Do We Really Need to Sleep 7 Hours a Night?  Recent research by Michael Gurven, director of the Broom Center’s Biodemography and Evolution Theme, compares sleep patterns between modern Americans and people in hunter-gatherer societies.   Gurven and his co-authors found that Americans on average sleep as much as people in three different hunter-gatherer societies where there is no electricity and where lifestyles have remained the same for thousands of years. The hunter-gatherer communities included in the new study, the Hadza and San tribes in Africa, and the Tsimané people in South America, tend to sleep even less than many Americans.  Recent media coverage includes National Geographic, The Economist, The Atlantic. National Public Radio. and the New York Times.