Diving behaviour of the sperm whale, Physeter macrocephalus, off the Galapagos Islands

At depths of <300 m the whales generally dived nearly vertically at 60-100 m/min. At greater depths their descents were usually slower. Between February and April 1985, they dived to c420 m, around the depth of the oxygen minimum. In 1987, a year of warmer water temperatures, they usually dived about 70 m shallower. There was no apparent diurnal variation in dive depths. Whales dived for c40 min, followed by 10 min at the surface. Sperm whales usually started to make regular clicks when 150-300 m deep. Young calves appeared not to make prolonged deep dives. -from Authors