17 January 2004
Why did Iron Age man go off fish?
Fragments of femur excavated from an Iron Age burial site in east Yorkshire (England) have been analyzed by the department of archaeological sciences at Bradford University. For scientists, bones such as these contain a key piece of information about ancient societies: what people ate. Remarkably, bones retain a chemical signature of what went into making them in the first place: what it was in the diet that provided the raw materials for the bone to grow. As we first reported last September, by examining bone in this way, the Bradford researchers, led by Dr Mike Richards, have made a number of significant discoveries. The most intriguing is that around 6,000 years ago Stone Age man in Britain seems suddenly to have stopped eating fish and shellfish. This dietary restriction persisted for the better part of 4,000 years, until the Romans arrived.
Mandy Jay has been examining the diet of people buried at the largest Iron Age cemetery in Britain at Wetwang, on the Yorkshire Wolds. The cemetery dates from the 3rd or 4th century BCE, and contains around 450 people. "The cemetery was used over a period of about 200 years, and there is a very particular pattern to the burials," says Jay. "There are five chariot burials, where bodies have been buried with chariots. It is assumed that these were the highest-status individuals. There are remains of bodies that were buried under specially constructed mounds, or barrows, which presumably was also indicative of status, and finally bodies buried in the ditches surrounding the barrows - suspected to be the lower status."
"The question I wanted to ask is whether we could see a difference in diet depending on the assumed status of the individuals," says Jay. Following isotope-ratio analysis on almost 50 samples, Jay has concluded that there is no difference between the three groups in terms of the source of their protein. "All of the samples showed quite a lot of animal protein in the diet," she says. The proportion of animal and plant protein remained similar throughout the period that the cemetery was being used. This suggests that the community was highly economically stable over this time, with the same farming practices persisting for two centuries. "The other thing that we can say with some confidence is that there is no evidence of any marine protein having been consumed," says Jay. "Things like fish and shellfish were absent from the diet." This fits in with a recent finding by Dr Richards that people simply did not eat seafood at this point in history.
"We know that about 6,000 years ago, during the Neolithic period, there was a revolution in the way people lived. People stopped being nomadic hunter-gatherers and started to farm animals and crops, and live in villages." said Dr Richards. There were big cultural as well as economic changes at this time. Domesticated animals were brought over from the Continent, and wheat and barley appeared. Pottery began to be made, and elaborate burial monuments started to appear. "From a dietary point, before this time there was only wild food," says Dr Richards. "If you do isotope analysis of bones found at coastal sites, you find evidence of a large amount of marine food in the diet. But after about 4,000 BCE suddenly there is no marine food in the diet. People simply stopped eating fish and shellfish."
The reasons for this are not clear. One school of thought suggests that a shift in climate at that time, causing sea levels to rise, made fishing difficult. Other archaeologists think that the advent of farming made the food resource much more secure - there was no need to harvest wild food. Dr Richards believes that the radical change in diet reflected larger changes in society. "It coincides with the appearance of pottery and of big monuments and new burial practices," he says. "My hunch is that there was a spread of a new kind of belief system, a new way of looking at the world, and a big part of that could have been a change in diet. But it is rare that you see such sudden changes."
Fish seems not to have appeared again on the menu until the Romans arrived, 4,000 years later. The pattern is confirmed in Jay's findings. She has looked at samples of Iron Age bone from two coastal sites, in Cornwall and East Lothian. These, too, are devoid of any evidence of a marine diet. "We know that the technology for fishing existed and you would have thought that a ready source of food would be exploited. It might have been that seafood in some way became taboo. Even now there are dietary taboos - for example we balk at the thought of eating horsemeat or dog, but these are eaten in some societies. In fact we know that people in the Iron Age did eat dogs and horses." says Jay.
Source: The Independent (14 January 2004)