Developmental Milestones
Posted at 7:28 am March 21, 2006 by Suzanne HallAs Su Lin grows, it is useful to compare her development to our previous panda cubs in order to assess her progress. It may be interesting to note when she achieves certain milestones, but it is most informative about pandas when we can place these milestones in the context of panda cub development as a whole.
One major milestone for any panda cub is the transition from feeding exclusively on milk to feeding on bamboo. For many months now Su Lin has been mouthing and chewing various parts of the bamboo that is provided to her mother. In the early going, she was not actually consuming this food, but rather was practicing bamboo handling techniques that would later enable her to process it more efficiently. She currently chews the bamboo, probably ingesting the juice produced when the leaves are worked between her little teeth, but ultimately she is spitting out the remnants rather than ingesting them. No bamboo stools have been found by keepers to indicate she has eaten bamboo when no one is looking; in fact, Bai Yun is doing her job as a protective momma very well, since no baby stools of any kind have been found recently! Hua Mei didn't begin eating bamboo until her 11th month, while Mei Sheng started in his 12th month. We still have a little time before we would expect Su Lin to be eating bamboo.
Another major milestone in a panda cub's life is the onset of scent marking. The panda cub is able to use its nose for olfactory investigation almost from birth, but scent marking develops when the cub is physically capable of lifting its tail and rubbing against a substrate. Su Lin has been seen scent marking in the last few weeks. She's right on schedule when compared with Hua Mei, who was first observed marking in her 8th month. Mei Sheng didn't mark until a few months later. Interestingly, all three cubs first marked in the squat position, placing their scent gland down on a substrate while in a seated position.
By comparing Su Lin to her two siblings, and our large database of information about cubs in Wolong, we will better understand the range of normal behavior and developmental milestones for all panda cubs. You can be sure that we will keep watching Su Lin to assess her development. One thing I have learned over the last several months: I know you will be watching, too!
Suzanne Hall is the panda research technican for the San Diego Zoo's Office of Giant Panda Conservation.
Get the latest updates on Su Lin on our Panda News page.
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March 21st, 2006 at 9:37 am
Love to hear how each panda cub compares to previous cubs. Sure wish I could see more of Su Lin. Such a joy yesterday when I caught Tai Shan romping through the yard and performing summersaults - 2 of them. Between watching Su Lin and Tai Shan I now will be watching the Peregrine Falcons in San Francisco. They have laid 4 eggs. Boy! Do I ever keep busy.
Mary Lou - San Jose, CA
March 21st, 2006 at 10:02 am
I second that! I'd love to be able to see more of Su Lin. She's got quite a personality! It was adorable to watch her sample the bamboo for the first time, and I'm glad for the notes on her development. More as they come, please! ^__^
March 21st, 2006 at 11:18 am
As always Suzanne, thanks for the wonderful update. Isn't it interesting how our little girls have advanced quicker than Mei. Just like human children - girls advance and mature quicker than boys.
It's amazing how fast our little Suzie is growing up. And her cousin " Moose" Tai in Washington - what a big boy he is. But our Suzie is such a petite little lady. I just wish I could catch her at play. Keep the info coming - we love it!!!!
March 21st, 2006 at 11:25 am
I was trying to watch Princess Su Lin but the camera was focused on Mei Sheng instead. Mei Sheng has definitely grown into a handsome adult panda! It seems that he looks more and more like his papa Gao Gao each day.
March 21st, 2006 at 12:30 pm
Yes, you can be sure we are watching, Suzanne and SDZ Panda Team! I think I can speak for everyone when I say that we have definately been on the receiving end of a great Giant Panda education here and with the other Zoos. I, for one, have been hungrily soaking up any and all data I can find on these wonderful creatures and am forever greatful for your work and your ability to share it with us here. I am pleased to announce that I will be making a pilgrimage to the National Zoo in the fall (chosen mostly because I live on the east coast) and am entertaining the idea of a trip to SDZ soon. I'd love to see Bai Yun, Mei Sheng, Su Lin, and of course my big Daddy Mac Gao Gao before any of them have to leave this great country.
March 21st, 2006 at 12:39 pm
I just read the latest news from little Su Lin, I wish I had seen her play with the ball, did somebody see it on Panda cam? It's good to know that she's 27 lbs now.. she's getting big!
March 21st, 2006 at 1:48 pm
I've noticed Su Lin down with Bai Yun the last couple of afternoons. Seems her routine may slowly be changing. Once she was in the middle of a huge pile of bamboo, and was practicing her handling skills with aplomb. Suzanne, how long do mother pandas continue to clean up the cub's stools? Is it only while the cub is nourished completely by mother's milk? Is it done for her nutritional purposes, or to hide the evidence of a cub from potential predators, or both reasons, or neither? Thanks again for the informative blog.
