Lifespan, Mortality, Population: West Indian manatees have no natural enemies, and it is believed they can live 60 years or more. As with all wild animal populations, a certain percentage of manatee mortality is attributed to natural causes of death such as cold stress, gastrointestinal disease, pneumonia, and other diseases. A high number of additional fatalities are from human-related causes. Most human-related manatee fatalities occur from collisions with watercraft. Other causes of human-related manatee mortality 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, loss of habitat is the most serious threat facing manatees in the United States today. There is a minimum population count of 4,480 manatees, as of January 2011.

   Breeding and Reproduction: The reproductive rate for manatees is low. Manatees are not sexually mature until they are about five years old. It is believed that 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, during which time a calf remains dependent on its mother.

   Legal Protection: West Indian manatees in the United States are protected under federal law by the Marine Mammal Protection Act of 1972, and the Endangered Species Act of 1973, which make it illegal to harass, hunt, capture, or kill any marine mammal. West Indian manatees are also protected by the Florida Manatee Sanctuary Act of 1978. Violations of these federal or state laws can be met with civil or criminal convictions associated with monetary fines and/or imprisonment.