How modern life is transforming the human skeleton
From the emergence of a spiky growth at the back of some people’s skulls to the enigmatic finding that our elbows are getting narrower, our bones are changing in surprising ways
It all started with a goat. The unfortunate animal was born in the Netherlands in the spring of 1939 – and his prospects did not look good. On the left side of his body, a bare patch of fur marked the spot where his front leg should have been. On the right, his front leg was so deformed, it was more of a stump with a hoof. Walking on all fours was going to be, let’s say, problematic.
But when he was three months old, the little goat was adopted by a veterinary institute and moved to a grassy field. There he quickly improvised his own peculiar style of getting around. Pushing his back feet forwards, he would draw himself up until he was standing half-upright on his hind legs, and jump. The end result was somewhere between the hop of a kangaroo and a hare, though presumably not quite as majestic.
Sadly the plucky goat was involved in an accident soon after his first birthday, and he died. But there was one final surprise lurking in his skeleton.
For centuries, scientists had thought that our bones were fixed – that they grow in a predictable way, according to instructions inherited from our parents. But when a Dutch anatomist investigated the goat’s skeleton, they found that he had begun to adapt. The bones in his hips and legs were thicker than you would expect, while the ones in his ankles had been stretched out. Finally his toes and hips were abnormally angled, to accommodate a more upright posture. The goat’s frame had started to look a lot like those of animals which hop.
Today it’s an established fact that our skeletons are surprisingly malleable. The pure white remains displayed in museums may seem solid and inert, but the bones beneath our flesh are very much alive – they’re actually pink with blood vessels – and they’re constantly being broken down and rebuilt. So although each person’s skeleton develops according to a rough template set out in their DNA, it is then tailored to accommodate the unique stresses of their life.
This has led to a discipline known as “osteobiography" – literally “the biography of bones” – which involves looking at a skeleton to find out how its owner lived. It relies on the fact that certain activities, such as walking on two legs, leave a predictable signature behind, such as sturdier hip bones.
And from the discovery of a curious spiky growth on the back of many people’s skulls to the realisation that our jaws are getting smaller, to the enigmatic finding that German youths currently have narrower elbows than ever before, it’s clear that modern life is having an impact on our bones.
For an example of how osteobiography works, take the mystery of the “strong men” of Guam and the Mariana Islands. It began with the discovery of a male skeleton on the island of Tinian, which lies 1,600 miles (2,560km) east of the Philippines in the Pacific Ocean, in 1924. The remains were dated to the 16th or 17th Century, and they were positively gigantic. The man’s skull, arm bones, collarbones, and the bones of his lower legs suggested that he had been immensely strong and unusually tall.
The finding slotted in nicely with local legends of enormous ancient rulers, who had been capable of truly heroic physical feats. Archaeologists called him Taotao Tagga – “man of Tagga” – after the island’s famous mythological chief Taga, who was renowned for his super-human strength.
As other graves were discovered, it became clear that the first skeleton was no anomaly; in fact as well as fiction, Tinian and the surrounding islands had been home to a race of extraordinarily brawny men. But where had they got their strength from?
As it happens, the strong men’s remains were often found lying next to the answer. In the case of Taga, he was buried amongst 12 imposing carved stone pillars, which would originally have supported his house. Meanwhile, a closer inspection of his bones and others has revealed that they have similar features to those from the Tonga archipelago in the South Pacific, where people do a lot of stone working and building with massive rocks.
The largest such house on the island had pillars that were 16ft (5m) high and weighed nearly 13 tonnes each – about as much as two full-grown African elephants. This was no mysterious race of mu