Why do we sleep? Why did sleep evolve? How much is enough? Do we die if we don’t get enough? Kate Rusk, Joe Alcock, Coffee Brown and special guest Gandhi Yetish discuss these topics in this episode of the EvolutionMedicine podcast. Gandhi has studied the Tsimane, a hunter horticulturalist group in Bolivia. This group, as well as hunter gatherers in Africa - the Hadza and the San - sleep about the same as us: just over 6 hours. What does that result mean for us iPhone gazing city dwellers?