Dugong and Sea Cow: Dugongidae

Dugongs are semi-social and can be found in units that include the mother and her most recent calf. These pairs have been known to live together in herds of up to hundreds when sea grass is abundant. Not much is known about Steller's sea cow behavior or reproduction.

Female dugongs give birth every three to seven years. The typical pregnancy, which lasts for about one year, usually results in the birth of one calf; twins are rare. The female provides all care for the calf, and nurses, feeds with the mother's milk, until eighteen months to two years of age. Georg Wilhelm Steller, a naturalist and physician who was responsible for the first recorded observations of the sea cow, reported seeing calves year-round, which suggests that mating occurred any time of year. According to Steller's accounts, only single calves were born after a gestation period, pregnancy, of around one year, possibly longer.