West Indian Manatee

Scientific Name: Trichechus manatus

Manatee SwimmingDescription: Sometimes known as “sea cow” because it forages on aquatic plants, the West Indian manatee is one of four living species of the aquatic mammal order Sirenia. There are two subspecies of West Indian manatee—the Florida manatee (Trichechus manatus latirostris) and the Antillean manatee (Trichechus manatus manatus). The two share many traits in common. They are most often grey in color but can range from black to light brown. Their wrinkled skin is covered sparsely with hairs and is sometimes spotted with algae or even barnacles. They have large, heavy, seal-shaped bodies with paired flippers, and a round, paddle-shaped tail. Their faces are wrinkled and bear whiskers. Their upper lip is flexible and split and used to pass food into the mouth. Despite their large size, they are very agile in the water. They spend most of their time underwater but return to the surface to breathe, often remaining just below the surface with only their snouts peaking out above the water. They can remain underwater for as long as 12 minutes, but the average is 4-1/2 minutes.

Size: At birth, calves are between three and four feet long and weigh anywhere between 40 and 60 pounds. Once they reach adulthood manatees average 10 feet in length and weigh between 800 to 1,200 pounds.

Diet: Manatees eat aquatic plants such as cordgrass, turtle grass and eelgrass and even non-native water hyacinth and hydrilla. They consume anywhere from four to nine percent of their body weight each day, which averages to about 32 pounds of plants a day. They spend about 5 to 8 hours eating each day. They can use their flippers to dig up plants and use their upper lip to manipulate leaves of plants for feeding. They also occasionally eat invertebrates and fish.

Predation: The West Indian manatee has no natural predators.

Typical Lifespan: The average lifespan is 30 years in the wild.

Habitat: West Indian manatees prefer shallow, slow-moving waters of rivers, estuaries, saltwater bays, canals and coastal areas. They can move easily between freshwater and saltwater environments, but prefer freshwater.

Range: Florida manatees are found primarily along the coast of Florida, the Gulf Coast and the Caribbean. They migrate between winter grounds in the Caribbean and Florida and summer grounds which can be as far north as North Carolina and as far west as Texas, although they have been spotted as far north as Rhode Island. They have little tolerance for cold water because of their low metabolism and lack of insulating body fat. Antillean manatees are found in the Caribbean, in the Gulf and Caribbean coasts of Central America, and in northern and eastern South America.

Life History and Reproduction: With no breeding season, manatees can mate at any time of the year. Females reach sexual maturity between three to ten years of age and will give birth to one or two calves young every 2-5 years. The calves nurse underwater from a nipple behind the mother’s forelimb. They can start eating plants right away, but will continue to stay with their mothers and nurse for up to two years.

Communication: They communicate with touch and with vocalizations that sound like squeals and squeaks. Mother and calf recognize each other through these vocalizations which help them to remain in contact. 

Fun Fact: Sailors once mistook manatees for mermaids. The scientific name for the zoological order manatees belong to, Sirenia, comes from the word “siren,” a legendary beautiful sea creature from Greek mythology whose songs lured sailors to shipwreck.

Conservation Status: Manatees were hunted historically but now are protected under the Marine Mammal Protection Act, which prohibits the take of all marine mammals. Today the biggest threats to manatee survival are collisions with boats and loss of warm water springs that provide important habitat, but they are also vulnerable to entanglement in fishing gear, red tide blooms and loss of seagrass beds they feed upon due to pollutants. They are considered endangered and their survival is seen as limited due to their low reproductive rates.

Sources:

IUCN Red List of Threatened Species
NatureServe Explorer
Ranger Rick Kids
Sirenian International
Society for Marine Mammology
U.S. Fish & Wildlife Service Manatee Fact Sheet
U.S. Fish & Wildlife Service Manatee Species Profile

Additional Resources:

Making Sense of Manatees, National Wildlife Magazine
Manatee Adaptations, Journey North
Toxic Algae: Florida's Manatees in Crisis, Wildlife Promise

Videos:

ARKive--several videos of West Indian manatees
Discovery Channel, Animals of North America
Manatee Anatomy, NOAA Ocean Today
National Geographic Kids


 

 

 

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