Menopause for killer whales involves mother-daughter conflict: study
VICTORIA — Mother-daughter conflicts rooted in a tug-of-war between competition and co-operation are helping explain why killer whales go through menopause, says a study released Thursday.
Killer whales are one of only three species, including humans, who go through menopause. The animals often live for decades after giving birth to their final calves and are relegated to adopting roles for their pods as grandmothers and wise elders who know where to search for food.
Prof. Darren Croft of the University of Exeter in England led the new study, which used 43 years of data gathered by whale researchers at Canada’s Department and Fisheries and Oceans on the West Coast and the Center for Whale Research in the United States at Friday Harbor, Wash. The study was published in the journal Current Biology.
Croft, who has spent time in the Salish Sea on both sides of the border near Vancouver Island observing the animals, said scientists have long considered why killer whales who stop having calves in their 30s and 40s have lifespans into their 80s, 90s and beyond. Researchers wondered what prevents the whales from continuing to reproduce during their lifespans.