Moreover, at about that time, new techniques for altering dangerous plants to make them edible also appeared in Australia. For instance, while plants known as cycads can be toxic, soaking or fermenting their kernels can remove the poisons.
"Aboriginal Australians use the fruits of these plants as an important food source despite them being highly toxic," Pugach said.
The researchers caution the migration "may not have actually been from India, but from some population somewhere else that subsequently no longer exists, but whose closest living relative - at least, among populations we examined - are Dravidian-speakers from southern India," Pugach said.
The researchers also emphasized they are not claiming some Indian group members are the ancestors of aboriginal Australians. "The migration happened about 4,000 years ago. By that time, people lived in Australia for more than 40,000 years," Pugach said.
It remains uncertain why this migration might have taken place more than 4,000 years ago. Environmental changes might be one cause, "although I don't know of any significant environmental changes then," Pugach said. Then again, it could "simply be wanderlust. Humans have always liked to migrate, and don't seem to need a reason to want to do so."