A brutal, centuries-long drought likely drove the extinction of Homo floresiensis, the ancient human species nicknamed “hobbits,” according to research published Thursday in the journal Communications Earth & Environment. The findings suggest the small-bodied hominins abandoned Liang Bua cave on the Indonesian island of Flores after rainfall plummeted and vital water sources dried up, impacting both the hobbits and the pygmy elephants they hunted.
The international research team, including scientists from the University of Wollongong (UOW) in Australia, analyzed chemical signals preserved in cave stalagmites and isotopic data from fossilized teeth of Stegodon florensis insularis, a now-extinct species of pygmy elephant. The data reveal a drying trend beginning around 76,000 years ago, intensifying into a severe drought between 61,000 and 55,000 years ago – a period coinciding with the disappearance of Homo floresiensis from the fossil record.
“The ecosystem around Liang Bua became dramatically drier around the time Homo floresiensis vanished,” said UOW Honorary Professor Dr. Mike Gagan, the lead author of the study. “Summer rainfall fell and river-beds became seasonally dry, placing stress on both hobbits and their prey.”
Homo floresiensis, first discovered in 2003 at Liang Bua, captivated the scientific community due to its diminutive stature – averaging around 3.5 feet tall – and primitive features. The species occupied Liang Bua cave for approximately 140,000 years, challenging conventional understandings of human evolution. While previous research indicated the species disappeared around 50,000 years ago, the cause of their extinction remained a mystery.
The stalagmite analysis provided a detailed reconstruction of past rainfall patterns. Simultaneously, oxygen isotope analysis of the pygmy elephant teeth revealed a growing reliance on dwindling river water as conditions became drier. The decline in the Stegodon population, a crucial food source for the hobbits, further exacerbated the situation.
“Surface freshwater, Stegodon and Homo floresiensis all decline at the same time, showing the compounding effects of ecological stress,” explained UOW Honorary Fellow Dr. Gert van den Berg. “Competition for dwindling water and food probably forced the hobbits to abandon Liang Bua.”
The research similarly acknowledges the potential for interaction with Homo sapiens, as modern humans were migrating through the Indonesian archipelago around the same time. Dr. Gagan suggested that climate change may have indirectly contributed to any encounters. “It’s possible that as the hobbits moved in search of water and prey, they encountered modern humans,” he said. “In that sense, climate change may have set the stage for their final disappearance.”
The UOW has been involved in research concerning Homo floresiensis since the initial discovery in 2003, with previous perform establishing the species’ similarity to Homo erectus. The current findings build upon decades of investigation into the unique evolutionary history of this ancient human population.
