Why Women Syncing Their Periods Is a Myth But Lionesses Ovulate Together

Lionesses rest in the bushes of the Masai-Mara Game reserve, Kenya, August 7, 2003. Lionesses sync their fertility cycles so that they can all raise their young together, research has revealed. Marco Longari/Getty

The theory that women's menstrual cycles align might have been discredited but lions do ovulate at the same time, research reveals.

While studying lions in Zambia, biologist Thandiwe Mweetwa noticed that lionesses within a pride will all have cubs around the same time, National Geographic reported.

When she looked into it further, Mweetwa learned lionesses sync their fertility cycles so that they can all raise their young together.

"Synchronized estrus is thought to increase reproductive success in the pride," Mweetwa said. "Having cubs at the same time means that mother lions can rely on each other to nurse, babysit, and protect the youngsters."

However, it remains a myth that human beings [women] can replicate a similar reproductive behavior.

A recurring claim is that people living in close proximity—such as several women sharing a dorm in college—synchronize their estrus cycles, which is evidenced by having periods around the same time. This idea, which caught on due to research by psychologist Martha McClintock in 1971, has since been debunked in several studies.