Elaine Morgan's letter to The Guardian...
“Upright
walking”, theorises Professor Crompton, (Science, June 1st) “evolved
in the ancestors of all apes, including humans, as a means of foraging for food
in the small branches.”
If
so, then when and why did our closest relatives, chimps and gorillas, abandon
this “very effective” practice? Why don’t all descendants of this putative
ancestor habitually cover the ground on two legs? African apes walk on their
knuckles. Orangs have evolved fist-walking. Chimps on the forest edge do indeed
stand upright to pick fruit but instantly drop onto four legs for locomotion:
they find it easier and faster. Why didn’t our own ancestors find it easier and
faster?
There
is only one environmental factor which invariably induces all apes - and all
monkeys too - not only to stand upright but to walk upright. They do it when
they wade through water. Five or six other unexplained biological
characteristics unique to our species are most readily accounted for by positing
a hominid ancestor with a waterside habitat. Yet in the professional journals
specialising in evolution, the academic taboo against any serious debate on this
idea has remained in force, unspoken but absolute, for almost fifty years.
The traditional savannah theory had to be abandoned in 1995. A few brave souls have skirted around the abhorrence of the word “aquatic” by speculating about a “riparian” habitat. They’ll get there in the end, but why is it taking so long?