Gosh! Did our brains really shrink?

Keith Hudson

Full marks to Richard and Adam Ferguson!  They stayed their father’s hand — or, rather, his foot a few weeks ago — when his spade struck a bone when digging a deep hole in their garden to make a pond.  Rescuing the bone . . . and then finding others in the finest traditions of the professional archaeologist, they carefully extracted what turned out to be a whole wolf-ful collection of bones.  A photo in this morning’s paper shows the reconstructed skeleton of a wolf that, according Manchester University’s DNA people, was alive about 20,000 years ago.

As a companion piece to the photo, there’s another item about some research by Dr Love Dalen of the Swedish Musuem of Natural History and Pontus Skoglund of Harvard Medical Schools which is now showing that the domestication of wolves into dogs — originally as hunting associates but also as night watchmen around their camp fires — began, not 20,000 years ago as was thought until recently, but 40,000 years ago.

This is yet another instance of dates being pushed further and further back into the past.  Other research recently from fossil bones in Somalia show that stone tools were used by our predecessors many hundreds of thousands of years before our own species mutated.  Dates of the trading of sea-shell necklacess and other desirable artefacts have been successively pushed back from 20,000 years ago to the latest discovery dated 100,000 years ago. My guess is that trading was one of the very first activities that started at the very dawn of man some 200,000 years ago (although that date, too, might well be pushed back further!).

What was thought to be man’s uniqueness, particularly in Victorian times when even well-educated people thought that we might have been a very special creation — particularly their own middle-class at that time — is becoming blurred.  And it’s not just going backwards in time — such as discovering earlier dates when man began to draw animals or were engaged in trade — but sideways, too.

We are increasingly discovering that some animals such as crows can solve problems that even children can’t, or that blackbirds enjoy sledging down snow on a tin roof just as we like to do in the Cairngorms, or that rats save one another from drowning, or that porpoises act as midwives to mothers giving birth or that several other species besides ourselves are born with delicate notions of fair play, or justice, when considering sharing food with others.  The boundaries between us and other species or with our own immediate predecessaors are becomin increasingly hazy with almost every new fossil discovery or experiment.

Just how unique are we?  Pretty unique, but certainly not totally so.  And what about one amazing similarity between wolves and us? When wolves became domesticated into dogs — no doubt over several generations (at least a couple of dozen, as was needed when Dmitri Belyaev tamed the viciously aggressive Siberian fox into a children’s pet) — some of the many genetic changes that occurred produced a smaller brain and floppy ears.

Well  . .  perhaps not floppy ears in our case! — they’re rather hideous appendages that even hairstylists can do nothing about, except cover them up —  but certainly brain shrinkage.  In the generations that elapsed between the first ‘wild’ hunter-gatherers who, quite independently, started turning to millet farming in northern China, or rice planting in Indonesia, or wheat growing in Mesopotamia, or oats in Peru — all at around 8,000 to 10,000 years ago —  our brains became about 10% smaller.

This is what happens to Siberian foxes as also many other wild animals when they become domesticated.  To those of you who are English: Undoubtedly you will have noticed that the heads of semi-wild Exmoor ponies who, thankfully, are still allowed to roam at large, are still quite large compared with those of racehorses or those wonderful shire horses pulling ploughs (we still do a little of this in England!).

Incidentally, while on the subject of the genetics of horses, did you know that modern racehorses who are supposed to be the products of the most exquisitely skilled horse breeders are nothing of the sort?  They are horses that are on the edge of species breakdown.  The absurd prices that are paid for some progeny are just other examples of rich men’s status follies.  Racehorses have been in-bred so much for speed that they now throw up more congenital disasters than any other species confined to our loving care and attention.  Modern racehorses that actually survive to have a saddle put on them are racing no faster than they were a century ago.  Take pot-luck with almost any foal that can stand on four legs and you might have a future Derby winner.

Back to us, yes, our brains declined in volume at around 8,000 to 10,000 years ago when we self-domesticated ourselves to become farmers.  No one knows why, or quite what happened to the structure of our brains, at that time.  Bruce Lahn, prof of genetics at Chicago University and probably the world’s mostly eminent geneticist has discovered that the MCPH1 brain gene mutated significantly about then — albeit in people outside Africa — but quite what this new mutation does, no-one as yet has elucidated.  As most of our brain is taken up with grey matter — thick insulated trunk lines between neurons — and also fluid-filled spaces, then our processing capacity, or intelligence, might not have changed at all.  This has yet to be elucidated.

As I end this piece and find myself deciding quite what to write by way of a suitable conclusion, I have just come across another new, interesting story which appeared today.  I’ll write about that next and this essay will serve as a very useful introduction to that one.

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