When the females of certain species can longer give birth, their importance to their families and social units doesn’t diminish. In fact, it grows. Michael Ellis has this Perspective.
What do short-finned pilot whales, belugas, narwhals, killer whales and human beings have in common? Well, they all have a complex social structure and in all five species the females regularly live long past the age at which they can give birth. In other words, they are all menopausal. What a strange concept. In all other mammals, males and females are reproductively active right up until death. There is, of course, a decline in reproduction as the animals age but there is no point at which they stop ovulating.
So why continue to live if you can't have babies? Well, the best guess is that in these species the oldest females are the ones with the vital information, the experience and the wisdom to make the correct decisions that enable the entire family unit to thrive.
In pilot whales, both males and females stay with their mother through her life. And their offspring stays as well. These long-lived marine animals are difficult to study but it is appears that movements and hunting techniques are coordinated by the oldest female in a pod.
Much more is known about the killer whales. Mothers and their offspring also stay together. Since female orcas can live over 90 years, these extended family groups can include multiple generations of related individuals. Activity, direction and rate of movement are set by the oldest female and she is the one who knows how to find salmon when the fishing is poor.