Mother-daughter conflicts have proven to be an inexhaustible resource for writers, artists, and filmmakers, and it turns out they also play a large role in the reproductive lives of killer whales.

Mother-daughter conflicts have proven to be an inexhaustible resource for writers, artists, and filmmakers, and it turns out they also play a large role in the reproductive lives of killer whales.
According to a study recently published in ‘Current Biology,’ older female killer whales experience menopause as a means of avoiding competition between themselves and their female offspring. 
Researchers determined that calves born to the more senior killer whales have a lower chance of survival compared to those birthed by the more junior members of the community.
After extensive study, the team determined the explanation for that outcome as, “selection will favor younger females that invest more in competition.” 
However, when the older killer whales filled the role of mother’s helper rather than mother, the pod experience greater success overall.
The team asserts that due to the advantages inherent in having the younger generation reproduce and the older assist, the occurrence of menopause evolved.
A press release about the study also notes, “the reason older females stop reproducing has more to do with conflict between mothers and their daughters than it does with cooperation.” 
Notably, killer whales are among only 3 species known to experience menopause and live long after their reproductive years have passed. 
According to the release, "Female killer whales typically start reproducing by age 15. They stop reproducing in their 30s or 40s, but they can live to be more than 90."