Aerial behaviour in sperm whales

Examines the nature and context of breaching (leaping from the water) and lobtailing (thrashing of flukes onto the water surface) in Physeter macrocephalus using data principally collected off the Galapagos Islands. Breaches and lobtails were often found to occur in bouts lasting up to several hours and at times containing >250 individual activities. The rates of observing these activities did not vary seasonally, but breaching was seen more often in 1985 than in 1987, an El Nino year when the whales appeared to have reduced feeding success. Both breaching and lobtailing rates were highest in the late afternoon, although both activities occurred at all times of day and night. Bouts of breaches and lobtails were longer when several groups of sperm whales were together, and during long bouts, groups or small clusters of whales frequently merged or spilt up. Except for 2 breaches, all aerial activity was observed from groups of female and immature whales rather than from mature or maturing males on breeding or feeding grounds. -from Authors