For many years, anthropologists had been confident that the Aboriginal people of Australia had no contact with the outside world between their arrival on the continent roughly 40,000 years ago and the first landings by Europeans in the seventeenth century. But in 2013, publication of a DNA study drew that notion into serious question. Analysis of samples from Aboriginal people in the Northern Territory turned up markers suggesting an influx of migrants about 4,000 years ago. The archaeological record had already shown certain gains in tools and techniques at around that time, as well as the first appearance of the wild dogs that Australians call dingoes. Perhaps the newcomers were the cause?