Menopause Is a 'Second Puberty' for the Brain

By the usual logic of evolution, menopause shouldn’t really exist. Even our closest relatives, chimpanzees, experience it only at the very end of life. Humans, along with a few long-lived whales, are the bizarre exception. We can live for decades after fertility ends. Evolutionary biologists have spent half a century trying to explain why. A species does not typically invest in a body that no longer reproduces. So why do we?