A Maya priest whips up commoners into a frenzy in Mel Gibson's ï¿½Apacolypto.ï¿½ The movie depicts the death rows of a corrupt and famine racked society. It's the latest and many say largely incorrect depiction of the divine mystery of the Maya people. ï¿½Probably 90% of them died between 760 and 930. so the question is, how did millions of people vanish from the face of the earth?ï¿½ this Texas archeologist is author of a book on the fate of the Maya. He says the theories fall into two camps. The first holds that something happened to the Maya. The other says the Maya did something to themselves. ï¿½This is the thrown of one of the great kings here,ï¿½ this man takes the view that internal problems caused the Maya collapse. He is an archeology professor at Vanderbilt University. he's giving me a tour of the largest Maya ruin. It's in Guatemala's lowland jungle. Hundreds of colorful species of birds soar above the abandoned ball courts, towering pyramids and ceremonial plazas. The Vanderbilt archeologist, ï¿½And the king would sit down on the jungle mat and a jaguar pelt and there would be servants with fans and maybe a band over here.ï¿½ He says internal conflicts and hostilities among the many Maya kingdoms eventually sapped the civilization's strength, ï¿½You have too many princes and they all have a legitimate claim to the throne and they fight for the throne. And you also have all this need for more palaces, more temples, more rituals, more jade.ï¿½ By the mid-8th century AD the Maya civilization had collapsed under its own weight, says that archeologist. But in the past decade, a theory of the other sort has been gaining ground. It says the Maya broke up under a series of scorching droughts. The author from earlier is its chief proponent, ï¿½the Maya had a term for severe, devastating drought, and that term was ï¿½when the deer died.ï¿½ Well I have certainly seen when the deer died, I have lived through it.ï¿½ The author came of age in Texas in the 1950s during a withering drought there. As a child he accompanied his father to failing farms where animals were literally dying of thirst. Later as a graduate student, he wondered if the same forces of nature might have caused the Maya collapse, ï¿½When I first proposed this in my PhD dissertation back in the early 90s there wasn't any evidence.ï¿½ but climate researchers have since supplied the evidence, beginning with a study lead by this man. I met up with the University of Florida geologist on a barge on a Guatemalan lake. His team is using a drill rig to sample sediments under the lake floor. He says, ï¿½This floor which is the fourth floor we've taken, it consists of this grey clay produced during the erosion that was caused by the deforestation by the Maya civilization.ï¿½ By examining similar muck in Mexico, his team showed that the Maya suffered a punishing natural disaster, ï¿½in 1995 we published a paper that we think really provided the first physical evidence for significant drought that occurred during the period between 800 and 1000 AD.ï¿½ Then a team studying ocean sediments showed that the drought was not a single event but three intense multi-year droughts. The author from earlier says at this point evidence of drought is indisputable, ï¿½So the argument now revolves around what effect did a severe, devastating drought have over Maya society.ï¿½ The debate over what caused the Maya collapse is being followed closely by archeologists studying other parts of the world. They're looking into whether drought explains the decline or disappearance of many ancient civilizations. One new study identifies a series of three droughts in China at the same time as the ones that may have done in the Maya. Its authors speculate that a single, worldwide dry spell may have finished both of the Maya and China's famed Tang Dynasty.