Causes of Bipedalism: Improved Viewing Distance

Outline

Largely based on the then established assumption that humans evolved on the savannah and that man was a hunting animal, it was a reasonable theory that greater viewing distance, both in terms of looking for predators and prey, would be a selective advantage. The 'merecat' theory is quite a plausible idea when you first hear it until you realise that merecats and bears, which also have this standing viewing behaviour, still get down on all fours to move.

Largely discredited today.

Authors

Attributed to Dart (1959) but it was very much a function of the savannah theory.

Location

African savannah.

Selection Pressure

Every individual member of a group could conceivably benefit from this adaptation although this is blurred by some group selection. Clearly an ape would be able to raise their stature more if they got up on their hind legs. If another member of your group has stood tall and then spotted a leopard, you might benefit from it too.

Intermediate Steps

This theory works quite well as an early reason for a hominid to stand erect, but it is hard to see how this specific behaviour would then have led to bipedal locomotion. 

Both Sexes?

Applies to both sexes equally.

Explains Australopith Anomalies

Australopith morphology does not seem to indicate that standing erect was a key part of their repertoire.

Why not Pan? Observed in Pan?

Chimps have been observed standing tall to gain a better view for very short periods of time, but again the behaviour has not been seen for any extended period of time.

Links with other Theories

This theory is very compatable with most of the other theories.

Popularity

It is an old and popular theory. Listed in 5 out of 8 of my sample textbooks.

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