The mammoth traps at Tultepec changed how archaeologists think about hunting in Mexico. In 2019, archaeologists working at Tultepec, north of Mexico City, exposed two pits with walls dropping almost vertically through the old lake-bed clay. They were not shallow muddy hollows where an animal happened to get stuck. The shape suggested that people had made them.
The pits were about 25 metres across and 1.7 metres deep. Inside and around them, the excavation team recovered 824 bones belonging to at least 14 Columbian mammoths (Mammuthus columbi). That is the kind of evidence that makes a simple question feel enormous: how do you persuade an animal weighing several tonnes to walk toward a hole in the ground?
What was found at Tultepec?
The site, known as Tultepec II, lies in the basin once occupied by Lake Xaltocan. About 15,000 years ago, the lake had retreated enough to expose broad, wet plains. Mammoths could feed around the water and move along the edge of the basin. For people living nearby, that landscape offered a predictable place to watch large animals gather.
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According to the Instituto Nacional de Antropología e Historia (INAH) and the National Autonomous University of Mexico (UNAM), the two pits had walls close to 90 degrees. The excavators recorded skulls, jaws, vertebrae, ribs, shoulder blades, long bones and smaller fragments. Most of the bones were no longer connected in the order they had held in the body, which fits a site where animals were butchered and their remains moved around.
The count also needs a little care. The 824 bones and 14 mammoths refer to the Tultepec II excavation described by the archaeological team. The wider region, including the separate Santa Lucía airport salvage project, has produced many more mammoth remains. Those projects belong to the same ancient lake basin, but they are not one giant pit and should not be folded into a single total.
How could the trap have worked?
The excavated walls give us the strongest clue. A mammoth that stepped into a deep, narrow-sided pit would have struggled to climb out. Its weight would have worked against it, while the clay sides offered little purchase. People could then approach from the edge with spears or other tools rather than standing in front of a moving animal.
That is the basic mechanical advantage. The difficult part is getting the mammoth into the pit.
INAH archaeologist Luis Córdoba Barradas proposed that hunters could drive an animal away from the herd with fire, branches and noise. A group of 20 or 30 people might funnel it toward a prepared depression, separate one animal from the group and keep it moving until the ground gave way beneath its feet. The pits therefore make most sense as part of a coordinated strategy rather than as isolated holes waiting for luck.
The excavation does not preserve a film of the hunt. It preserves the ground after the event: cut earth, buried bones, ash and lake sediments. That is why the wording matters. Archaeologists can identify a human-made trap and reconstruct a plausible sequence, while the exact movements of the hunters remain an interpretation built from several clues.
The lake helped preserve the scene
The old lake is more than background scenery. Fine clay, volcanic ash and waterlogged sediments helped bury parts of the excavation. INAH reports that layers of ash and bentonite—clay associated with the lake bed—sit among and above some of the bones. Those layers provide a relative timeline and place the activity near the end of the Pleistocene, when the basin was changing quickly.
The landscape was also unstable. Drying and falling lake levels could expose new ground, while eruptions and ashfall altered routes used by animals and people. A trap dug beside a shrinking lake would have been an investment in a particular landscape: useful while mammoths continued to pass through, less useful once water, vegetation or migration routes changed.
The mammoths themselves were not all alike. The Tultepec assemblage includes animals of different ages and both sexes. That is consistent with repeated encounters with a herd or with several hunting events over time. It does not, on its own, tell us whether every animal died in a trap. Some bones may have been carried, disturbed or exposed by later activity.
What happened after the animals died?
The bones show an efficient use of the carcasses. INAH’s field account describes cut marks on ribs and shoulder blades, worn bone fragments that may have served as tools, and skulls found inverted. The arrangement suggests that people removed meat, organs, hide and useful material rather than leaving the animals where they fell.
One group of bones was arranged in an unusual way around a skull, with shoulder blades placed together and a vertebra set beneath the head. The excavators have considered whether this was more than practical butchery. Perhaps it was a deliberate arrangement. Perhaps the movements of later work created a pattern that looks intentional. The evidence invites the question, but it does not settle the meaning of the gesture.
That tension is what makes Tultepec so valuable. The site is not simply a pile of mammoth bones. It records a chain of decisions: where to dig, how to move an animal, which parts to remove first and how to use a carcass that provided food, hide, bone and perhaps social meaning.
The broader record shows that people in the region repeatedly worked with mammoth remains. Curiosmos has also looked at a much older structure made from mammoth bones, a different kind of evidence for how Ice Age communities used what was around them. Tultepec adds another possibility: mammoths were not only found dead in marshes; in at least some places, people may have shaped the landscape to catch them.
What do the pits actually prove?
They provide strong evidence for deliberate earthworks associated with mammoth remains. They show that hunters in the Mexico City basin understood animal movement and could organise labour on a scale larger than a single person or family. They also show that a kill site can preserve practical knowledge that written sources never recorded.
They do not reveal every weapon used, the precise size of each hunting party or whether a ritual accompanied every carcass. Nor do the pits prove that mammoth hunting was the only way people obtained meat. The same lake margins could offer fish, birds, smaller game, plants and naturally trapped animals.
Still, two deep cuts through ancient lake clay are difficult to ignore. They turn a familiar Ice Age scene—a mammoth moving across a wet plain—into a problem of planning, timing and cooperation. Near modern Mexico City, the ground itself remembers the moment when hunters tried to make an enormous animal take one wrong step.
