evolution of opposable thumb

[Lisa Rogers <eqwq.lrogers@xxxxxxxxxxx>]

In reply to:  Adam Rose <adam@xxxxxxxx>
Date: Mon, 15 Jan 96 09:37:40 GMT
Thanks for this post.
Lisa, do you happen to know if any other primate can touch its little
finger with its thumb ?

Lisa:  You're welcome.  No, I don't, tho I suspect our closest
relatives can.  Of course, our hands are a bit different, just not as
much or as recently as sometimes thought.

BTW, the saddle shaped rotational thumb joint shared by humans,
chimps, bonobos and gorillas is a result of our common ancestry.  It
was a common ancestor, perhaps around 10 mya that first possessed
that structure.

Gibbons are more distant relatives than that.  Their equally
rotational opposable thumbs evolved separately, with the ball and
socket joint.

Just makes me wonder exactly what it is that apparently provided an
advantage for increases in precision and power grip in both groups,
and among members of both groups ever since.

Primates share the possession of fingerprints and oil/sweat glands on
the gripping surface of the hand, which both contribute to tactile
sensation.  We all have much more sensitive hands than other mammals.

Lisa

I just wonder what all those gibbons



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