Giant turtle's demise the fault of humans, study says

Humans helped drive a species of giant turtle to extinction almost 3,000 years ago, according to a study in PNAS. It is one of the first cases that clearly shows that humans played a role in the demise of the giant, extinct animals known as "megafauna". An Australian research team discovered turtle leg bones - but not shells or skulls - on an island of Vanuatu.

The bones date to just 200 years after humans' arrival, suggesting they were hunted to extinction for their meat.

However, the turtles lived far longer than other megafauna - which included the famed woolly mammoth; while Australian megafauna is thought to have died out almost 50,000 years ago, it appears that these turtles survived for far longer - until the arrival of a people known as the Lapita.

Debate over what caused the megafauna to die out has raged for 150 years, since Darwin first spotted the remains of giant ground sloths in Chile. Possible causes have ranged from human influence to climate change in the past, even to a cataclysmic meteor strike.