But deep in the jungles of Belize, under the dry refuge of two rock shelters, the skeletons of people who died as many as 9,600 years ago have been exceptionally well preserved. Their bones offer a rare glimpse into the region’s ancient genetic history, which is largely unknown.
The tropics are a paradise for everyone but a skeleton. Humidity keeps rainforests green but does little to preserve bodies, leading to a dearth of ancient skeletal remains in Neotropical regions such as Central America.
But deep in the jungles of Belize, under the dry refuge of two rock shelters, the skeletons of people who died as many as 9,600 years ago have been exceptionally well preserved. Their bones offer a rare glimpse into the region’s ancient genetic history, which is largely unknown.
A group of scientists has now extracted these ancient people’s DNA, offering new insight into the genetic history of people in the Maya region. The paper was published recently in the journal Nature Communications. The researchers identified a previously unknown mass migration from the south more than 5,600 years ago that preceded the advent of intensive maize farming in the region. This migration of people, who are most closely related to present-day speakers of the Chibchan languages, contributed more than 50 pc of the ancestry of Mayan-speaking peoples now.
Lisa Lucero, an anthropologist at the University of Illinois at Urbana-Champaign, said the new results “have the potential to revise and rewrite the early history of the First Americans.”
Xavier Roca-Rada, a doctoral student at the University of Adelaide, said the results “fill a gap between the oldest previously studied individuals from the Maya region and the time before the settling of Mesoamerica.”
The new paper emerged from ongoing excavations led by the authors Keith Prufer, an environmental archaeologist at the University of New Mexico, and Douglas Kennett, an archaeologist at the University of California, Santa Barbara. The researchers have been excavating two rock shelters in the Bladen Nature Reserve, a remote and protected area of Belize that kept the sites, which were used as cemeteries, undisturbed for thousands of years. “People just kept going back to them over and over and over again and burying the dead,” Dr Prufer said.
The shelters were also occupied by the living, who made tools and cooked, evidenced by the buried bones of armadillos, deer and a type of rodent called a paca, Dr Prufer said. The very bottom of the excavated pit held a piece of a giant sloth, which may have even predated human occupation of the shelter, he said.
The excavations also revealed a secret, formerly slimy layer of protection underground. Around 5,000 to 6,000 years ago, before the classic period of the Maya, people harvested tiny Pachychilus snails for food. “They would boil them and lop off the end of the shell and eat the flesh out of them,” Dr Prufer said. Whoever inhabited these shelters feasted on these snails, and their discarded shells shielded bodies buried below. “This layer of snails actually protected the lower burials from the Maya digging through them,” he said.
Dr. Kennett and Dr. Prufer study these early burials to understand how the region transitioned from hunting and gathering to the development of intensive agriculture of maize, chili peppers and manioc (also called cassava). In a 2020 paper, they described evidence of maize consumption in the bones of individuals who lived 4,000 to 4,700 years ago.
