A severe drought caused by climate change may have led to the extinction of the diminutive human species known as Homo floresiensis, or the Flores Man, around 50,000 years ago. The hobbit-like species, which inhabited the Indonesian island of Flores, is thought to have vanished along with their primary food source, the pygmy elephants known as stegodons, due to a drastic reduction in rainfall.
Researchers analyzed stones near the original Homo floresiensis site of Liang Bua to reconstruct paleoclimatic changes over time. According to Yle, they measured concentrations of different isotopes of magnesium, calcium, and oxygen in these stones. The analysis revealed that the average annual rainfall in the region decreased by 38% between 55,000 and 76,000 years ago, aligning with the period when both Homo floresiensis and the stegodons began to decline.
Professor Michael Gagan from the University of Wollongong in Australia commented on the findings. "There is no evidence for catastrophic volcanic eruptions occurring at that time," he said. For a long time, it was believed that volcanic activity exterminated the species, but Gagan and his colleagues focused on the idea that climate change brought about the end of Homo floresiensis.
By 50,000 years ago, summer rainfall had fallen to an all-time low of just 430 millimeters per year. The decline deprived both the Flores Man and the stegodons of the water necessary for survival. As the climate continued to dry, resources likely decreased to the point that the stegodons, which needed large amounts of water like modern elephants, left their homelands in search of water.
Researcher Michela Leonardi from the University of Cambridge noted the impact of the changing climate. "We know that life can be very difficult if there is no water," she said, as reported by Euronews. She stated that the findings make sense because the availability of water is the main driving force of change for both humans and animals. Leonardi added that while both species showed an extraordinary ability to adapt to the constraints of island life by becoming dwarf forms, the rapid climate change event would have occurred much faster than life-saving mutations could have developed.
Stegodons, small relatives of elephants, were an important food source for the Flores Man, and they are believed to have coexisted for around a million years.
Homo floresiensis, nicknamed hobbit due to their small stature, grew to only about 1.1 meters tall and weighed between 16 to 28 kilograms. Their cranial volume was only 400 cubic centimeters, less than that of modern humans. Despite that, stone tools and weapons used by the Flores Man were found, indicating a level of sophistication.
The place of the Flores Man in the human family tree is still unclear. Previously, researchers thought that Homo floresiensis died out when they came into competition with Homo sapiens. Professor Gagan considers it possible that the Flores Man encountered the migrating modern human, Homo sapiens. However, more recent research suggests that Homo floresiensis probably disappeared before modern humans arrived on Flores.
According to IFLScience, Homo sapiens arrived on Flores around 46,000 years ago. This evidence suggests that Homo sapiens were not responsible for the extinction of Homo floresiensis. "Given that Homo sapiens went to Australia by around 60,000 years ago, it's impossible to rule out a scenario in which Homo sapiens interacted with Homo floresiensis on the island of Flores," the researchers stated. Even if Homo sapiens had nothing to do with their disappearance from Liang Bua, interaction is still possible.
The researchers presented two possible scenarios for the ancient inhabitants of Flores. The first involves the stegodons staying put and dying out en masse due to a lack of water. In this scenario, increased vulnerability to hunting by Homo floresiensis may have occurred as they gathered around their ever-shrinking drinking spots. Alternatively, the stegodons may have migrated away from Liang Bua in search of more abundant rainfall near the coast. In this case, Homo floresiensis may have followed their prey into these new lands, coming into contact with an array of new hazards.
The decline in precipitation led to a reliance on summer monsoons to refill key watering points, which were crucial for survival. The reliance left the stegodons with scant access to water during the annual dry season, and similarly affected the Flores Man.
The article was written with the assistance of a news analysis system.