March 21st, 2006 at 2:51 pm
Betty #7,
Female pandas ingest the waste of their young in the early months of life. There are two probable explanations for this: 1, to keep the area free of odor and debris indicating to any potential predator that her youngster is in the area; and 2, to recycle nutrients the mother is missing while fasting in the early stages of den life. Since Su Lin is out of the den and Bai Yun is feeding with abandon daily, the second explanation doesn't really explain Bai Yun's behavior… leaving us with option number 1! How long will she do this? We can't say, but it is likely to end in the next few months. By the one year mark I would expect we'll be seeing regular feces from the cub.
March 21st, 2006 at 3:04 pm
I was surprised to read that panda cubs start scent marking so early. In the wild, I assume it may be dangerous for the cub to let other pandas (especially male adults and predators) know that a cub is living in the area. How can this be ?
My second question is : do we know why only male pandas do the " handstand scent marking" ? thank you for your answer. I so appreciate this blog.
March 21st, 2006 at 3:47 pm
The other day Su climbed down to her mom at the base of the tree and Bai Yun looked towards the visitors with what looked like a big smile, like a mom proud of her little girl.
Su Lin seems to be in constant motion when she is not eating or sleeping. That is probably normal behavior for young pandas.
March 21st, 2006 at 4:18 pm
Gloria #9,
Panda cubs may simply be responding to interesting scents in the same way that adults do. Perhaps this behavior is so hard wired it is expressed even if such markings may advertise the presence of the cub. We do know chemical communication is paramount in the social lives of pandas, and evolutionarily the drive to scent mark may be irresistable. It's also possible that since early scent marking behavior tends to be high off the ground- in Su Lin's case VERY high, since she was observed today marking near her favorite perch in the trees- the scent marks would not attract much attention from predators. Another possibility is that the scent gland of such a young bear may not produce the same kind of high-power scent of an adult- since they aren't feeding on the same diet- and perhaps a predator wouldn't catch much scent even if they walked right over it. So many questions, so little time…
March 21st, 2006 at 4:35 pm
Suzanne #8-Thanks so much for that answer. Everyone is still learning so much from the relatively short time that pandas have been in captivity. I just saw a short video on ABC about the huge toddler panda group in Wolong. From their observations, the Chinese at Wolong are thinking that pandas may not be solitary creatures by nature but rather by the fact that there are so few others available with whom to interact. As we have seen, pandas seem to love company, human as well as panda, and might be with others if the food supply were plentiful enough.
March 21st, 2006 at 5:17 pm
Hello Suzanne and everyone,
I have continued watching Bai Yun and Su Lin every day, and reading all that has been going on with them both. I haven't been able to type and contribute to the comments for a while 'cos of medical problems. I am able to join in again now - Gosh I have missed being here.
It's such a joy to be part of all of the stages of Su Lin's development and to know that Mum is doing well.
Glad to be back.
Valerie Warburton - UK.
March 21st, 2006 at 5:40 pm
To #8 - Thank you for telling us about the report on Wolong and the thinking they have done about pandas not really being solitary by choice. Since some of us have mentioned that in the blog, and have thought that the availability of bamboo might be a factor, it's nice to hear they are looking at this as a possibility. Maybe it will cause the Chinese scientists to build more social interaction into their plans. The cubs of 2005 are really playful and it might be a chance to find out if those behaviors continue if they are given the opportunity.
Suzanne, can you let us know as the thinking develops about this? You do such a good job of writing panda reports and information to share with all of us. We appreciate the time you take. Many thanks!
March 21st, 2006 at 5:56 pm
Betty #12,
Although I agree that panda youngsters are happy to have company and are quite social, I don't think it is likely to be true for adults. There is a lot of aggression involved in encounters between adult pandas, even around the time of mating if the courtship isn't going very well. Female pandas rearing young are very protective and aggressive towards other pandas, even their own babies from previous years. The evolution of their bamboo feeding strategy certainly must be a driving force for such behavior, but even those cubs raised in captivity, who have the benefit of social interaction for some of their years, seem to grow into adults who are often aggressive to other pandas.
March 21st, 2006 at 8:49 pm
It was a quiet evening on Camera 4. Just before 7 p.m.(SD) Su was practicing her bamboo when mom arrived. It did not take long for a play session to turn into nursing time. Ten minutes later Bai and Su sat down opposite each other, Bai facing the camera, and separately attcked the bamboo pile. Since they were born, except for Su's tree climbing, whatever Tai was doing was replicated by Su 25 days later! It is great to learn when her sister and brother gained these essential skills.
