Grandma Orcas Are The Wisest Of Them All, And We're Not Surprised
Female orcas of an advanced age - including the wild whale named Granny, who's believed to be something like 103 years old - aren't a burden on their families. These old whales, in fact, are the opposite: Postmenopausal orcas lead their pods to fish, particularly when times are rough.
The presence of a female past child-bearing years - just like in humans - is linked to increased survival for her offspring, as Lauren Brent, an animal behavior expert at the University of Exeter in the U.K., told The Dodo. Brent and her colleagues published a study in the journal Current Biology on Thursday, describing how older female whales blaze the paths for their sons and, less frequently, daughters to follow.
After around age 35, female orcas lose the ability to have kids, but they can stick around for another 50 years or more. (Most male orcas, on the other hand, have gone to the great salmon feast in the sky by age 50.) Maternal leaders lend valuable experience to their relatives, the scientists say, mimicking the so-called grandmother effect seen in humans. Offering her lifetime of knowledge, grandma can increase the survival of younger members of the group.
Male killer whales "do not live as long as females and have fewer opportunities to obtain information about the environment," Brent said. "This difference in life experience may force males to be more reliant on the ecological knowledge of older females."
Based on 750 hours of footage, filmed over a 9-year span by orca expert Ken Balcomb and the Center for Whale Research, the researchers could identify which orcas regularly swam at the head of the pack. Earlier studies indicate that animals at the front, Brent said, "exert greater influence over the movement of those groups."
Matriarchal guidance is particularly important when food is scarce - which Chinook salmon often are for orcas who live year-round in the Pacific Northwest.
"It seems male orcas are mamas' boys, either for their safety or their food," University College London zoologist Ruth Mace, who was not involved with this study, told New Scientist.
These orcas and short-finned pilot whales are the only whales known to go through menopause the way humans do, Brent said. That emphasizes "just how precious the Southern resident killer whale population is to the scientific community and society as a whole. But with only 79 animals remaining, this endangered population may not be around much longer."