panda weaning process


Weaning Xiao Liwu: Leafy Greens

Xiao Liwu is surrounded by leafy greens.

Xiao Liwu is surrounded by leafy greens.

After many days of short separations, giant pandas Bai Yun and Xiao Liwu were doing well. Both bears had a few hours each morning to be on their own, and both spent that time eating heartily. Reunions between them at the midday feed were non-events. Although occasional nursing bouts were observed, it did not appear that the frequency of nursing had been accelerated. Further, the duration of observed nursing bouts was very short, lasting only about two minutes. This suggested that either mother Bai Yun’s milk supply had begun to dwindle or that the nursing was more about comfort-seeking than calorie-seeking on the part of our youngster, Xiao Liwu.

Since no other comfort-seeking behaviors had been observed, we opted to move forward with our weaning protocol. Last week, we lengthened the time the two bears are separated. The two are no longer reunited at midday and instead are separate still as they are served lunch. Access to each other is now delayed until the end of the workday, when the last keeper is ready to head home.

Did you notice? Probably not, since the bears showed no overt response to this change. We have only one report of “Wu” knocking on the door that separated mother from son, and it was a brief event. They are both taking this change very much in stride. In fact, by all accounts, Wu seems to be handling this separation better than any of his siblings. He is a very relaxed bear.

I can’t say why it is that he seems so much better able to adapt to the weaning process than his siblings. Perhaps it is because of his penchant for bamboo. He still refuses to eat anything but his leafy greens, despite our keepers’ gallant attempts to offer him something—anything—that he might like as an alternate treat. We know that adult pandas have to spend a lot of time feeding on bamboo to meet their caloric needs. Perhaps Wu is not so concerned about weaning because he, too, is very focused on bamboo feeding. To get his calories, he isn’t relying on carrots and apples and Gao Gao bread and honey-soaked softened biscuits (keepers have been really trying to entice him!), so he has to take in as much bamboo as he can get his paws on, and there is little time to worry about his mother.

In fact, these weaning separations may be helping him to some degree. Our little panda actually gained some weight in the first nine days of our separation protocol. Perhaps having the bamboo all to himself is beneficial to him. It will take some time, and several more weigh-ins, to see if his weigh gain trajectory alters as a result of weaning separations.

In a short time, if both do well, we will be looking to complete the weaning process for Xiao Liwu. Though some of the details have yet to be worked out, be sure that our keeper staff stands ready to provide Wu with the added social support all of our past cubs have needed once he is independent of his mother. All of our previous cubs have incurred a short period of pining for their mother after weaning was complete (generally not reciprocated by Bai Yun, they’d be sad to learn), but perhaps our bamboo boy will pine the least of all. He’s very busy, after all, getting in those leafy greens.

Watch our pandas daily on Panda Cam.

Suzanne Hall is a senior research technician for the San Diego Zoo Institute for Conservation Research. Read her previous post, Weaning Xiao Liwu: Conflict over Calories.


Weaning Xiao Liwu

Xiao Liwu enjoys a bamboo lunch in his expanded habitat.

Xiao Liwu enjoys a bamboo lunch in his expanded habitat.

When a giant panda cub is totally weaned from his mother in the wild places of China, one of two things likely happens: either his mother runs him off with aggressive behavior, as has been noted with some brown bears, or the mother and cub simply wander away from each other and begin separate lives. Many panda fans worry that that final weaning event is a sudden change for the bears, but in reality it is the culmination of a longer process that begins some months before, when the cub develops his bamboo-feeding dentition.

At about a year of age, the cub’s diet changes from one of 100 percent maternal milk to one incorporating his staple adult food, bamboo. He starts by feeding on small quantities of leaf, mastering the process of chewing and swallowing a solid food. Gradually, the cub ingests more and more bamboo and needs less caloric support from mother’s milk. By the time a final weaning separation occurs, he may only have been nursing once a day, or even skipping days between suckling bouts. The development of this nutritional independence takes time, and thus, weaning is not accomplished overnight.

Xiao Liwu turned 18 months old on January 29, 2014, and we have begun preparations for weaning him from his mother, Bai Yun. Many of you have noticed changes in the access given to our mother-cub unit, as they are now regularly seen exploring both the left- and right-hand exhibits. We have opened the door between these two usually separate spaces, allowing the pair to freely explore either side, moving independently or together as they see fit. This is an opportunity for both animals to become comfortable with the right-hand exhibit, which Bai Yun hasn’t seen in nearly two years; the cub has never experienced it before.

During this period we will be watching the pandas to see how they are utilizing this newly enlarged space. Do they spend more time in close proximity or separate? Does the cub follow his mother everywhere or explore alone? Does Bai Yun seem to move away from her cub when he approaches? The answers to these questions will tell us more about Bai Yun and Xiao Liwu’s readiness for weaning and will inform our decision-making as we move through this process. We aren’t in any rush here.

The weaning period is sometimes a difficult one for our blog readers and panda fans. There is often concern about the well-being of our bears during this time. Bear in mind, however, that a zoo setting is unlike a wild one in that there are barriers to animal dispersal. Simply put: our animals reside in enclosures, and they are not free to wander away from each other as they might in the wild. We have to help them adhere to their natural tendencies by opening up new spaces.

