Behind this mask lies the well-preserved face of someone who died many thousands of years ago, in the coastal desert of what is now northern Chile and southern Peru. A new theory may explain why the locals there began mummifying their dead.
A number of human cultures developed a tradition of mummification. The Chinchorro people of South America were the first. Their mummies are between 7000 and 8000 years old, predating the earliest evidence of mummification in Egypt by about 4000 years.
Now Pablo Marquet of the Santa Fe Institute in New Mexico and colleagues may have worked out why the ancient hunter-gatherers began to handle their dead this way. It may all be down to the environment.