To help save a critically endangered Central American species of river turtle, conservationists examined the gene pools of three highly isolated populations. What they discovered is a surprising legacy of the ancient Mayan civilization.
Smithsonian scientists examined 238 wild turtles, each of which came from one of 15 locations in three separate river basins. These three habitats are completely and utterly separated from each other, not just by long distances but by huge mountain ranges that would be completely impossible for the turtles to cross. Under those circumstances, one would assume the turtles would also be isolated from each other genetically.
Instead, the researchers found that the populations were all jumbled together, making it a virtual certainty that they had been in close contact repeatedly in the relatively recent past. And the only way that could happen is if humans are the ones doing the mixing and matching. We know that these turtles were used by the Mayans for food, trade, and religious purposes for many centuries, and these turtles were moved around considerably until they were ready to be used.
In their paper, the scientists explain just how far back this turtle tampering goes:
"For centuries, this species has been part of the diet of the Mayans and other indigenous people who lived in its historic distribution range. [The river turtle] was a very important source of animal protein for the ancient Mayans of the Peten (Preclassic period 800-400 B.C.)...And it is possible that these turtles were part of the diet of the Olmec culture more than 3,000 years ago."
The genetic data already reveals how crucial humans were in shaping the future of these turtles, and examining archaeological sites reveals how important the turtles were to humans. The remains of one particular river turtle were found in the pre-Mayan city-state of Teotihuacan, a site some 186 miles from its known range. Another site features a sculpture of a turtle that was only found 217 miles away.
Via Conservation Genetics. Image by Gracia González-Porter.