A long stretch of life after the last possible child is, on the face of it, an evolutionary puzzle. Those decades cannot produce offspring directly, yet in humans they are routine. Women commonly live thirty or forty years past the point where childbearing ends, and this pattern is very unusual across the animal kingdom. Darren [...] The post Humans are one of very few species whose females live for decades after they can no longer have children. One explanation is the ‘grandmother hypothesis’: