Introduction
In ancient Mesoamerica, human cannibalism served as an institution to the flourishing Aztec civilization. To the Aztecs, the consumption of human flesh was the ultimate exotic culinary experience. Most human flesh was to be consumed only by emperors, nobles, and high ranking soldiers. During a famous sacrifice, figures going up to 80,400 sacrificed and consumed in a single day. Woodrow Borah, a leading authority on the demography of Mexico estimated that during the fifteenth century, 250,000 people were sacrificed annually (Harner). Five centuries later, the complexities of human sacrifice and cannibalism are still disputed. While evaluating the factors behind institutionalized cannibalism of the Aztecs, it is essential to look at the ecological factors in the Pre-Columbian era most importantly, population density and pressure, famine risk and food shortage, and agriculture.

 Population Density and Pressure
           

Through the assessing of ecological stress that could have pushed Aztecs into their cannibalistic practice, it is essential to look at the role of population density and pressure. In, “The Enigma of Human Sacrifice”, anthropologist Michael Harner who taught at the University of California as, Berkley as an associate director of the Lowie Museum of Anthropology and acted as a visiting professor Yale and Colombia University, proposed an ecological hypothesis to explain Aztec human sacrifice. This 1977 journal article, indicates that rising early civilizations suffered from stress of a growing population resulting in a struggle on natural resources (Harner). Struggles such as, reduction of food availability and a disruption on ecological equilibriums of their environment. Michael Winkelman, an Associate Professor in the School of Human Evolution and Social Change at Arizona State University and former Head of Sociocultural Anthropology, evaluated the research of the legitimacy of Harner’s hypothesis by Murdock and Provost (1973), in “Aztec Human Sacrifice: Cross-Cultural of the Ecological Hypothesis.” First, Murdock and Provost evaluate population density in civilizations who practice human sacrifice, ranking them at 5 levels from person per square mile (psm) through 100 psm (Winkelman). Societies who practice human sacrifice correlate with having higher population density, 26+ psm (Winkelman). Also, through assessing population density by food resource measures and the inverse of famine risk and food population, it was found that larger populations had a pressure of limitations on food supply (Winkelman).  Although, there was a correlation between population density and food and resource pressure, there was no correlation that large population density resulted in human sacrifice (Winkelman). Population density put an ecological stressor on the Aztecs but is insufficient to support the ecological hypothesis proposed by Harner.

Famine and Food Shortage
           

A significant factor in ecological strength of a civilization is their availability to food and a steady diet. First hypothesized in “The Enigma of Aztec Sacrifice” by Michael Harner, the lack of protein available for the Aztecs led them to cannibalize each other. Harner wrote that chronic protein shortage in the Aztecs’ environment to consume they had to look for a new abundant food source, humans. In, “Aztec Human Sacrifice: Cross-Cultural of the Ecological Hypothesis” Michael Winkelman evaluated research done to assess famine and food shortage as a factor of institutionalized cannibalism of the Aztecs. Winkleman looks at Oriz de Montellano research who proposes three factors against Harner’s hypothesis, first, the conquering of new lands for agriculture and tribute second, the insignificance of the total human protein available for sacrifice lastly, the presence of human sacrifice during periods where food was abundant, rather than during periods of protein scarcity (Winkelman). This suggest that lack of food supply was not an indicator of human sacrifice. Next, looking at research done by Means of food shortage was present in societies with human sacrifice, the Aztecs were the only civilization with a high risk of famine but the results of the research done by Murdock and Morrow 1970; Ember and Ember 1992 was that the availability of food supplies and resources is not significantly correlated with human sacrifice because the food shortage data is inadequate to indicate certainty of food availability. Jill Leslie Mckeever Furst, noted professor of art history at Moore College of Art and Design in Philadelphia and consulting scholar in the American section of the University of Pennsylvania, wrote in her book “Food for the Gods” describing the cannibalistic diet of the Aztecs. It is said that the consumption of human remains was mainly to consumed only by emperors, nobles, and high ranking soldiers (Furst 2-3). Price (1978) makes the argument that the hypothesis is undermined by the fact the consumption of human flesh was largely consumed by the elite (Winkelman). With There is no significant correlation between food shortage and famine and Aztec human sacrifice and human cannibalism.

Agriculture
           

In the Aztec civilization, agriculture is a main contribter to the complexities when analyzing the institution of human cannibalism. In “The Enigma of Aztec Sacrifice”, Harner writes about the importance of intensifying agriculture production because of the significance of agriculture to create a food supply for the Aztecs (Harner). The Aztecs responded to the need to fill the absence of domestication of herbivorous mammals in the New World in Mesoamerica by using various ingenious agriculture techniques (Harner). Herbert Burhenn, professor at the University of Tennessee, author of “Understanding Aztec Cannibalism”. In his materialist approach perspective in “Understanding Aztec Cannibalism”, Burhenn writes also that cannibalism is due to ecological stress. Harner proposes that a cause for human sacrifice is due to environmental (Harner). In “Aztec Human Sacrifice: Cross-Cultural of the Ecological Hypothesis.”, Winkelman looks at Ember and Ember’s (1992) proxy assessments of environmental circumstances. In this assessment they look at the absence/presence of environmental conditions such as, measures of warfare in relation to resources and land and local political fission. Ember and Ember’s (1992) accounted that measures of internal warfare for land and resources carried a significant correlation to human sacrifice (Winkelman). While looking at political fission, six out of seven societies that practiced human sacrifice lacked political fission including, the Aztecs (Winkelman). Although, the Aztecs had a need for intensification for the intensifying agriculture due to lack of a food supply, this alone is not significant alone in causing human cannibalism because they did not face significant difficulties that would prevent them to achieve a stable agriculture other than, warfare.

Conclusion
Five centuries later the reason behind the prevalence of institution of cannibalism in the Aztec civilization is still debated among researcher. To this day, there is still no answer but it cannot be disputed that ecological factors should be a part of any debate to settle this dispute. Famine and food shortage, population density, and agricultural all play a part in causing stress to a society. A chance famine and food shortage was prevalent in the Aztec civilization but was not a contributor to cannibalism. Evidence in this can be seen through the consumers of humans who were mainly the elite had the the most access to means of food and protein. Population density is present in civilizations that practice human cannibalism such as, the Aztecs but researchers found that this is a correlation it is not a cause for the practice of human cannibalism among societies. Although the Aztecs has a desperate need to intensify their agriculture, their agricultural ability was not threatened to cause them severe harm where they would have a food shortage. It can be concluded that ecological factors were not a cause to human cannibalism but rather, the cause being religious beliefs of the Aztecs.