Sat Mar 7, 2015 12:17am GMT

Female killer whales live long and productive lives after they stop having babies, playing a critical role in survival of the pod as they lead the hunt for food, particularly in lean times, according to a study released on Friday.

Resembling in many ways their human counterparts, female killer whales breed between ages 14 and 40 but can survive well into their 90s, while male orcas, by contrast, die much younger, rarely making it past 50, according to the study in the journal Current Biology.

Killer whales join short-finned pilot whales and humans as the only species in which the females can live decades after menopause. In that time, the female killer whales, not burdened by childbearing, pass on important information to the other whales, says the study.

"The value gained from the wisdom of elders can help explain why female resident killer whales and humans continue to live long after they have stopped reproducing," the study said.

To study the orcas' behavior, marine mammal researchers from York and Exeter universities in Britain and the Center for Whale Research in Washington state analyzed 751 hours of video of killer whales taken over nine years on their annual Pacific Ocean salmon migrations off British Columbia and Washington state.

The older female whales "were more likely to lead group movement compared to reproductively aged females," the study said. Specifically, they are the leaders as the whales forage in groups for Chinook salmon, their primary food source.

And when things are tough, the older females step up even more, the study says.

"Leadership by post reproductive-aged females is especially prominent in difficult years when salmon abundance is low," the report says. "This finding is critical because salmon abundance drives both mortality and reproductive success."