User:Alliekohl/Manatee

Communication
== Manatees emit a wide range of sounds used in communication, especially between cows and their calves. Their sounds vary and are complex with a wide variety of tones and frequencies. Their ears are large internally but the external openings are small, and they are located four inches behind each eye. Adults communicate to maintain contact and during sexual and play behaviors. Taste and smell, in addition to sight, sound, and touch, may also be forms of communication. ==

Conservation[edit]
All three species of manatee are listed by the World Conservation Union as vulnerable to extinction. However, The U.S. Fish and Wildlife Service (FWS) does not consider the West Indian manatee to be "endangered" anymore, having downgraded its status to "threatened" as of March 2017. They cite improvements to habitat conditions, population growth and reductions of threats as reasoning for the change. The reclassification was met with controversy, with Florida congressman Vern Buchanan and groups such as the Save the Manatee Club and the Center for Biological Diversity expressing concerns that the change would have a detrimental effect on conservation efforts. The new classification will not affect current federal protections. West Indian manatees were originally classified as endangered with the 1967 class of endangered species.

Manatee population in the United States reached a low in the 1970s, during which only a few hundred individuals lived in the nation. As of February 2016, 6,250 manatees were reported swimming in Florida's springs. It is illegal under federal and Florida law to injure or harm a manatee.

The MV Freedom Star and MV Liberty Star, ships used by NASA to tow Space Shuttle Solid Rocket Boosters back to Kennedy Space Center, were propelled only by water jets to protect the endangered manatee population that inhabits regions of the Banana River where the ships are based.

There are many conservation programs that have been created to help manatees. Save the Manatees is a non-profit group and membership organization that works to protect manatees and their aquatic ecosystems.

Brazil outlawed hunting in 1973 in an effort to preserve the species. Deaths by boat strikes are still common.

Evolution[edit]
Fossil remains of manatee ancestors - also known as Sirenians - date back to the Early Eocene. It is thought that they reached the isolated area of the South American continent and became known as Trichechidae. In the Late Miocene, trichechids were likely restricted in South American coastal rivers and they fed on many freshwater plants. Dugongs inhabited the West Atlantic and Carribbean waters and fed on seagrass meadows instead. As the sea grasses began to grow, manatees adapted to the changing environment by growing supernumerary molars. Sea levels lowered and increased erosion and silt runoff was caused by glaciation. This increased the tooth wear of the bottom-feeding manatees.

Locomotion[edit]
Generally, manatees swim at about 5 to 8 km/h (3 to 5 mph). However, they have been known to swim at up to 30 km/h (20 mph) in short bursts. Manatees use undulatory locomotion by passing a dorso-ventrally wave down the body of the manatee. This active wave travels at a higher velocity than the forward velocity of the manatee. Manatees are able to swim with high efficiencies and lower power outputs. Because of their grazer-like swimming, they are able to successfully seasonally migrate over long distances.

Amazonian[edit]
The freshwater Amazonian manatee (T. inunguis) inhabits the Central Amazon Basin in Brazil, eastern Perú, southeastern Colombia, but not Ecuador. It is the only exclusively freshwater manatee, and is also the smallest. Since they are unable to reduce peripheral heat loss, it is found primarily in tropical waters.

Although countries are protecting the manatees in the locations where they are endangered, there are no enforced laws, which means that the manatees are still being captured throughout the Amazonian areas.

Conservation

Boat collisions cause one quarter of all manatee deaths annually in Florida.