I’ll be a monkey’s cousin!

On seeing a human, Bo-bo found it hard to believe that they were just as evolved as chimpanzees. Illustrated by Mike McRae

‘Is it through your grandmother or your grandfather that you consider yourself descended from a monkey?’ the bishop ‘Soapy’ Sam Wilberforce once asked the naturalist Thomas Huxley during a rather heated debate on the topic of evolution.
Following Darwin’s book ‘On the Origin of Species’, a number of people mistakenly believed that the ancestors of modern humans were apes and monkeys. Of course, this makes as much sense as saying your cousins are also your great, great grandparents. Darwin’s argument was that humans and primates are more like very distant cousins – we both share a common ancestor.
Like humans, our closest living relative - the chimpanzee - has also evolved quite a bit over the past few million years. But finding fossils that describe precisely what our shared ancestor may have looked like is a little tricky.
A recent find has come quite close, and has palaeontologists rather excited. At four and a half million years old, Ardipithecus ramidus (Ardi for short) would have walked the Earth only a few hundred thousand years after the ancestors of chimpanzees and humans went their separate ways.
Ardi’s bones tell an interesting tale. It seems this species walked upright, just as we do, yet had hands and feet that were capable of grasping branches with ease. Importantly, their pointy canine teeth were smaller than those of other apes, indicating a change in how often males fought one another. This tells us a little about their behaviour.
Such clues hint at what a common ancestor of humans and chimpanzees might have looked like. While it’s tempting to picture them with rather chimp-ish characteristics, it seems nothing could be further from the truth.
It’s easy to consider the great apes as ‘primitive’ or ‘unevolved humans’. Using Ardi’s bones to give us a snapshot of our family album, it’s clear that chimpanzees have come just as far in five million years as we humans.