Panda Ducklings?

Dr. Pye jots down measurements being taken by Dr. Mike Schlegel, Zoo nutritionist, and Dr. White.

Dr. Pye jots down measurements being taken by Dr. Mike Schlegel, Zoo nutritionist, and Dr. White.

The veterinarians had another chance to examine our new panda cub on Thursday, September 10, and in doing so, Dr. Geoff Pye made an interesting discovery: this cub has webbed feet! There is a small stretch of skin between two toes on each of the back feet. While not a common trait for pandas, this has been very common to the population of pandas at the San Diego Zoo…at least since Gao Gao came to us. He, too, has webbed feet, and he has passed this trait along to each of his four panda cubs.

What could be the purpose of such a physical trait? It is unlikely to be a swimming adaptation. Pandas are not known to be regular, avid swimmers, although they do cross water when necessary in the wild. Perhaps this confers some specialized bamboo handling skill? Again, not likely, since the webbing seems restricted to the back feet rather than the forepaws.

There might be some benefit to adult males with webbing when engaging in foot scraping behavior. This interesting behavior is often seen when males are in high states of arousal around breeding encounters or when aggressively engaged with other adult males. Foot scraping with the hind paws leaves long troughs in the dirt, a visual signal, but may also leave some scent behind. We believe polar bears can leave pedal scent when they walk, and perhaps a panda’s foot scraping leaves some such scent behind as well. Either way, would webbed feet play a role in heightening the result of foot scraping? Since this behavior seems largely limited to males, and all of Gao Gao’s female cubs also have this characteristic, it may not have anything to do with this social signal at all.

One thing this webbing does highlight: Gao Gao is a valuable panda in the captive breeding program. Originally found near Fengtongzhai, he is likely to be at least somewhat genetically distinct from the wild pandas found in Wolong reserve. Characteristics like webbed feet underscore the unique genetic contribution our adult male can make to panda propagation.

Though webbed feet are an obvious sign of inheritance from Gao Gao to cub, undoubtedly there are more subtle genetic traits passed down as well. Personality, feeding and breeding success, general health and body size are all likely to be influenced by this to some degree. We’ll have to wait a little longer to see if this little boy is as mellow as his father, or as small, or has the same propensity for hand-stand scent marking.

I am sure you will enjoy watching and learning along with us!

Suzanne Hall is a senior research technician for the San Diego Zoo’s Institute for Conservation Research.


Watch the bears daily on Panda Cam.

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