All the Buzz: Ancient Bee Nests Discovered in Fossilized Jawbones
About 20,000 years ago, long before humans explored the Caribbean, tiny bees were doing something very clever. Scientists have discovered that solitary bees—which live on their own instead of in colonies—used empty tooth holes in regurgitated animal bones as safe places to build their nests.
This unusual revelation was made by a doctoral student from the University of Florida and the Florida Museum of Natural History, Lazaro Viñola Lopez, along with a team from other institutions and universities. They detailed their findings in the Royal Society Open Science article “Trace fossils within mammal remains reveal novel bee nesting behaviour.”
Prehistoric Pellets
Now a postdoctoral researcher at the Field Museum in Chicago, Viñola Lopez and his colleagues had been studying fossils from a cave in the Dominican Republic, on the island of Hispaniola. The cave is a deep limestone sinkhole that served as a home for owls for thousands of years.
Owls swallow their prey whole, including rodents, birds, and even small sloths. Later, they cough up the parts they cannot digest, like bones, in tight bundles called owl pellets. Over time, layer upon layer of these pellets piled up on the cave floor and slowly turned into fossils.
Unexpected Architects
While cleaning fossilized jawbones from the cave, Viñola Lopez noticed something strange, according to the Field Museum news release “These fossils were the perfect home for ancient baby bees,” posted on the American Association for the Advancement of Science EurekAlert! website. The tiny holes where teeth used to be were filled with smooth sediment, which did not look like ordinary dirt that had fallen in by accident. It looked more like wasp cocoons.
Having become familiar with the ancient remains of wasp cocoons as an undergraduate, Viñola López wondered if insects had built these structures too.
To find out without damaging the fossils, the researchers used CT scans, a type of X-ray that creates detailed 3D images. The scans showed carefully made mud chambers in the holes, which were most likely nests for baby insects.
Busy Bees
The scientists believe mother bees mixed soil with their saliva to form the tiny nests. Each one was very small—smaller than the eraser on a pencil. Some nests even held grains of fossilized pollen, which would have been food for the bee larvae after they hatched.
The bees themselves were not found. Insects are fragile, and the warm, humid cave conditions made it hard for their bodies to be preserved. Even so, the nests were so unique that scientists named them as a new type of trace fossil, according to the Interesting Engineering article “20,000-year-old fossils reveal ancient bees found ‘perfect home’ in owl prey bones.” Trace fossils are signs of life, like footprints or nests, rather than the animals themselves.
The new fossil was named Osnidum almontei, in honor of Juan Almonte Milan, a Dominican paleontologist who first recognized the cave’s importance.
Unknown Inhabitants
Scientists are not sure whether the species of bees that built these nests are extinct or still in existence today. Some animals found in the cave have gone extinct, but many bee species in the Caribbean are still not well studied.
What is clear is that the bees chose their nesting spots wisely. The hard bone cavities protected their eggs from floods and from predators like wasps. This discovery shows how even tiny insects can be surprisingly creative—and how much we can still learn from the ancient past.
Discussion Questions
- Why do you think the bees chose empty tooth holes in bones as places to build their nests instead of other locations?
- Why do you think scientists can learn a lot from trace fossils, even when the animals themselves are not preserved?