My eternal thanks to everyone who enables us to see not just one Giant Panda cub but two daily from our homes or work as they grow. I agree with all the positive things mentioned in every one of the blogs and thank you everyone for sharing your thoughts, questions, observations, etc.
Just above the Panda Cam you have made note of the book signing by Joanne Ryder on April 8th. I have bought a copy of her " Little Panda" and it is a great " pacifier" for a pandamaniac when no bear is visible from any of the cameras. It also offers an instant pictoral reminder of how far our bears have come since they were born.
March 21st, 2006 at 9:24 pm
BettyB #12 - I was thinking along the same line. Perhaps they are solitary because in most cases they are the single child growing up with their moms. This might explain why so few male pandas know how to breed naturally. To avoid " familiarity breeds contempt" while providing enrichment from peers, perhaps we can have two or more same-sex pandas living together, father and son or mother and daughter for example. Hopefully there will not be " brokeback" moments :-).
March 22nd, 2006 at 4:58 am
We just saw a perfect example of how valuable all of the panda research has been to our undertanding of these beautiful bears: My daughter has a well-respected animal atlas copyrighted 1992, and the primary tidbit provided about pandas is that they don't walk well until they reach a year of age! My, has US research–and the panda cams!–proven that notion wrong!
March 22nd, 2006 at 7:57 am
it's so nice to read these weblogs from su lin's keepers. if it weren't for the blog and the new pix i'd never catch the panda princess at all. i always seem to tune in when she's waaaay up in the trees. it's nice to know that she's doing so excellently, the panda princess is a wonderful and beautiful little one and she's growing so fast.
March 22nd, 2006 at 9:28 am
it is 12:30 pm in baltimore and what a great shot of Su Lin in the trees. like you could reach out and touch her. i was treated this morning to tian playing with his mother as she was trying to eat something like a fruitsicle. how blessed are we that we get to see this stuff?! thanks.
March 22nd, 2006 at 9:47 am
Ok. What was Mei Sheng rolling in? Thanks for letting us see.
March 22nd, 2006 at 10:24 am
Suzanne, Do you know where I could locate a growth chart that measures the averages/norms of weight and length, etc. for giant panda cubs? We have them for human babies and I was wondering if such a growth chart exists for the cubs. You mention a database that keeps track of such information. I know that all panda cubs mature both physically and in behaviours at different rates, but I was just interested in the averages.
March 22nd, 2006 at 11:35 am
I think being solitary is, for bears, a survival mechanism. As Suzanne pointed out, they are aggressive and territorial creatures. They may congregate as adults for some special reason, but it is their nature to establish a hierarchy and to claim and defend territory. A really good illustration of this trait is when grizzly and Alaskan brown bears come together along river banks during salmon runs. A great number of bears gather in a small area, and there is food for them all, so they manage to tolerate each other for a time. But even then, the dominant bears get the best fishing spots and there are savage fights when a lesser bear fails to retreat or when a female with cubs feels threatened. And sibling cubs who may share a year or two of their lives will fight savagely if they meet later in life. Granted, Pandas may appear to be a more peace-loving species because they are more likely to eat bamboo than Bambi, but they are bears, and bears avoid each other as adults because they sense that a fight can result in loss of territory, dominance, or even life. Most bears would rather threaten and bluff their way out of perceived trouble, but given their natures, it may be a mistake to think that having enough food or keeping them together as babies is the key to helping them get along with each other.
March 22nd, 2006 at 1:23 pm
Pamela #23,
I think you are pretty right on there! Another couple of good points people need to remember are: 1- the young cubs who seem so social in those video clips would normally be with their mothers at that age. It's the most social time of their lives, and in the absence of their mother they fill their social needs -quite happily- playing with other youngsters and with their handlers. 2- as endearing as it is to see these little guys enjoying each other's company, to force a change in environment by requiring ADULT pandas to get along when they normally would choose to be solitary is a matter of imposing our will on the species. Why fight what has taken nature so many years to develop? The panda is not a domesticated species, and we should be careful of trying to deny their natural history for the sake of our interest in the " what if."
March 22nd, 2006 at 2:55 pm
I guess it's often difficult for us not to anthropomorphize, giving those traits we find so important for us to pandas and other species. Most people feel lonely without human contact, but do animals have these " feelings" also when not with their own kind? And if they do, how would we really know? We can infer from certain behaviors what they might mean, but we can't get them to " say" if it's actually true. (Except for perhaps the gorillas who were taught sign language and seemed to be " speaking" in our language). As Suzanne mentioned, we shouldn't try to force animals to behave in any particular way, but allow them to do what is natural for them.
March 22nd, 2006 at 3:26 pm
Did I imagine it, or was there a graph comparing the development rates of Hua Mei, Mei Sheng & Su Lin with this blog yesterday? If so, is it possible to show the graph with some explanations? Thanks!
