EXHAUSTED parents struggling to deal with a sleepless newborn should spare a thought for dolphin and killer whale mums. Their babies are awake continuously for the first month of their lives, so mum has to stay up too.
Jerome Siegel of the University of California at Los Angeles and his team spotted the surprising 鈥渟leeping鈥� patterns in captive killer whales (Orcinus orca) and bottlenose dolphins (Tursiops truncates). Unlike all animals studied before, which maximise rest and sleep after birth to optimise growth and development, the cetaceans went without shut-eye (Nature, vol 435, p 1177). 鈥淭he idea that sleep is essential for development of the brain and body is certainly challenged,鈥� says Siegel.
Keeping on the go has several advantages. It keeps the infants鈥� body temperature up while they build up a layer of insulating blubber. Plus it keeps them alert to predators. 鈥淚n the water, there鈥檚 no safe place to curl up in,鈥� says Siegel.
Advertisement
