What the Maya did with human bones in their cave rituals was gruesome

Archaeologists working in a Guatemalan cave report hundreds of Maya bones, mostly in fragments. Many show clear signs of injury, arrangement, and ritual handling.

The site sits beneath the ancient city of Dos Pilas, and the pattern they are seeing is not of full skeletons but of carefully selected parts.

“The emerging pattern that we’re seeing is that there are body parts and not bodies. In Maya ritual, body parts are just as valuable as the whole body,” said Michele Bleuze, a bioarchaeologist at California State University, Los Angeles.

A bioarchaeologist studies human remains from archaeological sites to understand health, trauma, and cultural practices in the past.

Inside the Maya blood cave

At the Society for American Archaeology meeting on April 24, 2025, researchers outlined the evidence from Cueva de Sangre.

This included stacked skull caps, cut marks made with beveled tools, and pigments and blades used in ceremonies.

They also reported a deposit with more than 100 adult and juvenile bone fragments. Many were identifiable, and several showed trauma consistent with events at or near death.

Michele Bleuze is part of the team leading this work in the Petexbatun region of northern Guatemala. The cave is flooded much of the year, so people likely entered during the dry months when passageways became accessible.

Reading injuries in bones

“There are a few lines of evidence that we used to determine that this was more likely a ritual site than not,” said Ellen Fricano, a forensic anthropologist at Western University of Health Sciences. Her specialty is examining injuries to bones to determine what happened around the time of death. 

The team points to marks on a forehead fragment that match a tool with a beveled edge and a similar sharp cut on a child’s hip bone.

The injuries are perimortem, which means they happened at or around the time of death, after which bone becomes dry and breaks differently.

Why caves mattered to the Maya

At Dos Pilas, a regional cave survey showed that major buildings were deliberately aligned with caves and that these underground places were central to the city’s sacred geography.

This fit a wider pattern across the lowlands where caves served as ritual spaces tied to political power and community life.

Another famous example is Actun Tunichil Muknal in Belize. This cave, with human remains and ceremonial artifacts, is protected by authorities today due to its sensitivity and scientific value.

These sites were never ordinary living spaces. The materials left on the surface often record ceremonies held in darkness and in water.

Timing the rituals with the seasons

The Cueva de Sangre passage floods for much of the year, so access likely came between March and May when water levels drop.

That timing matters because communities often prayed for rain just before the wet season, and associated these rites with the rain god Chaac.

A Late Classic study links increases in cave ritual activity with periods of drying climate. It argues that ceremonies for rain intensified when drought threatened crops and stability.

This helps explain why a flooded cave that becomes reachable at the end of the dry season would host offerings aimed at bringing storms and a good harvest.

Confirming the context

Earlier cave work in the same region used chemical deflocculants to break down sticky cave mud and release hidden artifacts and bones. This method revealed that waterlogged zones can mask the scale of ritual deposits.

When tested at Cueva de Sangre, the technique showed that surface collecting alone undercounts material and can miss earlier use that is sealed beneath thin layers of silt.

These insights also showed that obsidian blades and other small items related to bloodletting rituals are far more common than quick surveys suggest.

The shiny, volcanic glass often turns up with iron-rich pigment, known as red ocher in cave contexts. This association matches the blood, pigment, and prayer cycle seen in Maya ritual.

Stacked skull caps

The four stacked skull caps are not a random scatter. Their arrangement signals a planned act that treated specific bones as meaningful offerings and not simply as remains left after a funeral.

“Right now, our focus is ‘who are these people deposited here’ because they’re treated completely differently than the majority of the population,” said Bleuze.

When bones are intentionally positioned and left on the surface, archaeologists are looking at a ritual deposit rather than a burial. 

Why this Maya cave matters

Dos Pilas and its surrounding caves have long offered a window into how cities mapped sacred spaces onto their plans.

Cave work at the site has shown that artifacts from caves can represent a large share of a city’s material culture. This means that rituals consumed real resources and labor on a regular basis.

That scale matters for history. If people invested time, food, tools, and lives into ceremonies for rain and renewal, then shifts in climate or politics would ripple through both ritual life and civic order.

A careful path forward

The team plans ancient DNA and stable isotope studies to learn who was brought into the cave and whether they came from nearby communities or farther away.

Isotopes reveal diet and water source histories locked in bone and tooth minerals, which can indicate origin and movement.

Further analysis also looks for patterns across the cave’s different chambers. Cueva de Sangre is a complex system with multiple entrances and levels.

Careful mapping helps distinguish separate deposits that may reflect different groups, dates, or purposes within the same sacred landscape.

We do not yet know whether the people represented in the cave were locals, captives, or dedicated ritual specialists. We also do not know how often the cave hosted ceremonies during the centuries it was active.

New tests will narrow these questions. As the evidence grows, so does a clearer picture of how the ancient Maya used caves to seek rain, express devotion, and manage crisis in a region where water could make or break a season.

Information presented (contribution 104) at the meeting of the Society for American Archaeology on April 24, 2025.

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