Chordates • Earth.com

West Indian manatee

(Trichechus manatus)

galery

Description

The West Indian manatee (Trichechus manatus) or "sea cow", also known as North American manatee, is the largest member of the aquatic mammal order Sirenia (which also includes the dugong and the extinct Steller's sea cow). It is further divided into two subspecies, the Florida manatee (T. m. latirostris) and the Antillean or Caribbean manatee (T. m. manatus), based on genetic and morphological studies. The Florida subspecies is primarily found along the coasts of Florida, but its range extends as far west as Texas and as far north as Massachusetts. The Antillean subspecies has a sparse distribution throughout the Caribbean, ranging as far north as Mexico and as far south as Brazil. Manatees are obligate herbivores, have developed vocal communication abilities, and are covered in highly sensitive 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. The West Indian manatee was listed as endangered under the Endangered Species Act in the 1970s, when there were only several hundred left, and the decades since have witnessed significant efforts by federal, state, private, and nonprofit organizations to protect these species from natural and human-induced threats, particularly collisions with watercraft. On March 30, 2017, the U.S. Secretary of the Interior Ryan Zinke announced the federal reclassification of the West Indian manatee from endangered to threatened, citing a substantial increase in the total population. 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). Since 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.

Taxonomic tree:

Domain:
Kingdom: Animalia
Phylum:
Class: Mammalia
Order:Sirenia
Family:Trichechidae
Genus:Trichechus
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