Did Volcanoes Kill Off the Hobbits? Evidence Mounts Over Why Our Tiny Relatives Homo Floresiensis Went Extinct

Tens of thousands of years ago, a tiny species of human existed on a small Indonesian island. Standing at around 1.1 meters in height, Homo floresiensis is thought to have lived on the island of Flores between 190,000 and 50,000 years ago.

Scientists discovered this strange species, often dubbed hobbits because of their small stature, in 2003, when their skeletal remains were found in a cave on Flores. Since then, their existence has been subjected to much scrutiny. Was it a distinct species or just a group of unusually small humans? How did it get to Flores? And why did it disappear?

Answering the latter, an international team of scientists now believes H. floresiensis may have been wiped out—at least in part—by volcanic eruptions.

An artist depicts Homo floresiensis. Scientists found a huge volcanic eruption that took place around 50,000 years ago coincided with the disappearance of H. floresiensis and three other large species found on the island of Flores. Reuters

Publishing their study in the Journal of Human Evolution, researchers looked at the composition of the fauna and other artifacts that were found on Flores from 190,000 years ago, including thousands of animal bones and stone tools.

This allowed them to build up a picture of what was happening on the island in terms of the types of animal and human species that lived there and how abundant they were. Researchers discovered that there was a "major shift" in the paleoecology and the subsequent behavior of the hobbits.

Most notably, they found a huge volcanic eruption that took place around 50,000 years ago coincided with the disappearance of H. floresiensis and three other large species found on Flores—giant storks, vultures and dwarf elephants. By 46,000 years ago, these creatures were no longer present on the island.

The cave where remains of Homo floresiensis was first discovered by a team of international scientists. Reuters

The team said successive volcanic eruptions probably had a "major influence" on how H. floresiensis responded to the climate of Flores and may well have played a role in the species' extinction. Potentially, the eruption disrupted the ecosystem, making it impossible for H. floresiensis to survive.

Researchers note that the dwarf elephants, which had a body mass of about 570 kilograms and were about the size of a small cow, likely formed an important part of the diet of H. floresiensis. If they disappeared as the result of the volcano, it could have caused a domino effect on the rest of the ecosystem.

Volcanic eruptions may have just been part of the story, however.

A Homo floresiensis skull is photographed next to the head of a modern man. H. floresiensis were often dubbed hobbits because of their small stature. Reuters

The team also shows how there is a shift in the type of stone tool being created around 50,000 years ago. Instead of using volcanic stone, there is a preference for chert—the stone of choice among modern humans.

It could be that humans arrived around the same time as the volcanic eruption and either killed off H. floresiensis directly, or they decimated the larger fauna on the island—including the dwarf elephants and giant storks—leaving the island natives with little chance of survival.

"Climate change, volcanism, and modern human arrival are all reasonable possible explanations (but not mutually exclusive) for this observed co-disappearance, but more research at Liang Bua and elsewhere on Flores is needed before any definitive statements are made about these events," the team wrote.