Sirenians are a group of aquatic mammals that belong to the order Sirenia. They have a large, rotund body shape and a large head, with two flippers for forelimbs and a tail that is usually rounded and hairless.
They can range in size from around 2.5 m (8.2 ft) and 400 kg (882 lbs) for smaller species like the West Indian manatee, to around 4.5 m (14.8 ft) and 590 kg (1,300 lbs) for the larger species such as the dugong. They have thick, gray or brown skin, and their front flippers have nails on the tips of the fingers.
Sirenians are found in warm coastal waters and rivers in the Caribbean, Gulf of Mexico, and the Amazon basin in South America, as well as the Indian and western Pacific Oceans.
They prefer shallow, seagrass-rich habitats such as bays, lagoons, and estuaries, and are also known to occupy a wide variety of freshwater, brackish and saltwater habitats, including mangrove swamps and freshwater rivers.
Sirenians are herbivores and feed mainly on seagrass and other aquatic plants, along with fruits and mangrove leaves. They use their incisors and molars to chew and grind the plants.
Sirenians are generally slow-moving and peaceful animals. They are known to be curious and can be approached by humans, but are solitary creatures, occasionally forming small groups during the mating season.
They are able to hold their breath for a significant amount of time and spend most of their time submerged, coming to the surface to breathe.
Sirenians is an order containing two extant families: Trichechidae (manatees) and Dugongidae (dugongs) and one extinct family: Protosirenidae. Sirenians have only 4 extant species: the West Indian manatee, the Amazonian manatee, the West African manatee and the Dugong.
Sirenians are considered vulnerable as a whole, mainly because of human activities, such as habitat loss and degradation, hunting, and accidental death from boat collisions. Conservation efforts include protected areas, hunting bans, and public awareness campaigns to reduce collisions with boats.