From hunter-gatherer to a fat bloke with bad teeth

The story of human evolution and the search for missing links in the fossil record has been well served by literature and the media. However, the story of human physical change in more recent history, the past 10,000 years, has been given less coverage.

Clark Spencer Larsen sets out to tell how bio-archaeology (normally referred to as osteo-archaeology in Britain) can tell us how the human physical form has been altered by our changing environment and lifestyle in recent history. He does this through a series of case studies that take us through American history from prehistoric hunter-gatherers and early farmers, the contact period with early European settlers and then the pioneer period. As a sub-plot we get Larsen's personal career history, and just about everyone he has ever met gets a name check.

Osteo-archaeology has certainly developed an impressive array of scientific tests that can be used to identify physical and biological stresses that in turn reflect lifestyle. Larsen goes into great detail to explain these methods and show how they can be used. His major theme and concern is the transition from a hunter-gatherer to a farming lifestyle some 10,000 years ago.

Study of skeletons throughout the world has now clearly shown that these humans experienced a deterioration in health as they moved from one lifestyle to the other. This obviously runs contrary to the idea of this move being one of progress and is a major contribution to this very complex and hugely important stage in human development. Simply, domestication meant that many more could be fed, but led to restricted and not particularly healthy diets.

However, osteo-archaeology is also a problematic science. It is reliant on large and good samples of skeletons to work with, and even then it is often difficult to be precise in making the link between observed differences between skeletons and how this might have been influenced by historical change.

We now know that skeletal evidence does suggest early farmers were less healthy than hunter-gatherers, but as Larsen himself remarks: "On balance, most hunter-gatherers were probably just as miserable as most agriculturists."

There are also examples of scientific study doing no more than confirming the obvious. Of the hunter-gatherers of North America, people who had to hunt or collect all their food, he observes: "My immediate impression of the hidden cave bones was that the people represented by them were physically active, and extraordinarily so." Well, I'm sure they were.

As one proceeds through the history of America and encounters one after another collection of people living on the edge and is presented with more and more scientific data to prove as much, one longs for a quirky little fact that has affected the way we look. It finally comes on page 229. We all have bad crooked teeth because thousands of years ago we stopped chewing big pieces of raw meat. The jaw bone that would have supported the necessary muscle has been growing smaller ever since - leaving less room for the teeth. Modern America is full of fat people with tooth braces because 10,000 years ago humans stopped hunting and started farming.

Hedley Swain is head of early London history and collections, Museum of London.