<P> Manatees are large marine mammals that inhabit slow rivers, canals, saltwater bays, estuaries, and coastal areas . They are a migratory species, inhabiting the Florida waters during the winter and moving as far north as Virginia and as far west as Texas in the warmer summer months . Manatees are calm herbivores that spend most of their time eating, sleeping, and traveling . They have a lifespan of about 60 years with no known natural enemies . Some of their deaths are the result of human activity . In the past, manatees were exploited for their meat, fat, and hides . </P> <P> Various human activities threaten manatee populations . Fishing nets and lines can cause injuries to manatees that can lead to serious infections . Some manatee deaths are the result of collisions with boats . Additionally, coastal development can affect manatee habitats, both positively and negatively . Manatees tend to gather in the warm water outflows of power plants and springs during cold weather . </P> <P> Starting in the 18th century when the English declared Florida a manatee sanctuary and made manatee hunting illegal, people have worked to protect this species . In 1893, manatees first received protection under Florida law, and in 1907 this law was revised to impose a fine of $500 and / or six months of jail time for molesting or killing a manatee . In accordance with the Endangered Species Preservation Act of 1966, an act of Congress designed to list endangered animal species and offer them limited protection, the manatee became one of 78 original species listed as being threatened with extinction . There are currently more than 1300 species on this list . On March 11, 1967 federal efforts to protect the manatee began when the United States Fish and Wildlife Service listed the manatee as endangered . </P> <P> In 1972, the manatee was designated a marine mammal protected under the Federal Marine Mammal Protection Act . This act prohibited the removal of any marine mammal and imposed a fine of up to $2000 and / or one year in jail for doing so . The Endangered Species Act of 1966 was revised in 1973 and increased federal protection of manatees . The "act made it a violation to harass, harm, pursue, hunt, shoot, wound, kill, capture, or collect an endangered species...authorized cooperative agreements between states and the federal government with funding management, research and law enforcement ." </P>

When were manatees put on the endangered list