Ancient drought drove extinction of 'hobbit' humans 61,000 years ago

Homo floresiensis vanished during a severe drought

A new study concludes that the extinction of Homo floresiensis, the small-bodied human species nicknamed the "hobbit," was driven by a severe, multi-thousand-year drought. The research, published in Communications Earth & Environment, shows the species left its primary cave home as freshwater and prey vanished.

The hobbits disappeared from Liang Bua cave on the Indonesian island of Flores around 50,000 years ago. The new climate evidence indicates they abandoned the site during an intense dry period that reshaped their entire ecosystem.

Stalagmites and teeth reveal a drying world

Researchers from the University of Wollongong and other institutions analyzed chemical records in cave stalagmites, which track past rainfall. They also studied oxygen isotopes in the fossilized teeth of Stegodon, a pygmy elephant the hobbits hunted.

The data reveals a long drying trend that began about 76,000 years ago. It intensified into a severe drought between 61,000 and 55,000 years ago, directly coinciding with the hobbits' disappearance from the cave record.

"The ecosystem around Liang Bua became dramatically drier around the time Homo floresiensis vanished," said lead author Dr. Mike Gagan. "Summer rainfall fell and river-beds became seasonally dry, placing stress on both hobbits and their prey."

A cascade of ecological collapse

The drought caused a chain reaction of scarcity. Stalagmite growth slowed, indicating less dripping water in the cave. The isotope data from Stegodon teeth showed the elephants were increasingly reliant on river water that was disappearing.

Around 61,000 years ago, the pygmy elephant population crashed. This collapse of a primary food source, combined with direct water scarcity, created an impossible situation for Homo floresiensis.

• Severe drought reduced surface freshwater.
• Key prey species, the Stegodon elephant, declined sharply.
• Homo floresiensis was forced to abandon Liang Bua cave.

"Surface freshwater, Stegodon and Homo floresiensis all decline at the same time, showing the compounding effects of ecological stress," said co-author Dr. Gert van den Berg. "Competition for dwindling water and food probably forced the hobbits to abandon Liang Bua."

Climate set the stage for a final encounter

The study clarifies that the primary driver of the hobbits' local extinction at Liang Bua was environmental. However, it also notes a consequential overlap in timing with the arrival of modern humans in the region.

Homo sapiens were moving through the Indonesian archipelago around the same period. The researchers suggest the drought may have pushed the vulnerable hobbit populations into contact with new competitors.

"It's possible that as the hobbits moved in search of water and prey, they encountered modern humans," Dr. Gagan said. "In that sense, climate change may have set the stage for their final disappearance."

The findings underscore how climate shifts can directly determine a species' fate. For Homo floresiensis, a species that survived in isolation for over 140,000 years, a prolonged drought was the catalyst that ended their story.