West Indian manatees, Trichechus manatus (aka Florida manatees) are large, grayish-brown, aquatic mammals. They range from 10 to 12 feet in length and weigh between 800 and 3,500 pounds. Manatees have two pectoral fins (modified arms) and a flat, rounded tail. Their closest living relative is the elephant. They are one of four remaining species of the order Sirenia, which also includes the West African manatee, the Amazonian manatee, and the dugong.

Manatees are migratory animals who depend upon water temperatures above 68ºF for survival. During the summer months, as water temperatures rise, manatees may travel up to 25 miles a day, reaching territory as far west as Louisiana and as far north as Rhode Island. They can endure fresh water, salt water, and brackish habitats. They live in shallow, warm, coastal waters, as well as rivers, springs, bays, estuaries, canals, and warm water outfalls.

Manatees are gentle and slow moving. They graze for aquatic plants along the water's bottom and on the surface, consuming as much as 10 to 15% of their body weights daily. Manatees may rest submerged at the bottom or just below the surface, coming up to breathe on the average of every three to five minutes. Manatees emit sounds underwater to communicate. These sounds—chirps, whistles, or squeaks—may communicate fear, anger, or sexual arousal.

Manatees produce one offspring every two to five years. After a 14-month gestation period, mothers nurse their young, remaining the dependent calves for up to two years. At birth, manatee calves are three to four feet long and weigh 60 to 70 pounds. Females are not sexually mature until five to nine years. Under favorable conditions, manatees may live more than 60 years.

Manatees have no natural enemies except humans. Today the manatee population is thought to number approximately 3,200 individuals. They are listed as "endangered" by the Endangered Species Act.