New research in the journal Scientific Reports shows Northern resident female orca mothers sacrifice so much energy parenting and feeding their male offspring that it drastically reduces their chances of raising another calf again, as their sons are so much needier than daughters. Around eighteen months of pregnancy, up to two years of nursing, then hunting and sharing food with their adult children who never leave, the study is the first time scientists have documented a lifelong toll on mothers in any large mammal species that usually reproduces more than once.
When orca mothers catch large salmon, they feed portions to their infants and sons, even after they are fully grown, for their whole lives! These sons are imposing a cost on their mother, and this is highly unusual, adding to concerns over the orca population’s overall future.
