巨型恐鸟。图片由 Joseph Smit 提供，属于公共领域，通过 Wikimedia Commons 提供。 The giant moa, an extinct group of flightless birds native to New Zealand, once reigned as one of the tallest and most impressive avian species ...

Modern life makes us tired, right? But research from societies in Africa and South America suggests people in the ancient world slept only 6.5 hours a night.