How Do Manatees Sleep?

Manatees are gentle giants of the ocean, shy mammals who have in the past been mistaken as mermaid by confused sailors. Despite their portly bodies and scrunchy, whiskered faces, manatees bear the Latin name "sirenia" which means mermaid, or siren. Manatees are herbivores that often lounge just below the surface when resting, just on the line of sight for sailors looking down into the water. Perhaps lonely sailors, far from home and not having seen a woman's form for months if not years, could have confused their sleeping forms for a woman.

  1. Natural History

    • Manatees are a large, gray aquatic mammal whose closest two relatives are the elephant and the hyrax, a small gopher-sized mammal. It is believed that manatees evolved from a wading, plant-eating mammal. Since they are so large, they spend most of their time resting and eating, floating just below the surface, since they must come up for air every three to five minutes. When they are fully resting, they can stay submerged for up to 20 minutes. For this reason, manatees do not sleep for extended periods, but instead take many "naps" during the day.

    Habitat and Location

    • Although they are warm-blooded mammals, manatees must stay in fairly warm waters. They are generally found off coastal waters in the tropics. During the summer, West Indian Manatees are known to be found as far north as the coast of Massachusetts, though sightings along the Georgia, Alabama and South Carolina coasts are more common. They are usually a common sight off the coast of Florida. When submerged and resting, manatees are generally either just under the surface of the water, or they may stay at the bottom.

    Diet

    • Manatees are vegetarians, eating a variety of sea grasses, floating plants and other aquatic plant life. They may eat up to 10 to 15 percent of their body weight in vegetation each day. Manatees are notoriously slow movers, swimming only about three to five miles an hour, although they can maintain short bursts of speed of up to 20 miles an hour.

    Predators

    • Manatees have no natural predators. Although sometimes old or weak ones are eaten by alligators or sharks, this is a rare occurrence. Their greatest threat is by loss of habitat, and being killed by motorboat blades when boat motorists who fail to see the sleeping giants who lay just beneath the surface of the water run them over. Manatees can also drown when they become entangled in fishing lines while submerged, which prevents them from surfacing for air.

    Conservation

    • Today manatees are recognized as an endangered species and are protected under the Endangered Species Act of 1973 and the Marine Mammal Protection Act of 1972. The West Indian manatees of the United States are also protected under the Florida Manatee Sanctuary Act of 1978. Motorists close to shore are required to go slow to avoid hitting the slumbering manatees as they rest and eat close to shore where vegetation is plentiful and the water is warm.