The West Indian manatee (Trichechus manatus), also known as the North American manatee, is a large, aquatic mammal native to warm coastal areas of the Caribbean, from the Eastern United States to northern Brazil. Living alone or in herds, it feeds on underwater plants and uses its whiskers to navigate. It is divided into two subspecies, the Florida manatee (T. m. latirostris) in the United States and the Antillean manatee (T. m. manatus) in the Caribbean, both of which are endangered and face pressure from habitat loss, pollution, and other human activity. The West Indian manatee is the largest living member of the sirenians (order Sirenia), a group of large aquatic mammals that includes the dugong, other manatees, and the extinct Steller's sea cow. Manatees are herbivores, have developed vocal communication abilities, and are covered in highly sensitive whiskers (called vibrissae) that are used for feeding and navigation. In breeding season, several males form mating herds around an individual female; on average, one calf is born to a female manatee every two to three years. In the 1970s, the West Indian manatee was listed as endangered in the United States under the Endangered Species Act, when there were only several hundred left. The decades since have witnessed significant efforts to protect this species from natural and human threats, particularly collisions with watercraft. In 2017, the United States changed the classification to threatened, citing a substantial increase in the total population. In 2025, a petition began by the U.S. Fish and Wildlife Service to reinstate them as endangered.
Description The average West Indian manatee is about 2.7–3.5 m (8.9–11.5 ft) long and weighs 200–600 kg (440–1,320 lb), with females generally larger than males. The largest individual on record weighed 1,655 kg (3,649 lb) and measured 4.6 m (15 ft) long. Manatees are estimated to live 50 years or more in the wild, and one captive Florida manatee, Snooty, lived for 69 years (1948–2017). A captive manatee named Romeo, held at the Gulfarium Marine Adventure Park in Fort Walton Beach, was recognized as the world record holder at 71 years of age in February 2026.
Given that manatees are mammals, they breathe air, have warm blood, and produce milk. Like the other sirenians, the West Indian manatee has adapted fully to aquatic life, having no hind limbs. Instead of hind limbs, the manatee has a spatula-like paddle for propulsion in the water. Manatees have evolved streamlined bodies which lack external ear flaps, thus decreasing resistance in the aquatic environment. Pelage cover is sparsely distributed across the body, which may play a role in reducing the build-up of algae on their thick skin. Manatee skin is gray but can vary in coloration due to algae and other biota, like barnacles, that opportunistically live on manatees. Scar tissue on manatees is white and persists for decades, allowing for easy identification. The Florida manatee has three to four nails on each flipper. The West Indian manatee has a prehensile snout, like their relative the elephant, for grabbing vegetation and bringing it into their mouths. Manatees have six to eight molariform teeth in each jaw quadrant. These molariform teeth are generated at the back of the mouth and slowly migrate towards the front of the mouth, at a rate of 1–2 mm per month, where they then fall out. This tooth 'conveyor belt' provides unlimited tooth production which is beneficial for the manatee which feeds on vegetation four to eight hours per day and consumes 5–10% of its body weight per day. Manatees have 3–5 cm hairs that cover their whole body and provide somatosensory information. Manatee bones are dense and solid which allows them to act as ballast and promote negative buoyancy. This helps counteract the positive buoyancy which comes from their high fat content. These two buoyancy counterparts, along with air in the lungs, helps manatees achieve neutral buoyancy in the water. This makes breathing, foraging, and swimming easier for the manatee. Manatees are unique, compared to other mammals, in that they have a longitudinally oriented diaphragm that is split in half to form two hemidiaphragms. Each hemidiaphragm is capable of independent muscular contractions.
Distribution and habitat The West Indian manatee inhabits mostly shallow coastal areas, including rivers and estuaries. Manatees can withstand large changes in salinity and are found in both freshwater and saltwater. Manatees' extremely low metabolic rate and lack of a thick layer of insulating body fat limits them to locations with warm waters, including tropical regions. The Florida subspecies is primarily found along the Florida coast, but has been spotted as far north as Dennis, Massachusetts, as well as along the Gulf Coast of Texas. Concerning their forays inland, a manatee was once spotted in the Wolf River (near where it enters the Mississippi) in Memphis, Tennessee, in 2006: a distance of over 700 river miles from the Gulf of Mexico. The Antillean subspecies has a sparse distribution throughout the Caribbean, ranging as far north as Mexico and as far south as Brazil. During the Pleistocene, the West Indian manatee had a wider range across North America with fossils being found in Texas, and the Mississippi River and Ohio River. An analysis of mitochondrial DNA patterns indicates there are actually three primary geographic groups of the West Indian manatee: (i) Florida and the Greater Antilles; (ii) Mexico, Central America and northern South America; and (iii) northeastern South America. The seasonal distribution of the West Indian manatee varies with water temperatures. Temperatures below approximately 20 °C (68 °F) increase the risk of cold-induced stress or mortality for manatees. Consequently, Florida manatees seek out warm-water refuges during the winter, concentrated primarily along the Florida peninsula. Many of these refuges are artificial, created by the runoff from nearby power plants. In contrast, the Antillean manatee is less susceptible to cold-induced stress due to the warmer waters across its range.
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