Island find stirs Hobbit debate

By Helen Briggs
Science reporter, BBC News

The bones were found in caves

The discovery on South Pacific islands of ancient bones thought to belong to a tribe of tiny humans has raised new anthropological questions.

Radiocarbon dating suggests the little people lived on the islands of Palau a few thousand years ago.

Scientists believe they were true humans who shrank, perhaps because of a genetic disorder or lack of food.

The find fuels new debate over the "Hobbit", a tiny human that lived on the island of Flores, 2,000km away.

Some experts believe the Hobbit was a distinct species of human, Homo floresiensis, rather than Homo sapiens like us.

Modern humans certainly can be subject to the island dwarfing mechanism Prof Chris Stringer

But others think the Hobbit's strange features, such as its particularly small brain, cannot be reconciled with our present knowledge of the origins of modern humans.

They believe the remains are of true humans who were diseased in some way.

Chance find

The latest twist in the Hobbit story concerns the discovery of the bones and skulls of 26 individuals in caves on small islands in the Pacific nation of Palau. The fossils have been radiocarbon dated to between 1,400 and 3,000 years ago.

One male individual weighed around 43kg (94lb) while a female weighed 29kg (64lb). They would have grown to about 4ft (120cm) tall.

However, while small, their skulls had many human-like features.

Professor Lee Berger from the University of the Witwaterstrand, South Africa, made the discovery while kayaking around the islands on holiday. He thinks the people were true dwarfs rather than a separate human species.

They simply grew smaller, perhaps because of the pressures of island life or a genetic disorder, he says.

Writing in the journal PLoS One, Professor Berger and colleagues argue that the features seen in the Hobbit fossil in Flores may also be an adaptation to island life, "regardless of taxonomic affinity".

He said: "Under any circumstances the Palauan sample supports at least the possibility that the Flores hominins [modern humans, their ancestors and relatives since divergence from apes] are simply an island adapted population of H. sapiens, perhaps with some individuals expressing congenital abnormalities."

Chris Stringer, lead researcher in the human origins programme at London's Natural History Museum, who was not part of the study, thinks it is a plausible explanation.

The phenomenon, known as island dwarfing, has been seen in many animals, including extinct mammoths and elephants.

"It shows the plasticity of the human skeleton - modern humans certainly can be subject to the island dwarfing mechanism," Professor Stringer told BBC News.

He believes the new find has limited relevance to the Flores story, because the Hobbit was a "distinct and primitive species, not a human pathology".

Others, though, take an opposing view.

He added: "Some people just cannot accept that it [the Hobbit] is what it claims to be. It's a very challenging find."