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Ancient bees found nesting inside fossil bones in rare cave discovery

Ancient bees pulled off a bizarre survival trick—turning fossilized bones in a cave into their own ready-made homes.

Date:

April 3, 2026

Source:

Florida Museum of Natural History

Summary:

Thousands of years ago in a cave on Hispaniola, an unusual chain of events left behind a rare scientific treasure: bees nesting inside fossilized bones. After giant barn owls repeatedly brought prey like hutias into the cave, their remains accumulated in silt-rich chambers—creating a strange underground environment. Later, burrowing bees took advantage of the soft sediment and even reused tiny cavities in fossilized jaws and bones as ready-made nests, coating them with a smooth, waterproof lining.

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Paleontologists working in a cave on the Caribbean island of Hispaniola have discovered the first known instance of ancient bees nesting inside preexisting fossil cavities. Credit: Viñola-López et al. (2025) CC BY

A giant barn owl, a type of rodent called a hutia, and a burrowing bee entered a cave. Only two of them left. Which one stayed behind? The answer is the one that cannot fly.

This unusual chain of events likely unfolded thousands of years ago on the Caribbean island of Hispaniola. The owl carried the hutia back to its cave to feed its young. The meal ended quickly, and the remains of the unlucky rodent were left scattered across the cave floor. Much later, a bee arrived, searching for a place to build its nest among the debris left behind.

How Bees Turned Fossil Remains Into Nests

The bee began digging into the fine clay-rich silt that had built up in the darker parts of the cave. Before reaching the depth it needed, it encountered the remains of the hutia.

This turned out to be useful. The hutia's teeth had once been held in small sockets in the jaw, known as alveoli. Although the teeth themselves were gone, these hollow spaces remained intact and empty. Their size closely matched what the bee needed for a nest.

Over time, more bees followed, using these natural cavities inside fossilized bones as ready-made nesting sites. Long after the owl, hutia, and possibly even the bees had disappeared, paleontologists uncovered this unusual record preserved in stone.

A Careful Observation Leads to a Discovery

The discovery might have been missed if not for careful attention during excavation.

"Usually, when collecting fossils, you get all the sediment out of the alveoli while cleaning the specimen," said Lazaro Viñola Lopez, who excavated the fossils while working as a doctoral student at the Florida Museum of Natural History.

Viñola Lopez was particularly interested in this species of hutia, which was rarely found elsewhere on the island. In the Cueva de Mono in the southern Dominican Republic, he uncovered thousands of fossils from what appeared to be the same species. The cave had likely served as a long-term feeding site for giant barn owls, which repeatedly brought prey back to the same location over many generations.

Rather than immediately cleaning the fossils, he inspected them closely. One cavity stood out because its inner surface was smooth instead of rough like bone.

Mistaken Identity: Wasps or Bees?

"I'd seen something similar in Montana when I was collecting dinosaur fossils in 2014," he said. At the time, he and his colleagues found wasp cocoons mixed in with fossil material. He initially assumed the same explanation applied here. He recalls thinking, "it would be nice to write a short paper reporting the occurrence of these wasp nests in the mandibles."

He shared the idea with his colleague Mitchell Riegler, another doctoral student at the museum. Riegler was not immediately convinced. "I was like, Lazaro, that's a niche project, and I have a lot of other things to do."

The idea sat on hold until Riegler took on a challenge from a former advisor to write a scientific paper within a week.

"He and I played this game back and forth in which we tried to write a paper in a week."

At first, the team believed they were documenting wasp nests. But after reviewing research on ichnofossils, which are traces of past activity such as footprints, droppings, or nests, they realized something did not match.

Wasp nests typically have rough walls made from chewed plant material and saliva. The structures in the fossils were smooth. Bees, however, often coat their nests with a waxy secretion that creates a waterproof, polished interior. This detail revealed the true identity of the nest builders.

They had been studying bees, not wasps.

A Rare and Unprecedented Behavior

This correction made the discovery far more significant. There is only one other known case of burrowing bees nesting inside a cave, and none where bees used pre-existing fossil structures without altering them. A previous report described bees dri