Which mammal order contains manatees and dugongs?

Which mammal order contains manatees and dugongs? The answer is Sirenia.

Sirenia is the mammalian order containing the living manatees and the dugong. These fully aquatic herbivores are often called sea cows because they graze on aquatic vegetation. They inhabit coastal waters, estuaries, rivers, lagoons, and wetlands, depending on the species.

Living sirenians belong to two families. Trichechidae contains three manatee species—the West Indian, Amazonian, and African manatees—while Dugongidae contains the dugong. The extinct Steller’s sea cow also belonged to Dugongidae but disappeared in the eighteenth century, only a few decades after its scientific description.

Sirenia is easy to confuse with Cetacea because both groups are aquatic mammals, but whales and dolphins are predators, whereas sirenians are plant-eaters with paddle-like forelimbs and broad, powerful tails. Another surprising connection is evolutionary: sirenians belong to Paenungulata, the mammalian group that also includes elephants and hyraxes. Their closest relatives are therefore not seals or whales, but these mostly terrestrial African-lineage mammals.