Manatees use their muscular lips to tear plants and guide food to their lips - not unlike the way an elephant uses its trunk. Manatees have a large, double-nostriled snout. Each vibrissa has its own separate follicular blood supply and nerve endings. Manatees can grow over 13 feet in length and weigh up to 3,500 pounds. Their eyes are small, but eyesight is good.
Manatees have a nictitating membrane which can be drawn across the eyeball for protection.
Manatee vocalisations take the form of chirps, whistles and squeaks. Peak energies are in the 3-5 kilohertz range. Communication is particularly frequent between mother and calf, or when the water is turbid. Manatees vocalise to express fear, anger, pain or sexual arousal. They are also adapted to hear infrasound frequencies below 20 hertz.