Killer whale mothers ‘pay high price’ for raising sons, study says

Each living son cut a mother’s annual likelihood of successful breeding by about half, researchers say

Having male children makes killer whales less likely to have more offspring, researchers say (Getty)

Raising sons is an exhausting experience that leaves killer whale mothers less likely to produce more offspring, a new study suggests.

Each living son cut a mother’s annual likelihood of successful breeding – a calf surviving to the age of one – by about half, researchers say.

Furthermore, the effect continued as the sons grew older, indicating they were a lifelong burden on their mothers, the scientists said.