(Photo © David R. Schrichte)

True or false: manatees hear and see well.

If you answered false, don’t worry -- you’re in the majority. Many people think manatees are lacking a little when it comes to these two senses. This is probably because manatees have small eyes and their ears are…well, where are their ears anyway? But the answer to the question is actually true. Surprised? Read on.

Like elephants, their closest land relatives, manatees have small, button-like eyes. But amazingly, they have fairly good vision. Scientists have found that manatees can distinguish between different-sized objects, colors, and patterns. Another neat thing about manatees is they have what is called a “nictitating membrane” that can be drawn across their eyeball to protect it.

And although they aren’t easy to spot, manatees have two tiny ear openings that are located just behind their eyes. Even though they don’t have external ears like humans, researchers still think manatees may have a good sense of hearing. This is because manatees have extremely large ear bones. In addition, their ear bones make direct contact with their cheekbones, which are also quite large and oily and may aid in receiving and conducting sound.

Click here to listen to vocalizations between a mother and calf. Notice the difference in pitch. (Photo © Walker Stanberry)

Manatees also communicate with one another, making sounds underwater that can be described as chirps, whistles, or squeaks. Scientists don’t believe that manatees use sound for navigational purposes. Their vocalizations may express fear, anger, or sexual arousal. Manatees also use sounds for maintaining contact, especially when they are feeding or traveling in murky water. And vocalizations between mothers and calves are the most common manatee sounds. In fact, once when a mother manatee and calf were separated by a flood gate, they vocalized constantly for three hours until they were reunited.

On the whole, the sensory systems of manatees have not been well studied. So we still have more to learn about them. But it’s clear that when it comes to manatees, there’s more than what meets the eye.

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