Maybe polar caps are melting from all the whale hot flushes
Scientists have discovered that Beluga whales and narwhals go through the menopause too
Beluga whales and narwhals go through the menopause – taking the total number of species known to experience this to five.
Along with humans, killer whales and short-finned pilot whales were the only others previously known to experience “the change” with most species being able to continue to reproduce until they die.
The study used data from the dead whales of 16 species and found dormant ovaries in older beluga and narwhal females.
The researchers believe they go through the menopause to prevent resources being taken away from their other children and grandchildren, but stay alive to help protect the younger pod members.Lead author Dr Sam Ellis, from the University of Exeter, said: “For menopause to make sense in evolutionary terms, a species needs both a reason to stop reproducing and a reason to live on afterwards.
“In killer whales, the reason to stop comes because both male and female offspring stay with their mothers for life, so as a female ages, her group contains more and more of her children and grandchildren.“This increasing relatedness means that, if she keeps having young, they compete with her own direct descendants for resources such as food.
“The reason to continue living is that older females are of great benefit to their offspring and grand-offspring. For example, their knowledge of where to find food helps groups survive.”
Research into human ancestors suggests they also lived among more and more relatives as they aged, and may have evolved in a similar way so they could impart their wisdom.
Senior author Professor Darren Croft, also of Exeter, added: “It’s hard to study human behaviour in the modern world because it's so far removed from the conditions our ancestors lived in.“Looking at other species like these toothed whales can help us establish how this unusual reproductive strategy has evolved.”
There has already been extensive research into the existence of the menopause among killer whales. Detailed observations of live beluga whales and narwhals have not yet been carried out.
The research was published in the journal Scientific Reports.
– © The Daily Telegraph