Crouched on the ground, workers carefully removed layers of sediment with brushes, straws and spatulas, revealing irregular traces of a lost world.
“Vertebrae,” explained Rubén Manzanilla López, project supervisor, pointing to a row of large bones rising from the floor. “And there is a pelvis.”
In recent months, the airport’s construction site, 30 miles north of Mexico City, has yielded an immense hideout of bones from one of the best-known creatures in prehistory – the giant extinct relatives of modern elephants.
Excavations have revealed the remains of more than 100 males, females and calves, marking one of the greatest discoveries of its kind in the Americas.
“I think it will be very significant,” said Dr. Emily L. Lindsey, assistant curator and director of excavations at the La Brea Tar Pits Museum and Museum in Los Angeles. “These super large accumulations of remains are not so common and represent a real scientific resource.”
The species found here are the Colombian mammoth, which had long, curved prey and snaked across a wide range from present-day southern Canada to Central America.
A gigantic Colombian scene at the lake pit at La Brea Tar Pits in Los Angeles.
(Mario de Lopez / Los Angeles County Natural History Museums)
The species – about 6 meters tall and weighing at least 10 tons, slightly larger than today’s African elephant – did not have the dense hair of its smaller, contemporary cousin, the woolly mammoth, which favored colder climates more north in the Americas and Eurasia.
Scientists say that herds of pachyderms roam for millennia across the Mexico valley, now a highly polluted and traffic-clogged megacity that is home to some 22 million people.
In prehistoric times, high-altitude pastures, mild weather and ample fresh water – the area was home to five large lakes – were a haven for vegetarian giants.
The animals coexisted with camels, horses and other so-called megafaunas, in addition to paleoamericans, the first humans in the region.
Herds of mammoths thrived deeply in the late Pleistocene era – which ended 11,700 years ago – along the shores of Lake Xaltocan, which dried up decades ago and is now part of a semi-rural suburb that includes the military base of Saint Lucia.
The prehistoric treasure was discovered at the base when the building opened last year at a new civilian airport, a priority project of President Andrés Manuel López Obrador.
Scientists say the animals probably got stuck in the mud of the old lake, failed to crawl out of the mud and succumbed to starvation or exhaustion. Kidnapping animals, and possibly primitive humans, probably consumed their corpses.
Over the ages, its bones were scattered, but were preserved in the land when the lake receded.
Last year, in another location, 15 kilometers from the city of Tultepec, researchers found the remains of 14 mammoths in trenches that they believe were dug by hunters to trap the animals.
Evidence suggests that nomads used torches and sticks to force beasts into cavities 2 meters deep. Once the animals perished, the first Americans slaughtered the carcasses with tools probably created from mammoth bones.
Then they reveled in the meat, apparently tasting tongues that weighed 25 pounds.
“There are traces of mammoths buried here,” said Manzanilla, chief archaeologist at the airport, where dozens of workers in orange helmets and vests scraped the land. “We always knew there were mammoths here, but we never expected to find that many.”
Its magnificent bones have long been myths, inspiring legends among indigenous cultures, as well as creating superstitions among Spanish conquistadors who arrived in the 16th century.
In his seminal account, “The conquest of New Spain”, Bernal Díaz del Castillo narrated how the mysterious remains resonated in the oral history of central Mexico’s Tlaxcalan civilization.
He wrote that the Tlaxcalan people told Spaniards stories about an evil race of “very tall men and women with huge bones [who] once dwelt among them ”and, as evidence, produced a sample of colossal bones, apparently of gigantic origin, including a leg bone as tall as man.
“We were all surprised by the sight of these bones and were sure that there must be giants in that land,” wrote Díaz.
Hernán Cortés, who led the Spanish conquest of the Aztec Empire, ordered a prodigious leg bone to be sent back to Spain, wrote Díaz, “for His Majesty to see.”
In modern times, workers who dug Mexico City’s subway in the 1970s also dug up mammoth bones. Some remain on display in a glass case at the Metro’s Talismán station, which features the stylized image of a mammoth as its logo.
A Colombian mammoth on display at the George C. Page Museum, La Brea Tar Pits.
(Mario de Lopez / Los Angeles County Natural History Museums)
The Colombian mammoth disappeared at the end of the last ice age. But recent research suggests that a population of woolly mammoths remained in the Arctic on what is now Russia’s Wrangel Island until the end of 2000 BC, meaning that some were still crawling when the first Egyptian pyramids were erected.
It is unclear what killed the mammoths and other megafauna. Some speculate about a calamitous meteorite attack. But experts tend to believe it was a lethal combination of habitat loss due to climate change, as glaciers receded and human depredation.
“We assume there have been terrible droughts,” said Manzanilla. “Perhaps conditions have changed, there has been little rain and, without the rain, there was no grass or food.”
Excavations at the airport site also revealed the bones of lone American camels, horses, bison and fish – along with a partial bear claw or big cat.
Mexican authorities have ambitious plans to continue excavating, preserving and studying mammoth bones, which will be housed in a museum at the new airport. The exhibition would trace the evolution of the site, from a zoo from the end of the Pleistocene, home to several pre-Columbian cultures, until its colonial incarnation, when the area housed a Jesuit foundation before the crown expelled the Catholic order from Mexico in 1767.
Authorities say excavations have not subsided the construction of a terminal building and other facilities at the new airport, scheduled to open in 2022.
The findings here represent a rare opportunity to “recover more than 20,000 years of history,” said Joaquín Arroyo Cabrales, a paleontologist who works on the project. “And perhaps better understand the causes of extinction … and the possible human interactions with these animals.”
Cecilia Sánchez, at the Times Mexico office, contributed to this report.