The pictures of Ambam the gorilla standing up on his hind legs and walking, for all the world just like one of us, are quite captivating.
Not only do they serve as a powerful reminder that, after chimpanzees, gorillas are the second closest living relative to humans, but for me they also brought back so many happy memories of my own encounters with these gentle giants of the great ape world.
Nothing, not even David Attenborough, prepares you for the moment you come face-to-face with a wild gorilla for the first time.
It sounds a little like someone repeatedly clearing their throat and apparently lets the gorillas know you’re not a threat. It worked.
Kneeling amid the undergrowth in a non-threatening way, I had the privilege of observing at close quarters a family group of 12, doing what gorillas spend most of their time doing: eating.
About half were adult females, with offspring of various ages including two ‘black-backs’ – the gorilla equivalent of male teenagers.
Presiding over everyone was the patriarch or silverback, so called because of the silver saddle of hair males acquire at full maturity.
He looked at me thoughtfully, almost human-like, with those big, dark eyes, and chomped. Clearly, I was not considered a threat.
For like all great apes, gorillas do regularly walk on their hind legs, helped by the same hip-alignment (it seems to have evolved in species that hang from trees) that eventually made us humans so good at it.
In the wild, gorillas do it in many situations. When I was in the Central African Republic, I learned just how intimidating it is to have a gorilla stand on its hind legs directly in front of you.
A very protective Western lowland silverback that was unused to people stood upright and beat his chest several times before returning to all fours and charging with a roar.
The best response is to lower your gaze and stand your ground. Trust me, that’s very hard. But when I just about managed it, it proved surprisingly effective.
An actual attack on a human by a gorilla is very rare. They are more interested in demonstrations of their power than actually using it in anger.
Walking on our hind legs – bipedal motion, as it’s called – is one of the distinguishing characteristics that makes us humans human, and we’re always impressed by an animal, be it dog, bear or, indeed, gorilla that can mimic it.
But there’s another reason why those pictures of Ambam are so powerful and that’s because, quite unwittingly, he is reproducing that almost mythical moment from evolutionary history when one of our ape-ancestors came down from the trees and walked on its hind legs for the first time.
I vividly remember seeing wild Western lowland gorillas also demonstrating this, as they came out of the safety of the rainforest on to the swampy plain and instantly stood up on their hind legs to survey the exposed ground for dangers.
You see them doing the same when they hear a sudden noise. The silverback does exactly what a human would do — he stands up and looks anxiously around for danger.
But we should be wary, perhaps, of over-emphasising the similarities between humans and gorillas, despite the estimated 95-98 per cent of genetic material the two species share.
You have to go back eight to nine million years to find the common ancestor from which both gorillas and humans evolved, while the split with chimpanzees happened later, some five to six million years ago, which explains why chimps and humans differ in their genetic make-up by just 1 per cent.
