Micromammals Tell a Mega-Story

Most research in archaeology happens in a lab. Despite the images of sweaty excavators and big hats that come to mind when “archaeology” is mentioned, the bulk of archaeology happens when the digging is done. It’s a truism among project directors that you plan three days in the lab for every one day in the field, but the essential work that goes on behind the scenes is largely invisible to the public.

I’m a zooarchaeologist – an archaeologist who studies animal remains – and I do most of my work in labs. Right now, I’m working at the Muséum national d’Histoire naturelle in Paris, where I study the bones of micromammals like mice and voles. These tiny remains were excavated from Bronze and Iron Age sites on the island of Sardinia (c. 1700-300 BCE), and despite their small size, they help me answer big questions about the cultures I study. Micromammals are sensitive to the environments around them. Different species have particular preferences for habitats and living conditions, which means that identifying the micromammals at a site is a way to reconstruct the site’s environment. And reconstructing the ancient environment is fundamental to understanding everything from past economies to climate change.

I use a microscope to examine bones for evidence of digestion by predators

A typical day of zooarchaeology includes multiple projects. Today, I’m working on three. I begin the day by tackling a taphonomic analysis of the micromammal remains. Taphonomy is the study of how ancient bones are incorporated into archaeological sites, and it includes everything that happens to the bones after the animals die. You can imagine why taphonomy would be important for interpreting ancient bones. Let’s say, for example, that the ancient environment was swampy, so the local micromammals were adapted to wet terrain. But if there were grasslands nearby, an ancient owl could nest in the swamp but hunt in the grasslands, scattering bones of grassland species around its nest. A case like this will give you a confusing mixture of grassland and wetland species showing up together – so what was the ancient environment really like? A careful taphonomic analysis can sort out which species died at the site and which were brought there by predators, helping differentiate the immediate local conditions from the wider surroundings.

Special software lets me capture detailed images of the micromammal teeth

After a morning in front of the microscope recording taphonomic clues, I’m ready to move to my second project. This project uses geometric morphometrics – a kind of spatial statistics – to analyze the shape of micromammal teeth. The shape of the teeth shows genetic plasticity, meaning that it changes depending on which groups of micromammals bred with each other. Looking at the shape of ancient teeth is therefore a way of tracing population dynamics, and when the only way new micromammals get to an island is by sneaking onto ships, ancient micromammal interactions become a proxy for ancient human interactions.

Drawers full of tiny reference skeletons at the Muséum national d’Histoire naturelle

I spend several hours taking images of the micromammal teeth. When I’ve captured images of all of the teeth, I’ll use specially developed software to compare the teeth with each other and with teeth from archaeological sites around the Mediterranean. Capturing the images takes up the major part of my day, but it’s only the beginning. Outlining each tooth so I can compare their shapes will take days. It’s a slow process, and I’ll work on it a little at a time after I return to the states.



I have just about an hour left in my day, so I decide to spend it studying. My third, long-term project is to do an environmental reconstruction for my site in Sardinia – Sa Conca Sa Cresia – which I excavated with my colleague Mauro Perra in 2009-2011. Even though we completed the excavations a while ago, I’ve only recently finished sorting the heavy fraction to remove the tiny micromammal bones. To prepare to do a complete environmental study, I first consult The Atlas of European Mammals to see which species are currently known to exist on the island. Then I visit the Muséum’s reference collections to familiarize myself with the characteristics of these species’ bones – and especially their highly diagnostic teeth.

The number and shape of the cusps make teeth “diagnostic,” meaning they can usually be assigned to a species

By the end of the day, my brain is fried. I cover the microscopes, turn off the lights, and make my way to the metro line 7, then transfer to the 6. I’m in a bit of a daze, but it’s a good kind of exhaustion – similar to how muscles feel after a trip to the gym. It’s an exhaustion that lets me know I deserve to take the night off. And there’s no better place for a night off than Paris.