Deer teeth unveil climate mystery of the Mayans

Though causes of the civilizational collapse that took place in the Maya lowlands of southeastern Mexico and Central America during the Terminal Classic Period (1200 – 900 before present) remain uncertain, changing precipitation patterns have long been suspected.

Now, a new study from the University of Georgia and the Florida Museum of Natural History establishes fossilized white-tailed deer teeth as part of the climate record, a reliable proxy for tracking rainfall amount and seasonality at La Joyanca, a pre-Columbian Maya archaeological site in the Petén department of northern Guatemala that was occupied for more than a millennium. 

The study in the journal Isotopes in Environmental and Health Studiesfor the first time analyzed isotopes (variants of a certain chemical element that differ in neutron number) in teeth recovered from La Joyanca.

While most of the available indicators record regional trends, local indicators allow researchers to explore the extent and consequences of climatic events at the community scale. Fossils from archaeological sites are an example of local indicators that have shown great potential to improve our understanding of events that occur in Mayan archaeological sites.

“As we face the global consequences of climate change, we can learn a lot from the experiences that ancient cultures, such as the Maya, faced due to climatic events hundreds of years ago,” said María José Rivera Araya, who authored the study while a graduate Fulbright student in the department of geography at UGA. “Whereas we already know that several regions in the Maya area were dramatically and negatively impacted by extreme droughts, our study contributes to the development of more detailed, community-level records that will help us understand how previous societies responded to climatic events, and how these events impacted their economies, politics and social structure.” 

The study utilized stable isotope analysis, a leading-edge method still developing in its applications in archaeology and other fields, to help scale the understanding of the impacts of large-scale climate and environmental change. 

“We may have evidence for climate change at global levels, or regional ones (as the paper discusses), but how is that reflected locally, at the level of an archaeological site?” said UGA assistant professor and co-author Suzanne Pilaar Birch. “And if we can detect a local climate signal, how does that compare to the archaeological evidence for changes in that society —in this case, the overall widespread decline of the Maya, often attributed to drought.”

A previous study authored by Rivera also used oxygen isotope signals in modern white-tailed deer teeth from Georgia to better understand the relationship between the isotopic values and various climate factors.

The full study is available at https://www.tandfonline.com/doi/full/10.1080/10256016.2019.1636047

Image: Figure 1 from the study - Map of Yucatan Peninsula. Location of La Joyanca and other sites mentioned in the text.