A new study of killer whales in the North Pacific shows that mothers make ‘life sacrifices’ for their male offspring.

In fact, raising a son greatly reduces the chances of a female whale giving birth in the future.

The energy needed to feed their males appears to compromise their health, making them less able to reproduce and raise other young.

“Orca mothers sacrifice their food and their own energy,” explains Professor Darren Croft from the University of Exeter.

Killer whales maintain close bonds with their families throughout their lives. However, while female children become independent during adolescence, males are still dependent on their mothers, even demanding a share of food from their parent’s occasional prey.

As Professor Croft notes, this multi-year study, published in the journal Current Biology, provides “a new look at the complex social and family life of these magnificent animals.”

“Evolutionary Guarantee”

The study was conducted by the Center for Whale Research (CWR), which has been monitoring the life of a population of killer whales known as “southerners” for more than 40 years.

In this context, scientists studied the lives of 40 female whales between 1982 and 2021 and found that for every living son, a mother’s annual chance of raising another calf before one year is halved.

“Our previous study showed that sons are more likely to survive if their mother is next to them,” the doctor notes. Michael Weiss of the University of Exeter and CWR.

“We wanted to know if this help has a price, and the answer is positive. Killer whale mothers pay a high price in terms of their future breeding to keep their sons alive,” he adds.

According to scientists, this behavior of whales may be a kind of evolutionary “guarantee”, based on the fact that the largest males in size and age become the parents of many offspring.

“If a mother succeeds in making her son an important man in society, then this man will become the father of most of the next generation,” explains Professor Croft.

Since 1976, the CWR has been conducting a complete census of Southerners, which has enabled biologists to conduct such multi-generational studies, shedding light on social behavior and family ties that directly affect animal survival.

It may seem paradoxical and an oxymoron that such strong, intelligent animals remain dependent on their mothers throughout their lives, but males don’t need to be “weaned” as long as their mother stays by their side, researchers say.

Source: BBC