Manatees are large, fully aquatic, mostly herbivorous marine mammals also known as sea cows. There are three living species of manatees, representing three of the four living species in the order Sirenia the Amazonian Manatee , the West Indian Manatee, and the West African Manatee. They measure up to 13 feet long, weigh as much as 1,300 pounds, and have paddle-like flippers. On average, manatees swim at about 3 to 5 mph. However, they have been known to swim at up to 20 mph in short bursts. Manatees typically breed once every two years, gestation lasts about 12 months, and it takes a further 12 to 18 months to wean the calf. Only a single calf is born at a time and aside from mothers with their young or males following a receptive female, manatees are generally solitary creatures. The main causes of death for the manatees are human-related issues, such as habitat destruction and human objects such as boats, fishing nets etc., and natural causes, such as temperatures and disease. Manatees of Chrystal River was filmed by Heiko Kiera aka Ojatro in January 2014.