Social organisation and population structure of sperm whales off the Galapagos Islands, Ecuador (1985 and 1987)

Models suggest that there are about 15-22 Physeter macrocephalus groups off the Galapagos at any time, with immigration and emigration rates of 1-3.5 groups per month. The groups of females were attended by large male sperm whales 12-16% of the time. Large males (lengths 12.8-16.4m) formed 2-3% of the population, although their abundance varied seasonally. The males moved between groups of females spending c3-6 hr with a group at one time. -from Authors