West Indian manatee (Trichechus manatus)

Kingdom: Animalia

Class: Mammalia

Order: Sirenia

Family: Trichechidae

Listing Status:   

Quick links:Federal RegisterRecoveryCritical HabitatConservation PlansPetitionsLife HistoryOther Resources

General Information

Manatees are marine mammals found in marine, estuarine, and freshwater environments. The West Indian manatee, Trichechus manatus, includes two distinct subspecies, the Florida manatee (Trichechus manatus latirostris) and the Antillean manatee (Trichechus manatus manatus). While morphologically distinctive, both subspecies have many common features. Manatees have large, seal-shaped bodies with paired flippers and a round, paddle-shaped tail. They are typically grey in color (color can range from black to light brown) and occasionally spotted with barnacles or colored by patches of green or red algae. The muzzle is heavily whiskered and coarse, single hairs are sparsely distributed throughout the body. Adult manatees, on average, are about nine feet long (3 meters) and weigh about 1,000 pounds (200 kilograms). At birth, calves are between three and four feet long (1 meter) and weigh between 40 and 60 pounds (30 kilograms).

• States/US Territories in which the West Indian manatee is known to occur:  Florida , Georgia , Puerto Rico , Texas
• USFWS Refuges in which the West Indian manatee is known to occur:  ACE BASIN NATIONAL WILDLIFE REFUGE , BLACKBEARD ISLAND NATIONAL WILDLIFE REFUGE , CHASSAHOWITZKA NATIONAL WILDLIFE REFUGE , CRYSTAL RIVER NATIONAL WILDLIFE REFUGE , HARRIS NECK NATIONAL WILDLIFE REFUGE ISLAND BAY NATIONAL WILDLIFE REFUGE , J.N. 'DING' DARLING NATIONAL WILDLIFE REFUGE , LAKE WOODRUFF NATIONAL WILDLIFE REFUGE , LOWER SUWANNEE NATIONAL WILDLIFE REFUGE , MATLACHA PASS NATIONAL WILDLIFE REFUGE , MERRITT ISLAND NATIONAL WILDLIFE REFUGE , PELICAN ISLAND NATIONAL WILDLIFE REFUGE , PINE ISLAND NATIONAL WILDLIFE REFUGE , PINELLAS NATIONAL WILDLIFE REFUGE , SAVANNAH-PINCKNEY NATIONAL WILDLIFE REFUGES , ST. MARKS NATIONAL WILDLIFE REFUGE , TEN THOUSAND ISLANDS NATIONAL WILDLIFE REFUGE , VIEQUES NATIONAL WILDLIFE REFUGE , WOLF ISLAND NATIONAL WILDLIFE REFUGE  ... Show All Refuges
  
• Countries in which the the West Indian manatee is known to occur:  Mexico
• For more information:  http://www.fws.gov/endangered/factsheets/manatee.pdf

» Federal Register Documents

» Recovery

• Information Search FAQs

» Critical Habitat

To learn more about critical habitat please see http://criticalhabitat.fws.gov

» Conservation Plans

No conservation plans have been created for West Indian manatee

» Petitions

No petition findings have been published for the West Indian manatee.

» Life History

Habitat Requirements

Florida and Antillean manatees range freely between marine and freshwater habitats. Specific habitat types/use areas include foraging and drinking sites, resting areas, travel corridors and others. Florida manatees, living at the northern limit of the species' range, have little tolerance for cold. Historically, this sub-species has sought out natural, warm-water sites, including springs, deep water areas, and areas thermally influenced by the Gulf Stream, as refuges from the cold. In the 1930s and 40s, industrial plants, including power plants, paper mills, etc., were built along coastal and riverine shoreline areas. Plants discharging large volumes of heated discharge water into areas accessible to manatees have attracted large numbers of wintering manatees to these warm-water sites ever since. In the spring, manatees leave the warm-water sites and may travel great distances during the summer, only to return to warm water sites in the fall.

Food Habits

Manatees are herbivores that feed opportunistically on a wide variety of marine, estuarine, and freshwater plants, including submerged, floating, and emergent vegetation. Common forage plants include and are not limited to: cord grass, alga, turtle grass, shoal grass, manatee grass, eel grass, and other plant types. (Calves initially suckle and may start feeding on plants when a few months of age. Weaning generally takes place within a year of birth.) Manatees also require sources freshwater, obtained from both natural and anthropogenic sources.

Movement / Home Range

The Florida manatees' range is generally restricted to the southeastern United States; individuals occasionally range as far north as Massachusetts and as far west as Texas. Antillean manatees are found in coastal and riverine systems in South and Central America (from Brazil to Mexico) and in the Greater and Lesser Antilles throughout the Caribbean Basin. Due to a variety of human activities (hunting, loss of habitat, etc.), manatees have been extirpated from many areas and their distribution is patchy throughout the region. USFWS recovery activities primarily focus on manatees in Florida and Puerto Rico, although the species is managed throughout its range.

Reproductive Strategy

Manatees mature at three to five years of age. Mature females go into heat for anywhere from two to four weeks. Mating activity can occur throughout the year. When in heat, females will attract numerous males and mate repeatedly; aggregations that include an estrus or focal female and numerous males are described as mating herds. Gestation lasts for about 13 months and cows usually give birth to a single calf; twinning is known to occur. While calving primarily peaks in the spring, calves may be born at any time of the year. Reproductive senescence is poorly described; a known female has given birth to seven individual calves over a period of about 30 years. A calf may remain with its mother for about two years. Calving intervals range from two and three years. The oldest known manatee is 61 years of age.

Other

Per a 2009 survey, there are at least 3800 Florida manatees; Antillean manatees in Puerto Rico are thought to include about 350 animals. Both stocks are thought to be stable and perhaps increasing in certain areas. Survival and reproductive rates are generally positive, even in the face of increasing human-related threats, including watercraft, habitat loss, and other activities.

» Other Resources

NatureServe Explorer Species Reports -- NatureServe Explorer is a source for authoritative conservation information on more than 50,000 plants, animals and ecological communtities of the U.S and Canada. NatureServe Explorer provides in-depth information on rare and endangered species, but includes common plants and animals too. NatureServe Explorer is a product of NatureServe in collaboration with the Natural Heritage Network.

ITIS Reports -- ITIS (the Integrated Taxonomic Information System) is a source for authoritative taxonomic information on plants, animals, fungi, and microbes of North America and the world.