Editor's note: We had tried to post a feeding graph to go along with Suzanne's blog, but it didn't reproduce well enough to view, so we removed it.
March 22nd, 2006 at 3:28 pm
Since the age at which pandas begin scent marking is being discussed, it is interesting to note that our precocious Mei Sheng began doing handstand scent markings at the tender age of 19 months — very rare for a male panda. I have photos documenting this milestone. I understand it is very rare for this to occur before sexual maturity.
March 22nd, 2006 at 5:16 pm
Thank you, Suzanne, for the comparative information among the SD panda cubs. The further conversation in these comments is also interesting and informative… thank you for continuing to educate us and fill in those question marks!
March 22nd, 2006 at 5:18 pm
I am watching Su Lin up in the tree right now, and boy, is she ever active! It seems that she could self-entertain up there by playing with the branches around her.
March 23rd, 2006 at 5:18 am
I wonder if someone would explain what " handstand" scent-marking is. Thanks.
March 23rd, 2006 at 6:21 am
Carole #27,
Yes, we were all quite surprised by Mei Sheng's hand stand scent marking… we found it hard to believe at first. One thing that is very interesting is that we have known only one bear in captivity who scent marked in the hand stand position as much or more than does Gao Gao… so maybe there is a strong genetic tendency playing out here. It certainly can't be true that Mei Sheng learned this from Gao Gao, since they are never housed together. Even their howdy gate experiences occurred AFTER Mei Sheng started up with the hand stands. Perhaps Gao Gao passed along a drive to get one's scent mark up high!
March 23rd, 2006 at 9:34 am
Suzanne, I've heard from a documentary on Wolong pandas that male pandas do the handstand position so they can get their scent-marks up high. The reason being, the higher you can scent mark, the larger bear you must be! Does this relate to establishing 'authority' and helping ward off other pandas from their territories?
March 23rd, 2006 at 12:51 pm
Margot #30,
a handstand scent mark involves the bear standing on its fore paws and lifting its rear up high to mark against the wall. Both back paws are off the ground. There are two forms of this scent mark: the contact mark, in which the animal actually rubs the gland under the tail against the wall, and the non-contact mark, in which the male doesn't rub the gland but instead urinates on the wall (or tree, etc.) and the urine splashes down the length of the wall. Most males favor the latter, but Gao Gao is really good at making contact in this position.
Bernice #32,
You are correct, the bears do have a reason to get their scent up high. Our research has shown that bears react differently to the same scent depending on how high up it is placed. There appears to be some important information conveyed in the placement. As to what exactly it conveys, dominance or strength or intimidating size are the likely possibilities. Very interesting since one of the most prolific handstand markers I have ever known, Gao Gao, is also one of the smallest adult males I have ever seen. Either he is trying to pass himself off as something he is not, or he has a healthy sense of self confidence!
March 23rd, 2006 at 2:16 pm
#33, Suzanne: The issue of handstand marking is fascinating. In eight generations of dogs we've bred, we have had two males and one female handstand markers. Genetics definitely play a part with these three, who are each two generations apart in the same line. It's especially amazing to see in small dogs, as this degree of foreleg strength and balance aren't necessarily present in everyone! Just as you mention about size, Suzanne, all of the dogs in this particular line are shorter in stature than those in other lines. What seems even more interesting with the bears is whether there might be a connection between the handstand marking and success in natural breeding. Gao Gao is so very special in his ability to understand " which end is up" and " get the job done with success" when it comes to breeding. Could it be that the handstand marking and natural breeding ability are related, both the result of some higher level of sexual awareness/understanding? Both behaviors are so rare–and result in such success–that they would seem to be related to some special, " survival-of-the-fittest" instinct.
March 24th, 2006 at 4:28 pm
I love the milestone updates!! I love hearing how Su Lin is growing up. I don't get to view the cam often anymore so this is the next best thing. THANKS!!!
March 25th, 2006 at 4:04 pm
The updates are great - thanks so much. Su Lin's cousin here in DC, Tai Shan, will soon rival her in tree-climbing skills.
April 3rd, 2006 at 9:28 am
As always, Suzanne, thanks so much for your insights and responses on your beautiful pandas. On a more personal note, I understand that the US has an arrangement with China to send pandas born in this country back to China at 3 or 4 years of age. Can you tell us the emotional reactions of the panda team on the day when it has to say goodbye to a panda " cub" it has known since its birth?
April 20th, 2006 at 4:54 am
There are so many beautiful pandas and y'all have them with y'all. Su Lin is the pretty one. To me they all look the same just a little bit. Well I got to go so keep them clean and safe
Bye