Why menopause keeps evolving in whales -Comparing data on toothed whale species that do, and do not, experience menopause suggests that prolonged female postreproductive life allows whales to improve their offsprings’ and grand-offsprings’ survival chances. Older female whales such as killer whales (Orcinus orca) share food and become “repositories of long-term ecological knowledge”, explains animal-behaviour researcher and study co-author Sam Ellis. Menopause also seems to reduce reproductive competition between mothers and daughters. The hormone changes killer whales go through are similar to those in menopausal humans, but “as to hot and cold flushes, we've got no way of telling yet”, Ellis says.