Without the need for group foraging techniques or group defense, this species is largely solitary, occasionally forming loose aggregations. Manatees are not territorial and do not observe any social hierarchy. Most groups are temporary associations, without regard to sex or age. One exception is herds of juvenile males, which are temporary groups that arise from the exclusion of such individuals from reproductive activities. In addition temporary mating herds develop when a female is in estrus.
Manatees use their tail to propel themselves forward and are surprisingly agile in the water.
They are capable of complex maneuvering including somersaults, rolls, and swimming upside-down. They are active day and night, resting for several hours at a time near the surface of the water or at the bottom. While resting on the bottom, they rise to the surface to breath every few minutes. Manatees use various forms of communication in the water. Individuals rub themselves against hard surfaces, possibly secreting a scent to convey information about the reproductive state of the resident females.