absolutely content and at peace. I’m going to really miss Mei Sheng when he has to go to China. He is truly the sweetest Panda! My favorite Panda too
Wishing all the best to Zoo Atlanta! We all hope that Lun Lun and Yang Yang will have a baby this summer!
April 3rd, 2006 at 2:16 pm
It would be interesting to observe Mei Xiang and Tian Tian next year. Perhaps after nearly 2 years of separation, the couple will finally breed naturally. Given the amount of interest Mei Xiang and Tian Tian have shown to each other now, it appears that they are ready to breed naturally. Poor Gao Gao! Can a male panda breed with more than one female panda per season? I am wondering if Pan Pan did so in the past since he has been so successful.
April 3rd, 2006 at 2:45 pm
I noticed that Bai Yun is kind of old compared to Mei Xiang. Is there an age cap for panda breeding? Do female pandas have “menopause” like humans where we’d have to stop breeding them?
April 3rd, 2006 at 4:41 pm
Thanks for the very nice close-ups today. It’s wonderful to see them so clearly. We can almost reach out and touch the bears, making it easier to see what Su Lin is doing with the bamboo leaves and Mei Sheng contentedly eating his.
Their play sessions after are so enjoyable to watch. I never get tired of seeing what they’re doing. :slmile:
I’m leaving to go on the SDZ trip from SFO on Thursday. We’re going to Wolong and Chengdu to see the pandas and will also travel all over China for three weeks. It’s hard to wait for all the fun. Take care everyone and we’ll “talk” after we return from PandaLand.
April 3rd, 2006 at 7:28 pm
Rita,
Although I would not rule out the possibility of a male panda killing a cub, it isn’t very likely. Unlike lions, who live in social groups, male pandas don’t have ready access to cubs. Additionally, the lioness will come into estrus quickly after losing her cub, but the panda female only comes into estrus in the spring, so killing her cub in, say, November, wouldn’t serve a male panda much purpose. He wouldn’t hang out with her for several months because they would both choose solitude.
Kay,
Captive panda males can breed with more than one female per season if they are given access to her. This is also presumably true in the wild, because male home ranges overlap those of multiple females.
Grace,
Most panda females stop being reproductively successful at about age 18. Bai Yun has had a great diet in San Diego and she hasn’t given birth as often as many of her captive Chinese counterparts, so perhaps she may be able to give birth a little later in life… but we’ll have to wait and see.
April 4th, 2006 at 8:28 am
Love this information! I have a question:
I have been wondering if giant pandas have tongues similar to cats. I’ve noticed that Bai Yun and Mei Xiang both groom Su Lin and Tai Shan, respectively. I cannot recall reading anything regarding “tongues”. Thanks so much!
April 4th, 2006 at 9:47 am
Suzanne, I too am wondering (like #3 Bernice above) about the Wolong kindergarten and that they took them from their mothers. Is it to move the breeding along? Don’t these babies ‘miss’ their mothers? I sort of feel sad for them, that they don’t have that contact. Who will teach them to eat bamboo? I saw some recent pictures of the kindergarten 16, and they certainly have grown a lot and when looking at them all together, they look like stuffed animals! I don’t know how they tell them apart! (Probably tagged somehow). I also saw a picture of one of Hua Mei’s twins; they must be part of the 16? I wonder if the moms miss their babies??
April 4th, 2006 at 1:43 pm
What a cute picture of Su with a fruitsicle! Is this a treat or a new part of her diet? What changes occur in the nutritional quality of the mother panda’s milk to support the baby’s growth and activity requirements during the first year? Does weaning occur spontaneously because the baby is less interested in nursing when getting nourishment from bamboo so milk production decreases due to lack of mammary gland stimulation; or does the mother’s milk supply begin to decrease toward the end of the first year and thus force the “hungry” baby to eat more bamboo?
April 4th, 2006 at 2:25 pm
It looks like Su Lin is having a “rock” day. She’s playing with some moderate size rocks in her exhibit and seems to be having a good time. I wonder if the keepers placed the rocks there as enrichment items for her. She is just having fun with them!
April 4th, 2006 at 3:16 pm
Charlotte #13,
I don’t think we know the answer to your first question. Panda milk content has been studied to help develop an ideal formula for infants being hand raised, but that is a focus on early stage milk quality. To my knowlege, any change in milk quality towards the latter half of the mother-infant relationship has not been studied. As to the cause of weaning, however, I will say that in my experience it is rare for the cub to have nursing rejected by a dam who is attempting to “force” her cub to eat bamboo. Rather, the cubs spend greater and greater lengths of time away from their mothers, and wind up supplementing their diet with increasing amounts of bamboo as time goes by. A final weaning for cubs in the wild is probably abrupt, as females den up or males run cubs off during a breeding season. In all truth we do not know for sure.
April 4th, 2006 at 3:46 pm
I’ve been thinking about Hua Mei lately. Please let us know how she and her cubs are doing. I’d love to see some photos of her and the cubs. Thanks, Cindy
April 4th, 2006 at 8:15 pm
I just got back from Washington DC where I visited Tai Shan! I spent 2 hours watching him sleep up in his new favorite tree. I just can’t get enough of these babies! They are doing a ton of construction around the panda exhibit and I was surprised that the sounds of jackhammering didn’t bother them. I will be in San Diego in June and can’t wait to visit with Su Lin.
April 5th, 2006 at 5:01 am
My, it looks as if you have torrential wind today in SD! It’s only 5:50 AM your time, but Su Lin is on top of the lair; the trees are whipping about wildly, and she is not happy! Dorothy trying to get into the storm cellar in Wizard of Oz comes to mind! I’m so hoping that she thinks to jump over the edge and use the lair for shelter. There’s no sight of Bai Yun–perhaps she hightailed it inside at the first inkling of this whirlwind!
