What do short-finned pilot whales, African elephants and human beings have in common? Well, they all have a complex social structure and in all three 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 animals 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 or stop producing sperm.
So why continue to live if you can’t have babies? Well the best guess is that in these three species the oldest females are the ones with the vital information, the knowledge and the experience 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 African elephant. Mothers and daughters with their offspring may stay together for 50 or more years. The most important unit in Africa elephant society are these extended family groups of related females and their young. Activity, direction and rate of movement are set by the matriarch.
During crises such as prolonged droughts she is the one who remembers where to go to dig the water hole. All members of the group look to her for leadership and to maintain order. She helps raise the young and can even lactate in emergencies without being pregnant.
In human beings as well it is Grandmothers that are the glue that holds the family together. In many so-called primitive tribes it is the older women who consistently gather the highest quality foods, they are the ones that can find and use important medicinal plants, they midwife the babies. We only have to look at impoverished inner-cities to see how important grandmothers are in raising young children.
Though they can no longer have babies these three older females benefit their tribes in critical ways and enable their own offspring to successfully raise young. Long live grandmothers, long live the crones!
This is Michael Ellis with a Perspective.