Neanderthals again, and why they died out. Of course, perhaps they didn't die out, and just mingled themselves into non-existence with us. I suspect we find that idea a bit distasteful, like discovering that we have the servants in our genes. Much better that they died of lacking something we most value that we had more and better of. The latest theory is that their eyes were too big. They've measured the orbits in the skulls and yes, they are larger than Homo sapiens skulls. So they saw better in the dark, but more of their brains were devoted to interpreting the messages from their great big eyes. Eyes bigger than their cerebral cortex. But Homo sapiens with their smaller, less efficient eyes, had room in their brain pan to develop their cerebral cortexes and use them for social networking and therefore learning and making the great cultural leap forward. Oh dear, yes, 'social networking' is the phrase they use. In my anthropological day, it was just called 'socialising'. But our clever brains are too smart to settle for mere socialising when they can come up with social networking. Evolution. There you have it in a nutshell, or a network.

Chris Stringer says the big eyes idea sounds like a proper theory. And he's the man. A sort of palaeontological hero. He did his anthropology at University College London, and so, later, did I, as a mature student in the early 1980s. I gave up in the third year and wrote my first novel, he didn't and is now Head of Human Origins at the Natural History Museum. But back in my day there was another theory about the disappearance of the Neanderthals. For the life of me I can't remember whose theory it was, but I'm pretty sure I didn't make it up, because discovering it pleased me so much. Neanderthals, it went, died out because the females, like Homo sapiens females, had small pelvic girdles and their infants had large heads. Enough of them failed to get born for them to die out as a group, so the smaller brained Homo sapiens, born too early with unfinished, flexible skulls, had their chance. Which means, I was delighted to discover, that the big-brained Neanderthals died out because they were too clever. Which is where the phrase 'You're too clever by half' came from. Or if it didn’t, it should have.

I doubt that Chris Stringer would endorse the theory, but to me it has the ring of truth. What survives, just like popular ideas, prize winners, popes and cabinet ministers, is a compromise, a trade-off, the acceptable second best. The really smart big-brained ones couldn't make it through, so the planet was left with us. Smaller-brained, omnivorous, adaptable, brilliantly opportunistic, fitting into any available niche. Scavengers, really, but scavengers who are really pleased with ourselves.

But no, I'm going to have to accept that Neanderthal eyes were too big for their own good, and we Homo sapiens, as we are pleased to call ourselves, turn out, once again, to be the best possible hominid for the best of all possible worlds.