Since sperm whales can find resources in almost any ocean and these resources are not defensible, they occupy large home ranges. Sperm whales cluster into what have been labeled schools, pods, herds, or bodies. All of these descriptions refer to groups of whales that are moving together, for at least a few hours, in a coordinated fashion.

Units function in the same manner as these groups except that units stay together for periods of years, although they can split, transfer, or merge. Clans consist of multiple groups which can contain many units. Overlapping clans in the South Pacific contain 10,000 whales (Whitehead and Rendell, 2004). Groups and units vary depending on location (Whitehead, 2003). The average number of individuals in a unit of related females and their male and female offspring is 10 individuals. Units of females and their offspring off the coast off the Galapagos Islands generally consist of 10 individuals with 2 matrilines (Coakes and Whitehead, 2004). In the Eastern Tropical Pacific, females and their offspring live in units of 12 and join with other units of their clan to form groups for durations of 7 to 10 days (Jaquet et al, 2003). The oldest females seem to have leadership in units but there is no evidence of traditional hierarchies (Norris and Dohl, 1980).

Male sperm whales leave their natal group at sexual maturity to join bachelor groups, becoming more solitary as they grow in size. Mature male sperm whales rove alone or come together in loose aggregations (Connor, 2002). The largest males tend to remain solitary (Matthews, 1974). Aggregations of males do not appear to have any leadership (Norris and Dohl, 1980). During the summer months, some aggregations of mature males tend to swim to higher latitudes where there is cooler water rich with nutrients. Females stay with their offspring in more temperate waters (Minasian et al, 1984). Aggregations of males, although not social, must have some reason for moving together. It could be that they are following a school of prey or increasing their foraging success by group foraging, using each other for information, catching prey that have escaped from each other, or avoiding competition with other aggregations (Whitehead, 2003).

These units of related females and their young most likely developed because they get protection, support, and information from each other long-term. Male sperm whales are so large that predation pressure is low and because they do not participate in natal care, they would not benefit from living socially.