Matt Tocheri is the Canada Research Chair in Human Origins at Lakehead University and a Research Associate in the Smithsonian Institution’s Human Origins Program. He was awarded a Leakey Foundation Research Grant during our fall 2016 cycle for his project entitled “New archaeological excavations at Liang Bua (Flores, Indonesia).”
In 2003 and 2004, archaeologists excavating on the Indonesian island of Flores uncovered a partial human skeleton roughly six meters beneath the present-day surface of a cave called Liang Bua. Their discovery would soon spark intense scientific debates worldwide and attract a level of public interest rarely seen in any scientific discipline. The recovered skull revealed an extremely small, chimpanzee-sized brain (~400 cm3) while the limb bones showed this fully-grown adult would have stood about 1 m tall and had australopith-like body proportions. The remarkable discovery, which made the cover of the journal Nature in October 2004, presented the world with a new member of the human family tree called Homo floresiensis, referred to informally as the “hobbits” of human evolution.
The implications were startling: human biological diversity during the terminal Pleistocene was significantly larger than what it is today. Until relatively recently our species shared this planet with Neandertals and Denisovans as well as this even more distantly related evolutionary cousin that also walked upright, and made and used stone tools. What exactly happened to this branch of our human family tree is still poorly understood, but current evidence shows that they disappear from the Liang Bua stratigraphic sequence around 60–50 thousand years ago.
We cannot physically travel back in time in order to save this lineage of our family tree from extinction, but we can strive to learn as much as possible about when and why they ultimately went extinct, and whether members of our own species, Homo sapiens, played any direct or indirect role in the process. Building knowledge and understanding about Homo floresiensis provides an important and unique perspective on the ramifications of losing diversity—be it biological, cultural, or linguistic—and helps society and individuals make better, more informed arguments for preserving diversity among all species that survive today.
The stratigraphic sequence at Liang Bua does not end abruptly at 60–50 thousand years ago. A recently excavated 1 x 4 m test trench within the middle rear part of the cave led to the identification of deposits dated to between 46 and 24 thousand years ago that directly overly 60–50-thousand-year-old sediments. Our project, generously funded by The Leakey Foundation, will significantly extend these earlier excavations over a ~12 m2 area in this part of the cave. This offers an unprecedented opportunity to test whether Homo floresiensis and other associated endemic fauna (e.g., pygmy Stegodon) survived after ~50 thousand years ago. At the same time, our project has strong potential to reveal important new knowledge about the arrival, morphology, and behavior of the earliest modern human populations to reach Flores, as well as how this prehistoric dispersal may relate to the successful colonization of Island Southeast Asia and Australia ~50 thousand years ago by the ancestors of living Australomelanesian populations.