The other example is the thumb of the giant panda, another favorite example of Gould's.

The giant panda has a thumb that it uses to strip leaves from bamboo stalks in order to make them easier to eat. It can't move much, but can squeeze against the fingers (and true thumb) to hold bamboo.

http://www.athro.com/evo/pthumb.html

However, the "thumb" is not really a digit but rather an enlarged radial sesamoid, a bone that grows in joints.

Sounds like a pretty good adaptation, right? Giant pandas evolve an enlarged radial sesamoid in order to better eat bamboo.

http://www.athro.com/evo/pthumb.html

It turns out that grizzly bears do not have this enlarged radial sesamoid. It also turns out that giant pandas have this enlarged radial sesamoid in their hind feet as well.

What does this imply?

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