Volunteer with West Indian Manatees

Facts about West Indian Manatees

West Indian Manatees are found in coastal areas and are unusual in that they are able to live in both fresh and saltwater environments.  These gentle giants are curious animals and particularly friendly individuals often swim up to divers and snorkelers!  Manatees are such beautiful and graceful animals that in times gone by, sailors regularly mistook them for mermaids!

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A West Indian Manatee in Florida. Photo credit: USFWS, Flickr

Fast Facts
Scientific name:
Trichechus manatus
Habitat / Distribution:Coasts, estuaries and rivers / South-eastern US, Central and South America.
Length range:Up to 4.1m

Lifespan:60-70 yrs

Diet:Aquatic and semi-aquatic vegetation. May occasionally take fish from nets.
Predators:Humans (illegal poaching).
Reproduction:Usually give birth to one calf.
IUCN Conservation Status:Vulnerable

A curious baby manatee swims with some snorkellers in Florida.

West Indian Manatee classification and identification

Manatees belong to a group called the Sirenians, which includes the dugongs and all four extant species of manatee.  Sirenians have been around for over 50 million years and share common ancestors with elephants and mammoths.  Indeed, manatees still share many characteristics with elephants that provide evidence of their evolutionary past.  These include a tough, thick skin that is sparsely covered in hair and an unusual spherical shaped heart.

Sirenians, also referred to as sea cows, are large, slow-moving, aquatic mammals.  They are torpedo shaped and have no hind limbs but are able to maneuver themselves by using their front flippers as paddles.  They generally graze on aquatic plants as a source of food and have a large number of replaceable molar teeth to compensate for this abrasive diet.

West Indian manatees can be identified as large, gray, aquatic mammals with bodies that taper to a flat, paddle-shaped tail.  They have two forelimbs, called flippers, with three to four nails.  Their head and face are wrinkled with whiskers on the snout.  As there are no other species of Sirenian living in the Caribbean, if you see one there you can be pretty confident it’s a West Indian Manatee!  There are two sub species of West Indian Manatee, namely the Florida Manatee, which is found in the US, and the Antillean Manatee, which inhabits the remainder of the Caribbean and South American range of the species.
The word Sirenia comes from the word siren.  Sirens are legendary Greek sea beauties from Homer’s Odyssey that lured sailors into the sea.  It is thought that old-time mermaid sightings were actually Sirenians rather than mythical half women, half fish.  The word manatee originates from a Carib word for “breast or “udder”, while the West Indian Manatee was named after the area in which it inhabits.

West Indian Manatee adaptations

Manatees generally surface every 3-5 minutes to breath, but are capable of remaining submerged for up to 20 minutes at a time.  They typically live in shallow waters and have not been known to dive to significant depths.

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A diver swims with a West Indian Manatee. Photo credit: Greg Amptman, Shutterstock

Where do West Indian Manatees live?

West Indian Manatees can move freely between fresh and seawater which is unusual for marine mammals.  They seem to prefer rivers with true grasses or calm estuarine environments where seagrasses are plentiful.  Florida manatees spread out along their entire range in summer, but will retreat to warmer Floridian waters in the winter months.  Such is their love for warm water that they are known to congregate in areas where industrial facilities discharge heat into the water.  Areas of high energy coastline where there is little or no submerged vegetation are largely devoid of manatees.

How big are West Indian Manatees?

Males can measure up to 3.7m long while females are slightly larger, reaching lengths of up to 4.1m.  West Indian Manatees are one of the true heavyweights of the animal kingdom, weighing in at a scale shattering 1,400 kg!

How long do West Indian Manatees live?

The lifespan of a wild West Indian Manatee is typically in the region of 60-70 years.

What do West Indian Manatees eat?

These tranquil beasts graze on a huge variety of aquatic and semi-aquatic vegetation, and occasionally even plants on river banks that lie within reach of the water.  In Jamaica, there are reports that, on rare occasions, they have taken fish from nets.

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A baby West Indian Manatee.     Photo credit: Jacinta Iluch Valero (CC BY-SA 2.0), Flickr

What eats West Indian Manatees?

West Indian Manatees have no natural predators, but are sometimes hunted illegally by humans.

West Indian Manatee life cycle and reproduction

Manatees are capable of breeding year round, although calves are most typically born between March and August.  A mating herd of males will assemble and vigorously compete with one another for a position close to a female.  Following copulation, females give birth after 12-14 months of gestation.  Twins are uncommon, but do occur occasionally.  The female will then wean the newborn calf for a period of around 18 months.  Male manatees are not involved in parenting their young.  Normally there is an interval of about 2.5 years between calves.

Are West Indian Manatees endangered and if so why?

The World Conservation Union (IUCN) lists the West Indian Manatee as Vulnerable.  This is because the current population of below 10, 000 individuals is declining slowly.  Coastal developments have resulted in a loss of habitat, while half of all adult mortalities are as a result of collisions with boats.

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