The manatee has small eyes, protected by membranes which can be drawn across the eyeballs. The manatee is capable of seeing in both dim and bright lighting, and can probably see colors, but has somewhat limited depth perception. It produces thick, sticky tears to protect its eyes when they are out of the water. Although the manatee lacks eyelids as we know them, it can still blink to protect its eye. The ears of the manatee are internal, with no external lobes, but the underwater hearing of the animal is quite good.
Manatees produce squeaks and chirps.
It is not known for sure why, but it is suspected that they could range from alarm calls, to expressions of happiness. Most scientists believe that the manatee does not use these sounds for echolocation like a dolphin would. Breathing occurs through a pair of nostrils located on the top of the nose. The manatee can close off its nostrils when diving in order to keep water out. This allows the manatee to make more efficient use of its trips to the surface.