a tropical lowland environment under increasing population pressure. Deforestation, the invasion of grasses, soil depletion, and erosion cut into productivity, ultimately causing nutrition and health to deteriorate. People became more vulnerable to infectious and parasitic diseases, especially diarrhea, and the dense settlement helped these diseases to spread. This led to dispersal and depopulation.
At the time of the conquest the Spanish did observe that slash-and- burn maize fields were the only form of subsistence in the severely depopulated Maya region. But archaeologists now know that at the peak of population, the Maya were practicing more varied, sophisticated, and intensive farming. They built raised fields in wetlands and constructed terraces to manage water and soil fertility. This does not mean that the Maya may not still have degraded the environment, although it does give us a new respect for their agricultural knowledge.
The “dirt” archaeologists who have uncovered house platforms and pots are not The only anthropologists who contribute to an understanding of the population and environment of the Maya. Bioarchaeologists study the bones and teeth in ancient burials. The Maya buried their dead under the floors of individual houses. With no big cemeteries to give large samples of skeletons, it is a somewhat slow process to build up a picture of changing health conditions across time, place, and social status. Some of this skeletal evidence does give support to the ecological hypothesis. Comparing the length of leg bones, for example, suggests that, on average, men were shorter in later time periods. As population grew, food may have become scarce, stunting growth.
Defects in the enamel of children's teeth also support the conclusion that Mayan health deteriorated over time. The teeth show that children experienced significant nutritional stress around age three, the usual age of weaning. In the Late Classic period at Copan, Rebecca Storey (1992) found that even children buried in a relatively wealthy elite residential group were under nutritional and infectious disease stress.
Few anthropologists find the ecological explanation for the Maya decline by itself fully satisfying, and they are adding a political dimension to their explanations. In the case of Copan, for example, it is clear that the last kings were losing their grip on their kingdom. Privileged people, the nobles, were increasingly powerful and continued to have access to valuable imported goods such as pottery for deposit in their own tombs, even after the construction of royal monuments ceased. The royal power collapsed abruptly, but it is not clear whether the final blow to it came from internal political conflict or external war. There is little indication from trauma to skeletons or the sudden destruction of buildings that there was mass violence at the time of the so-called "collapse." Population remained high for a while after the political crisis and then began to decline.