The teeth of some important members of the Maya civilisation were removed and kept in a cave far from their tombs. It may have been done to venerate ancestors or ensure they made it to the underworld.

During the Classic period (AD 250-900), Maya communities lived in cities spread across what is now southern Mexico, Guatemala, Belize and northern Honduras. They spoke many languages, but were unified by a political and religious system in which lineage and rituals legitimised power. As such, the dead were important, and the living often kept the remains of many deceased relatives nearby, under the floors of the house or within the walls.

Esther Brielle at Harvard University and her colleagues studied remains at numerous burial sites in Belize from the Classic period to investigate how some of the buried people related to each other. They generated genomic data from hundreds of samples and used radiocarbon dating to work out when each person lived.

They found that 341 samples relate to 107 distinct individuals, and 24 of these individuals had skeletal elements found in two places: in the Plaza Tomb, beneath a house in the Maya site known as Muklebal Tzul, and in Bats’ub cave, 26.5 kilometres away on the other side of the Maya mountains.

In that cave were a total of 226 teeth from at least 24 people, arranged near the body of an adult female. Her head had been removed and in its place was part of a vessel containing a single jade bead. Fragments of a cranium, possibly her own, and mandibles with no teeth were found near the pelvis, alongside a large cache of teeth and an inverted bowl containing five cacao seeds. Nearby was an orange bowl decorated with a mythical hummingbird-serpent creature.

The genomic analysis showed she was the ancestor of some of the people interred in the elite tombs, and the collection of grave goods imply she was royal, write Brielle and her colleagues, who declined to speak to New Scientist.

It is possible that others in high society pretended she was their forebear to affirm their status, says Mirko De Tomassi at the Ludwig Maximilian University of Munich in Germany. “They connected themselves either biologically or ideologically to an ancestor to help them legitimise their power,” he says.

The genomic data indicates that only the top level of society in Muklebal Tzul brought teeth to the caves.

“Caves were sacred spaces because they were the entrance to the underworld – Xibalba,” says Angelina Locker at Vanderbilt University in Nashville, Tennessee. She posits that perhaps elite individuals were the only ones allowed to be in this “mouth” of the underworld, which would have been a place to communicate with the supernatural forces that the Maya people thought animated the world.

Members of high society may have taken teeth to the cave to venerate ancestors and make sure they made it to Xibalba, says Locker. Her research has shown how the Maya conceptualised the body as being divided into four components, one of which is called Ik’ and resides in the mouth, representing the breath of the soul.

Asta Rand at Nicolaus Copernicus University in Toruń, Poland, says teeth may have been chosen because they last a long time, but they were also significant in Maya culture and people would modify teeth by filing them or embedding jewels in them. “I suspect they’ve been collected from burials, but teeth can fall out or be pulled out during life, so there is also the possibility that some were removed during life,” she says.

Locker says teeth were symbolically related to grains of maize and to the idea of rebirth. “It could have been a way for the Maya to take the teeth and then plant them in the mouth of Xibalba so that person could be reincarnated later on,” she says.

Whatever their reasons for depositing the teeth, people would have had to make a multi-day journey across rugged terrain to reach the cave, says De Tomassi. He compares it to the Maya practice of pilgrimage to the sacred cenote at Chichén Itzá, in what is now Mexico, to deposit precious objects.