West Indian manatees are 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. The manatee’s closest land relatives are the elephant and the hyrax, a small, gopher-sized mammal. Manatees are believed to have evolved from a wading, plant-eating animal. The West Indian manatee is related to the West African manatee, the Amazonian manatee, the dugong, and to the Steller’s sea cow, which was hunted to extinction in 1768. The average adult manatee is about three metres (9.8 feet) long and weighs between 362-544 kilogrammes (800-1,200 pounds).
Manatees can be found in shallow, slow-moving rivers, estuaries, saltwater bays, canals and coastal areas. Manatees are a migratory species.
Manatees are gentle and slow-moving. Most of their time is spent eating, resting, and in travel.
Manatees are completely herbivorous. They eat aquatic plants and can consume 10-15% of their body weight daily in vegetation. They graze for food along water bottoms and on the surface. They may rest submerged at the bottom or just below the surface, coming up to breathe on the average of every three to five minutes. When manatees are using a great deal of energy, they may surface to breathe as often as every 30 seconds. When resting, manatees have been known to stay submerged for up to 20 minutes.
West Indian manatees have no natural enemies, and it is believed they can live 60 years or more.
Many manatee mortalities are human-related. Most human-related manatee mortalities occur from collisions with watercraft. Other causes of human-related manatee mortalities include being crushed and/or drowned in canal locks and flood control structures; ingestion of fish hooks, litter and monofilament line; and entanglement in crab trap lines. Ultimately, however, loss of habitat is the most serious threat facing manatees today.
The reproductive rate for manatees is slow. Female manatees are not sexually mature until about five years of age, and males are mature at approximately nine years of age. On average, one calf is born every two to five years, and twins are rare. The gestation period is about a year. Mothers nurse their young for one to two years, so a calf may remain dependent on its mother during that time.