The average length is 10 feet, and their weight can range from 1,000 pounds to over 3,000 pounds! And yet, despite their bulk, manatees are surprisingly graceful creatures.Manatees are animals that live in water and have been studied for a long time, but we still know little about them. People have thought they were mermaids and sirens for hundreds of years! These secretive creatures have an ethereal mystery that has earned them a mythological reputation.