Parenting is No Easy Task... Whales Flip Their Bellies to Rest

A study suggests that mother whales adopting an unusual posture of flipping their bellies upward to float on their backs may be a rest strategy to recover energy while nurturing calves. Researchers from the University of Western Australia observed this behavior in the 'Head of the Bay' marine protected area of southern Australia. Using drones, they tracked 59 mother-calf pairs from June to September 2021, finding that mothers spent about 33% of their day resting, with longer rest periods during the early days after giving birth. Notably, 25% of the mothers floated on their backs with bellies exposed, a behavior never before documented in large whales. Analysis of 75 hours of video revealed this behavior occurred exclusively in nursing mothers, with the flipped position preventing calves from accessing the nipple, thereby reducing nursing time and conserving energy. Longer rest periods correlated with shorter nursing sessions.