Trichechus
Trichechus is a genus of large, fully aquatic mammals commonly known as manatees. They are herbivores, feeding primarily on aquatic plants, and are found in tropical and subtropical waters of the Americas, Africa, and the Caribbean. Manatees are distinguished from their closest relatives, dugongs, by their round, paddle-shaped tails, and their lack of hind limbs. The three extant species of manatees are the West Indian manatee (Trichechus manatus), the Amazonian manatee (Trichechus inunguis), and the African manatee (Trichechus senegalensis). The latter two species are more closely related to each other than to the West Indian manatee.
Characteristics
Manatees are large, slow-moving mammals with thick, gray skin and a rounded body. Their front limbs are modified into flippers, and they have a large, paddle-shaped tail. Adult manatees typically weigh between 400 and 1,500 kg (880-3,300 lb) and can grow to lengths of 2.5-4 m (8-13 ft). Their lifespan is about 50 years.
Manatees have a number of adaptations for their aquatic lifestyle, including nostrils located on the top of their heads, which allow them to breathe while submerged, and small, hairless ears. They are able to hold their breath for up to 20 minutes, although they typically surface for air every 3-5 minutes.
Manatees are herbivores, and their diet consists primarily of aquatic plants, such as grasses, algae, and water hyacinths. They are slow-moving and not very aggressive, feeding for 6 to 8 hours each day. Their digestive system is adapted to break down tough plant matter, and they can consume up to 10% of their body weight in vegetation daily.
Environment
Manatees are found in a variety of aquatic habitats, including rivers, estuaries, coastal waters, and lagoons. They prefer warm waters, and their distribution is limited by cold temperatures. Manatees are social animals, and often congregate in groups of 2-10 individuals, though these groups can reach 100 in the winter during cold snaps.
The West Indian manatee is found along the coasts of the southeastern United States, the Caribbean, and Central and South America. The Amazonian manatee is found in the Amazon River basin of South America, and the African manatee is found in rivers and coastal waters of western and central Africa.
Conservation Status
All three species of manatees are classified as either Vulnerable or Endangered by the IUCN Red List. Manatees are threatened by a number of factors, including habitat loss, boat collisions, fishing gear entanglement, and water pollution. They also face threats from climate change and the emergence of new diseases.