When the remains of tiny hominins — nicknamed hobbits — were found on the isolated Indonesian island of Flores in 2003, it sparked an epic hunt to understand the origins of these diminutive cousins of modern humans.

Now, discoveries of stone flakes used as primitive tools on the island suggest that the hobbit's ancestors were there a million years ago, at least 120,000 years earlier than previously thought (A. Brumm et al. Nature doi:10.1038/nature08844; 2010). "Whatever species made it to the island 1 million years ago, it was probably an ancestor of Homo floresiensis," says William Jungers, an anthropologist at Stony Brook University in New York.

The metre-high H. floresiensis lived on the island until at least 17,000 years ago, and its small stature probably evolved in response to the island's sparse resources. The simple stone tools demonstrate the skills of its ancestors — people who must have hopscotched across islands from mainland Asia, traversing deep and swift ocean channels, before arriving on Flores.

In 2005, Adam Brumm, an archaeologist at the University of Wollongong in Australia, found the first of about 45 stone tools while exploring a bowl-shaped gully on the island that was like "a hot, steamy wok". Three years later, researchers at Roskilde University in Denmark analysed the ratio of two isotopes of argon trapped in volcanic ash overlaying the tools to determine their age.

Previous tool discoveries showed that hominins had arrived on Flores by 880,000 years ago, suggesting that the hobbit's ancestors might have wiped out some of the island's peculiar indigenous animals, such as the pygmy elephant-like Stegodon sondaari and giant tortoises (Geochelone spp.), which both disappeared at around the same time.

The new finds imply that the hobbit's ancestors coexisted with the creatures for much longer, raising the possibility that a natural disaster was behind the disappearance of the animals.

The team will return to Flores this summer, hoping to find older sediments that could hold earlier evidence of the island's first hominins.