Orca-whale and dolphin mothers and their newborns appear not to sleep for a month after the pups' birth, researchers report. Neither parent nor offspring shows any ill effects from the long waking stint, and the animals don't later compensate with extra sleep.
No previously studied mammal stays awake for so long, says Jerry Siegel of the University of California, Los Angeles (UCLA), an investigator in the study.
In the months following their wakeful period, baby whales and dolphins—and their mothers—ramped up slowly to sleep amounts typical of normal adults, Siegel and his colleagues report. The infants' sleep pattern contrasts with that of other mammals, which need extra