#15, Suzanne: For what it’s worth, canine milk is visibly thicker near weaning than it is at birth. I’m not altogether sure why this is, although it might seem that this provides for easy digestion at birth when the colostrum is all-important, while it also provides for the higher caloric needs of pups who are ten times their birth weight near weaning. If this is true in pandas, it would certainly account for the continued weight gain of Su and Tai.
However, where on earth do pandas get fat in their diet to provide not only such high-fat, nutritious milk for their cubs, but essential fat-stores in their own bodies?
April 5th, 2006 at 6:02 am
Su LIn looks adorable in that picture. Had she had a “muddy day” again?
April 5th, 2006 at 6:10 am
Great information and, as always, thank you very much for your attention to our questions, Suzanne. I, like Susie, have been wondering about the panda’s tongue. Is it rough, like a cat? Or smooth like a dog’s tongue? I know when my cat licks my face it’s almost painful! But then, I don’t have the thick fur and skin of a panda cub.
April 5th, 2006 at 7:21 am
Suzanne, thank you for the response re. panda milk and weaning. Nature can seem rather “heartless” with its young when forcing them to grow up into adulthood. I guess it’s all part of survival of the fittest.
April 5th, 2006 at 7:48 am
I agree with Charlotte #13. The picture of Su Lin with the fruitsicle is darling. Makes me want one, too. A fruitsicle, that is - not a baby panda. That would be too much.
April 5th, 2006 at 8:11 am
Su Lin looks darling with the fruitsicle and she seems to have a firm hold on her treat. Yesterday, Mei Xiang and Tai Shan looked cute sitting toe to toe happily licking the same fruitsicle for quite a while, until Tai finally had his fill. Mei was very generous with her treat.
April 5th, 2006 at 11:52 am
What a dirty cub Su Lin is. Did she roll in the mud again?
April 5th, 2006 at 2:15 pm
Suzanne, I am curious if you can tell how many people are watching the Panda Cam at any given moment?
Editor’s note: Our Web Services Division can retrieve that information when needed.
April 5th, 2006 at 4:58 pm
Hello Suzanne, thank you very much for your answer. You are so wonderful! Our pandas are so lucky.
April 6th, 2006 at 8:21 am
It suddenly occurred to me that when Su Lin does wean, and if Bai Yun does become pregnant, you will eventually have a housing issue - Su Lin will need her own “room.” I am sure you are preparing for that as part of your overall program. Where will Su Lin live?
April 6th, 2006 at 9:39 am
Yippie, I’m back. I just moved and wasn’t able to see the Panda Cam for almost a month! Su Lin has grown so much and the leaves are all grown in. So many changes in such a short amount of time. Has Su Lin given another interview lately???
April 6th, 2006 at 10:52 am
Deborah #27,
Our facility can house Su Lin even if Bai Yun gives birth again. We have 9 bedrooms available, although we wouldn’t want to house that many bears. We have four large enclosures (2 exhibits, 2 off exhibit) and two grass-covered garden rooms. We could probably house four to five adult bears very comfortably, maybe six… and cubs with mom would live in the space Bai Yun has so they wouldn’t count when partitioning the space. We are ready for these scenarios!
April 6th, 2006 at 12:33 pm
From your lips to God’s ear, Suzanne! Thank you for all the information about mating and raising cubs. I’m trying not to get my hopes up of a baby cub here in Atlanta, but it’s hard. I’ve learned so much from you and your staff.
April 7th, 2006 at 10:24 am
As usual, thanks for the wonderful info, Suzanne. And my, what a dirtly little girl Susie is in that picture. Did she have another roll in the mud?!?! She looks so petite and cute I can’t get over it, especially knowing that Tai just weighed in at a whopping 44 pounds - about 16 more than our little Susie. You’d never know they’re only a little over 3 weeks apart in age. Looks like Susie Q might take after her daddy and be a smaller bear. Can you tell us, Suzanne, how Susie fairs at her age compared to her older sister and brother, weight-wise?
I have yet to catch Bai and Susie in a play session, but Tai and Mei sure keep me in stitches - what a playful pair they are. You’d think Tai would get tired of falling off those tree limbs, or being rolled down the hill by mom, but he just keeps coming back for more:o). Suzanne, is the difference in their play (Tai and Mei vs. Susie and Bai) possibly because Mei is so much younger than Bai - she’s not quite 8 years old? And, I guess, it could have something to do with Tai being a little boy bear and more rambunctious than our sweet Susie.
Thanks again, Suzanne, and all of you special people at the SDZ.
April 8th, 2006 at 6:29 pm
I often see Bai Yun giving her baby Su Lin a tongue bath. Su Lin is still small enough for Bai to hold in her arms and flip over to check out her diaper. So cute!
Mei Xiang can no longer hold big boy Tai Shan for a bath. So she approaches him around midnight when he is sleeping on the raised platform. She looks just like a little mom, standing next to the “changing table”
My question is: does the tongue bath cause pandas to cough up hair balls?
April 13th, 2006 at 4:49 pm
It’s about time for Bai Yun to stop trying to bathe her baby, isn’t it? It’s kind of funny to see her tackle Su Lin. Bai puts her head down at times to encourage Su to tag her and play.
Beautiful Mei Sheng. When I see Tai Shan at the National Zoo play with his mom it reminds me so much of Mei Sheng and Bai Yun.
Do you see similarities in the personalities of Su Lin and Hua Mei?
December 15th, 2006 at 6:40 pm
I love pandas. Baby pandas and adults, too. I want a panda for my 16th birthday. But I already have a cat and a dog. They are so so cute but baby pandas are so, so, so, so, cute. I might just vist the big and little pandas at the san diego zoo.