When Rainfall Faltered: How a Changing Climate Reshaped the Last Days of Homo floresiensis

The Valley That Held a Mystery

Liang Bua cave rises from the green highlands of Flores like the mouth of an old story. For decades, archaeologists walked past its entrance unaware that inside the limestone chamber rested the bones of a hominin unlike any seen before. When Homo floresiensis was identified in 2003, the scientific world scrambled to interpret a being that stood barely above a meter tall, carried a brain the size of a grapefruit, and nonetheless carved stone tools with practiced hands.

Flores was more than their home. It was their laboratory of survival, a place they adapted to for well over 100,000 years. Their abrupt disappearance around 50,000 years ago has remained one of paleoanthropology’s most enduring enigmas.

Homo floresiensis skull. Credit: Wikimedia Commons, CC BY-SA

A new study¹ now reframes the story not as a sudden vanishing but as the gradual unravelling of an ecosystem. Using a stalagmite from a nearby cave, researchers have pieced together the most detailed climate record yet for the region. Their reconstruction points to an unexpected culprit in the decline of the hobbits: a long, punishing drought that began nearly 61,000 years ago.

As one climate scientist put it:

“The stalagmite reads like a diary of water,” says Dr. Hana Mertens, a paleoclimate specialist at the University of Utrecht. “Each layer captures a shift in rainfall that would have affected every living thing on that island, hominins included.”

The renewed timeline now suggests that H. floresiensis and the pygmy elephants they depended upon were gradually pushed from the uplands as fresh water faded, creating conditions ripe for ecological displacement, migration, and possibly contact with Homo sapiens moving through Indonesia at roughly the same time.