Manatees have well-developed eyes. In clear water, they can detect objects from tens of yards away. A manatee's retinas contain both rod cells and cone cells, indicating that they may have the ability to see in both dim and bright light. We don't know whether or not manatees can distinguish colors. A nictitating membrane acts as an extra eyelid to protect the eye.
Touch seems to be very important for manatees.
Body contact is common between mother and calf. Manatees have also occasionally been observed initiating body contact with divers. They have even been observed making contact with inanimate objects such as ropes, buoys, logs, and rocks. They have tastebuds on the backs of their tongues and can most likely taste. Studies on manatee food preferences at Blue Springs, Florida indicate that manatees avoid certain plants that contain toxins.