From the mouths of ancient Pacific pioneers come tantalising tales of the past

Some insight into calcified plaque (dental calculus) research in the Pacific, a personal perspective.

Go to the profile of Monica Tromp
Jan 20, 2020

In 2009 I presented research for the first time at an academic conference; the annual conference of the Society for Hawaiian Archaeology in Honolulu, Hawai'i. I presented preliminary results from my very first dental calculus research project focused on the diet of early Rapanui that I had been working on with John Dudgeon at Idaho State University in the USA. I was an undergrad and extremely new to archaeology, but found a very welcoming audience at this conference. One of those people, a well known Pacific archaeologist David Addison, was extremely excited about what we might be able to find out about some of the first colonists of the Pacific from their dental calculus. He suggested I go do a PhD with Lisa Matisoo-Smith and Hallie Buckley at the University of Otago in New Zealand, where bioarchaeological research had just begun on the oldest cemetery site in the Pacific, Teouma. A few years and degrees later, that is exactly what I did.

Lapita distribution map
A map showing the distribution of the Lapita culture and associated sites. The dotted line indicates the boundary between Near and Remote Oceania mentioned in the text.

Teouma is a very important archaeological site in the Pacific because it is the oldest and only known cemetery site of the first colonists of Remote Oceania. Austronesian speaking people entered the Western Pacific around 3300 years ago. This movement marked a significant period of encounter, interaction and communication with the established Papuan speaking populations of Near Oceania, leading to the emergence of the distinctive cultural complex that Paific archaeologists refer to as ‘Lapita’. 

Plant microparticles from dental calculus.
These are examples of microparticles that can be found in dental calculus: plant (green), diatom (blue) and fungal microparticles that have been extracted from dental calculus in the Pacific.

It's very unusual to find such well preserved burials in the Pacific, especially 3000 year old ones, because bone generally doesn't preserve in hot and humid climates. The same is true for things made of plant materials and also food. One of the big advantages of studying calcified plaque or dental calculus is that you can find out a lot about these otherwise invisible parts of people’s lives. Plaque calcifies very quickly and can trap just about anything you put inside of your mouth - much like the infamous Jurassic Park mosquito in amber - but they are incredibly small things that you can only see with a microscope. In this case those things were mostly from plants that people ate and made things out of, but in another recent project, we found lapis lazuli in the dental calculus of a Medieval nun, which told us that she had been a skilled artist during her lifetime. The wide, and often unexpected, range of things you can find in calcified plaque makes what I do both incredibly exciting and frustrating at the same time.

Monica looking at samples in the scanning electron microscope (SEM) located in the Max Planck Science of Human History, Department of Archaeology's microscopy facility in Jena, Germany.

One of the more frustrating things about looking at microparticles (besides the hundreds to thousands of hours staring into a microscope) is that once you start being able to recognise when a microparticle is meaningful and not just a speck of dirt, there's rarely a database to compare them to - this is true of all microparticle work, but even more so in the Pacific and other areas of the world that have not been a huge focus for this kind of research until recently. Part of the work that resulted in this paper included making a microparticle reference database from tiny bits of pieces of leaves, twigs, bark and seeds from the expertly curated herbarium located in the Forestry Department in Port Vila, Vanuatu. 

Barringtonia edulis
A herberium specimin of Barringtonia edulis or cutnut, which is still an important food in Vanuatu today.

While visiting the Vanuatu National Herbarium, I was also shown around the nearby forests by Frazer Alo who really helped solidify just how "unnatural" most seemingly natural forests are when you know what you're looking at. All of these forests are full of fruit and nut producing trees, yams, taro, edible leaves and fiberous bark and leaves for creating fabric and string.

Forest near Port Vila
Forest near Port Vila comprised of several food producing trees and root crops mixed in with grasses.

Within archaeology and the general pubic, there's often more interest in how large scale farming came about and how people domesticated certain plants and animals. However, I think it's equally, if not more interesting to think about how people adapted to what was already available to them. It's often assumed, in Remote Oceania, that without domesticated crops and animals people would not have done as well as they did. This is actually quite difficult to prove or disprove with the current evidence in the region today. There've been extremely few studies of what the environment was like just before, during and just after human settlement of Remote Oceania and so currently it is not possible to know for sure which plants were already there and which were brought with colonists. Hopefully, over time and with funding, this research will be done at some point. For now, we have a hint from the microparticles uncovered from the Teouma people's dental calculus. 

Based on the results presented in our paper, leaves and bark from trees and shrubs were clearly quite important to these early colonists. All of these plant parts could be important for food, medicine, fibre and/or ritual, depending on the plant. Unfortunately, for the most part I was unable to tell exactly which plants the microparticles were from. We cannot yet say whether they were brought from the west or if they were already there when people arrived, though it is likely a combination of both. 

On the left are a few bunches of bananas waiting to be used at a wedding feast in Uripiv, Vanuatu (photo courtesy of Rebecca Kinaston), on the right is an example of the volcano-like shape of banana leaf phytoliths.

One plant that was very clear was banana - both seeds and leaves. Domesticated bananas, like those we find in the supermarket today, have very small or no seeds - this is also true in the past for most domesticated bananas. The fact that there were banana seed phytoliths found at Teouma, far from where they were domesticated in Papua, likely means that people brought these bananas with them from Papua when they emigrated to Vanuatu. However, there is also a small chance that they were already there when people arrived. Banana leaves are a less surprising a find, because they are used for everything from cooking to fabric making throughout the Pacific.

Recently, new scientific techniques such as genetic and proteomic analysis are being used to look even deeper into dental calculus. For example, a 2018 study of Mongolian steppe herder dental calculus has shown that, despite being unable to digest lactose, people have been eating or drinking sheep, goat and cattle dairy products since 1300 BC; the oldest evidence of dairying on the East Asian Steppe to date! We’ve also just scratched the surface in terms of what we might be able to learn about ancient oral microbiomes and a bunch of other health and disease indicators from the past. I can't wait to see what else we will find out from the mouths of these and other ancient Pacific pioneers.

This behind the paper post is referring to a paper can be found here: Exploitation and utilization of tropical rainforests indicated in dental calculus of ancient Oceanic Lapita culture colonists

Go to the profile of Monica Tromp

Monica Tromp

Senior Laboratory Analyst, Southern Pacific Archaeological Research (SPAR)


Go to the profile of Tristan Russell
Tristan Russell about 1 month ago

Very interesting research