Measuring just 1 meter (3.3 feet) tall with brains the size of modern chimpanzees, Homo floresiensis once called the remote Indonesian island of Flores home. More popularly known as the “hobbit” people, new research published in the Journal of Human Evolution suggests these ancient humans died out some 50,000 years ago because of a disastrous trifecta of dramatic events.
First described in 2004, H. floresiensis remains were found during a 1965 archaeological excavation conducted in a limestone cave called Liang Bua on the island of Flores. The island itself is prone to dwarfism not just in humans, but also in animals like the pygmy elephant. Archaeologists had believed the pygmy people had lived alongside modern humans for tens of thousands of years, before dying out as recently as 13,000 years ago. But in 2016, research found they actually died off right around the time Homo sapiens arrived on the island.
It was also around this time that all large animals on the island died out, including pygmy elephants the size of a modern cow, two species of large carnivorous birds – the 1.8-meters-long giant marabou storks and a vulture – and Komodo dragons.
“It is of great interested why all five of these relatively large-bodied taxa disappear together,” wrote the authors. But they think we now know why: “Climate change, volcanism, and modern human arrival are all reasonable possible explanations (but not mutually exclusive) for this observed co-disappearance.”
They dated more than 284,000 animal remains and 10,000 stone tool pieces found in sediment dating as far back as 190,000 years. Sediment samples show a volcanic eruption around 50,000 years ago that caused a pyroclastic flow – a cloud of hot gas and rocks that decimates the landscape, and is probably responsible for the deaths at Pompeii. Researchers say the eruption could have killed off H. floresiensis, but ecosystems typically recover within decades of volcanic eruptions, so it is unlikely.
Other dated material from the cave shows how the entire ecosystem changed around this time. All four of the previously mentioned large fauna lived alongside H. floresiensis, but these species last show up in the area of Liang Bua about 50,000 years ago. So, if not a volcanic eruption, what caused this mass extinction? Modern humans, probably.
An “abrupt and statistically significant shift in raw material preferences due to an increased use of chert” occurred around 46,000 years ago, indicating Homo sapiens arrived on Flores around 46,000 years ago. It’s the earliest evidence of modern humans in Indonesia and also could be the catalyst in this ecosystem-wide shift.
H. floresiensis commonly made their tools from a volcanic rock called silicified tuff. Meanwhile, modern humans were more fond of chert, and the presence of these tools suggests either H. floresiensis left the island and came back later with new tools, or modern humans showed up with them. If the latter, modern humans would have been much more capable of hunting elephants to extinction, an event that would have caused a trophic cascade, killing off the two large scavenging birds and forcing Komodo dragons to relocate. Because of this, the “hobbit” people probably wouldn’t have had a large enough food source and would have starved to death.