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.
Nothing evolutionary like the menopause (or, to remain with female sexual oddities like tits, the female orgasm in humans and so on) is because “taking care of younger pod members” or anything like it. It’s always, but always, because the population is descended from those who carried the genes for those things, menopause, tits and so on. Those attributes led to more children surviving to have children, thus the genes spread.
It might well be that the post-menopausal whales do those things, that they’re beneficial to the survival of their genes down the generations, but it’s still not because nor in order to. It just happened than then the environment sorted through whether it led to that greater long term progeny production.