Scientists think they may have just unlocked a major secret of womankind, and it came from a most unlikely source living out in the ocean known as the orca, or killer whale. Along with humans, the killer whale is just one of a few species on Earth known to get menopause, and a new study of the ocean-dwelling creature may have just answered the baffling mystery of why women get it at all, or at least gotten us closer to the answer.

Menopause, when a woman’s reproductive facilities suddenly shut down when they reach middle age, seems like a strange quirk of evolution, but a study published in the journal Current Biology indicates that there may be a very good reason for it, at least for the orca. Scientists found that female killer whales tended to get more generous with sharing food as they get older, but that becomes a problem if they continue having babies as their calves stick with them their whole lives, according to a University of Exeter statement.

As the female killer whale gets older, if it continues to give birth, it not only has more calves to feed, but it also continues to share more food with the group, and that becomes an unsustainable situation. Menopause is a natural stop sign that allows the killer whale to continue to become more generous without penalizing the calves, or vice versa. And that could be a vital discovery as we seek to understand our own evolution of menopause in the human species.

Professor Darren Croft explains in the statement that “older females are more closely related to the family group than younger females. This imbalance in local relatedness between mothers and their own female offspring means that older females do best to invest more heavily in the wider family group whereas younger females should invest more in competition.”

“Our previous work shows how old females help but not why they stop reproducing,” said Professor Darren Croft. “Females of many species act as leaders in late life but continue to reproduce, but this new research shows that old females go through the menopause because they lose out in reproductive competition with their own daughters.”