Manatee Information Sheet

Name: West Indian manatee, Trichechus manatus

Status: Federally listed Endangered Species

About Manatees:

Manatees are large, gentle, herbivorous, slow moving mammals. They are entirely aquatic, and biologists classify them in a distinct group comprising only 2 families and 3 living species. The major threats to manatee survival are human activities: boat-related injuries and deaths, habitat loss or degradation, and in some countries, hunting.

• Manatees and their closest relative, the dugong, are in the Order Sirenia; their ancestors evolved from four-footed land mammals over 60 million years ago.
• Manatees are more distantly related to elephants and hyraxes; the latter are small mammals native to Asia and Africa.
• They range in color from gray to brown, and the average adult is about 10 feet long and weighs between 1,500 and 2,200 pounds. Life expectancy is about 60 years.
• Female manatees typically start to reproduce at 4 to 5 years of age.
• The gestation period is 11 to 13 months; twin births occur occasionally.
• Newborns range in size from 4 to 4.5 feet, and weigh about 60 pounds.
• Calves are dependent on their mother for up to 2 years; nursing takes place underwater.

Distribution and Habitat Requirements:

• Geographic range includes the southeastern United States, the Caribbean Islands, eastern Mexico and Central America, and the northern coast and rivers of South America.
• There are two subspecies: the Florida manatee (T. m. latirostris) and the Antillean manatee (T. m. manatus).
• The range is limited by temperature. Manatees cannot survive for extended periods in water colder than about 17°C (63°F), and prefer temperatures warmer than 22°C (72°F).
• Manatees live in shallow fresh, brackish and marine aquatic habitats, traveling readily among them. In Florida, they travel considerable distances during the winter to access warm water refugia, such as artesian springs and the heated discharges of power generating plants. Some individuals also travel long distances during the warm season.

USGS Manatee Research:

USGS works in partnership with other Federal and State agencies and private organizations to study manatee life history, behavior, ecology, and population biology. This information is vital to the U.S. Fish and Wildlife Service, the U.S. Navy, the National Park Service, the Marine Mammal Commission, and Florida and Georgia natural resource managers for the successful implementation and assessment of Florida manatee population recovery plans. USGS utilizes satellite telemetry and global positioning system technology, a digital image-based catalog of individual manatees identified by their unique scars, genetic analysis and microhistology to study:

• Movement patterns and identification of significant habitats
• Reproduction and survival
• Population status and trends
• Population structure
• Diets of manatees in high-use habitats

Printable Information Sheet (530 kb PDF file)