By making changes to the access our bears have to the spaces around them, and to each other, we are facilitating a natural process that is taking place in wild habitat even as we speak. In doing so, we are respecting the health and well-being of both mother and cub, guided by the best practices that biology, science, and husbandry allow.

I will update you periodically as to the status of our weaning process. In the meantime, I encourage all of our newest panda fans to read up on past weaning events with other panda cubs, in blogs such as:

Weaning Panda Cubs

Weaning Zhen Zhen: And So It Begins

A Big Step Forward

In these, you can find more details about what we know about this period in a panda’s life and the importance of remembering that this is not just about the cub but also the mother. You can get a flavor for how the process unfolds and how past cubs have responded to our weaning protocols. After eight years of blog-writing, our panda archives contain a wealth of information that you can access to learn about this and any other panda-specific topic you might be curious about.

One final note: To make room for our mother-cub pair and changing needs, we have moved Gao Gao to our off-exhibit area. You may see less of him on Panda Cam, but he is still here, happily munching away on bamboo and getting lots of attention from our staff. He won’t be back on exhibit again for about a month, as the weaning process will be focused in the main exhibit spaces.

Suzanne Hall is a senior research technician for the San Diego Zoo Institute for Conservation Research. Read her previous post, Yi Lu Ping (Have a Good Trip), Yun Zi.


Yun Zi: Calm and Mellow

The 18-month mark is right around the corner for giant panda Yun Zi, and so far he is adjusting perfectly to not always being around Mom. Since they’ve been given access to both exhibit spaces in front, Yun Zi has spent most of his time in one enclosure while Bai Yun is enjoying the space in the other.

For a couple of days now the doors have been shut from the time of morning feeding to the mid-day feeding. The two bears have been doing extremely well on their own. Bai Yun doesn’t look for her cub; instead, she enjoys the time to herself and eats well, knowing that she doesn’t have to share. Yun Zi is doing well also; most of his time is spent sleeping and exploring the new-to-him exhibit. He enjoys the climbing structure there and has shown how calm and mellow he can be.

One of the days that they were re-united, Bai Yun pushed Yun Zi out of the way so that she could get to the biscuits hidden on “his” side of the viewing area. The cub isn’t showing any effort to nurse during the day, and he’s been getting smarter at stealing Mom’s bamboo. Bai Yun is doing her best to keep him away as she eats, but the two do go back and forth between the two enclosures, picking at the bamboo left there by the other.

They are doing so well through this transition, and we will be moving at the bears’ comfort level. We will do our best to keep everyone updated.

Anastasia Horning is a panda narrator at the San Diego Zoo. Read her previous post, Our Growing Panda Boy.


So Far, So Good…

Yun Zi: Soon to become independent.

Things have been going well in the San Diego Zoo’s panda exhibits for Bai Yun and Yun Zi. Both bears seem comfortable and relaxed with access to the area formerly occupied by adult male Gao Gao. In fact, as I write this, Yun Zi is high up in the climbing structure in that exhibit, sound asleep; Bai Yun is feeding happily in the other exhibit. The bears are about as far away from each other as they can possibly get.

Which, in fact, is the point.

Tomorrow, the panda keepers will begin to close the door between mother and cub for a few hours each morning. If they did this today, right now, it would have no effect on what these two are doing: Bai Yun would likely continue to feed, and Yun Zi would continue to sleep. In fact, in past years the closed door of the first step has often gone undetected by the bears for days!

If one of the bears discovers the door closure, there might be some initial confusion or anxiety evident as a result, especially for Yun Zi. This is entirely normal. We anticipate that even if the first step goes unnoticed by the pandas, at some point in the process the cub will clue in and be unhappy about his inability to access his mother. This is something we have seen with every cub here, and as Yun Zi is a healthy, typical panda youngster, he will be subject to it, too.

Nonetheless, we will close the door each day for nearly a week as an incremental step toward full separation. The animals will reunite at lunchtime and remain together until the next separation the following day. During separations, each bear will be provisioned with ample food and some enrichment to keep them occupied.

Bear in mind that weaning is always hardest on the cub. Bai Yun’s reaction to the separations will likely be more subtle, and her behavior will return to baseline more quickly. Our data suggests that with each subsequent cub she is more adapted to this process and is ready to move beyond cub rearing when the separation is finalized. This is part of her normal life cycle, a recurring series of breeding and birthing and rearing of young, set to renew itself again.

Please note also that staff is, as always, keeping an eye on the progress of our charges. We are prepared to offer our young panda what means we can to assist in his transition to independence. On the tail end of the separation process lies a garden room, where Yun Zi will be able to see his keepers several times each day. They will offer him special training sessions and opportunities to bond with them, and this activity will provide him with the extra TLC he may be craving at that point. We’ll take good care of Yun Zi.

We will continue to keep you apprised as the process unfolds. Keep rooting for Yun Zi!

Suzanne Hall is a senior research technician for the San Diego Zoo’s Institute for Conservation Research. Read her previous post, Panda Acclimation.