Re: fossil foot bones

Phil Nicholls (
Mon, 16 Oct 1995 06:23:20 GMT (H. M. Hubey) graced us with the following

>Alex Duncan <> writes:

>>ALL of the fossil foot bones from 3.5 Myr are consistent w/ the view that
>>early hominids retained pedal grasping abilities. What is unscientific
>>about assuming hominids w/ grasping feet used those feet for grasping?

>There are two reasons (using your kind of logic of evolution);

>1) The grasping would have had to stop way before the grasping foot
>disappeared otherwise the grasping foot would have never disappeared
>since they'd always be using it to grasp.

Changes in behavior usually come before changes in morphology.
As the amount of time hominids spend out of trees increases pedal
anatomy becomes more and more re-organized to support the stresses of
bipedal locomotion.

>2) The walking foot (i.e. non grasping foot) would have had to
>appear at some time, but the fact that the walking_foot did not
>appear until millions of years after they started walking
>doesn't seem to bother you when you make the kinds of statements
>that you make all the time.

The australopithecine foot is primarily a walking foot that retains
some grasping abilities. It does not bother us because, and I can't

>Chimps still don't have "walking_feet" but walk.

About 10% of the time.

>YOu always look
>at everything from a heavily biased version and never consider
>it from another perspective. This gives the wrong idea of
>distance. If we didn't see chimps but only their bones should
>we have assumed that they never left the trees?

On the contrary, I can point out several features of the chimpanzee
skeleton that are adaptions for terrestrial locomotion. We also know
that most primates are capable of bipedal locomotion so I don't see
your problem.

>Well, since
>we were told that they spend 90% of their time on the ground
>even with their "grasping feet", how much of their time
>did they spend on the ground when they only had "significant
>climbing ability"? HOw much more would it have been if
>they only had "very large climbing capability"? How about
>if we changed these phrases to :

> not insignificant
> very significant
> quite significant
> reasonably significant
> blah blah....

Reconstructing fossil behavior is not expected to produce the same
degree of accuracy as an ethologist. However, the ffeet, the
handbones and limb proportions all are consistant with some
arborealism. If that is not good enough for you, then I am sorry.

Phil Nicholls
"To ask a question you must first know most of the answer"
-Robert Sheckley