Ancestors 'had less sleep' than we do

Our ancestors may have got less sleep than we do, a study suggests.

US researchers studied the sleeping patterns of traditional societies in Africa and South America, whose lifestyles closely resemble ancient hunter gatherers.

They monitored 98 people for 1,165 nights, and found that they slept for an average of 6.5 hours per night.

By comparison, the scientists said that most people in the US get about seven hours, according to a large sleep poll.

The new study, published in the journal Current Biology, also finds that temperature played a greater role than light in shaping sleeping patterns.

Prof Jerome Siegel, from the University of California, Los Angeles, said: "The issue is: what is the data on how sleep has changed?

"And it occurred to me that these groups, which are rapidly disappearing, give the last opportunity to really know what human sleep was like before we all created our various civilisations.

"What is absolutely clear is that they don't sleep more than we do."