Xiao Liwu: Meeting those Milestones

Mother and cub engage in a wrestling session.

Mother and cub engage in a wrestling session.

I have had the opportunity to observe panda mother and son, Bai Yun and Xiao Liwu, quite a bit lately, and I have noted that the cub’s behavioral development appears right on track with respect to his siblings. He is at an exciting age for a panda, a time when the learning curve is a little less steep than it was a few months back, and Xiao Liwu is busy exploring every nook and cranny of his environment…when he isn’t napping, of course. Babies do need their rest!

One of the major milestones our little boy is working on is bamboo feeding. Now, he isn’t yet ingesting it as a food staple. Xiao Liwu still relies on mother bear to provide him with milk to satisfy his caloric needs. But he is learning to handle the leafy material, working it in his paws and practicing with his pseudothumb. The cub spends time mouthing bamboo, stuffing a leaf or two in his mouth and chewing, chewing, chewing…until he ultimately spits it out. No doubt there has been some incidental ingestion of the plant, but as the necessary teeth are not all in place yet (that occurs at about 12 months of age), he doesn’t have the tools with which to begin efficiently processing bamboo. That time is coming soon, however, and in the next few months, we will begin to see him regularly ingesting the plant that will become his staple dietary ingredient.

Play is an important part of his behavioral repertoire at this time. Play is often scientifically defined as an apparently purposeless behavior, because it doesn’t provide an obvious payoff. It doesn’t help a panda obtain food, or secure a mate, or ensure safety and survival. Yet for a cub, play is an important part of healthy development. Locomotory play, including frisking about on the ground and twirling around in the trees, helps to develop strength and coordination as the cub learns to control his growing body. Object play allows the cub to effect control over elements in his environment, influencing the development of his confidence and coordination. Social play teaches him the nuances of interacting with others of his species, including how to read and deliver appropriate social cues. Yet this “purposeless behavior” may only seem purposeless in the immediate sense. There are payoffs down the road, associated with neurological development and perhaps even learned behavior.

Play is a behavior that peaks in the late juvenile period before bottoming out as the bear becomes an adult. Interestingly, the juvenile period is also the time of greatest growth of that portion of the brain known as the cerebellum, an area that plays a role in coordinating smooth motor function. Adulthood, as we all know, is the time when we take on the mantle of caring for ourselves, and for the panda that means spending most of its waking hours foraging and feeding. There must also be time for procuring a mate or rearing young. There is little time for frivolity, and efficiency matters. By the time a mammal has reached adulthood, its neurological development is complete, and it can now reap the benefits of what its brain has been trained to do.

But while scientists are still unraveling the mysteries of the function of play, you can simply witness the fun as Xiao LiWu continues on his developmental journey. Enjoy it while he is little, either in person or on Panda Cam, because one thing this scientist can tell you definitively: watching that panda cub play is absolutely charming!

Suzanne Hall is a senior research technician for the San Diego Zoo Institute for Conservation Research. Read her previous post, Through the Bear Lens.

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