Subject: Re: manatee name origin

Nancy Sadusky (education@savethemanatee.org)
Mon, 28 Sep 1998 23:36:05 +0000

Dear Ali,

Thanks for your e-mail.  Here's the answers to your questions:

Q.  How did the manatees get their name? And 
what does their name mean?

A.  The name manatee comes from the Haitian word "manati." The 
scientific genus name Trichechus is Latin for hair.  "Sea cow" is 
also a common term for manatees and dugongs. This name likely comes 
from the fact that manatees are herbivores (plant-eaters), as are 
cows. 

Q. When were manatees discovered? Was it many thousands of years ago, 
or not too long ago?

A. Actual manatee fossils found all over the world go back as far as 
60 million years. Researchers believe that modern manatees evolved 
from four-footed land mammals. Manatee fossils found in Florida's 
springs date back about 45 million years. Supposedly, Christopher 
Columbus saw manatees in 1493, and William Bartram described manatees 
and manatee hunting in Florida in 1774.

Q.  How do manatees communicate?

A.   On the whole, the sensory systems of the manatee have not been 
well studied. Anatomically, manatees have extremely large
ear bones and may have a good sense of hearing. Manatees emit sounds
underwater that are used in communicating with one another. It is not
believed they are used for navigational purposes. Vocalizations may
express fear, anger, or sexual arousal. They are also used to maintain
contact, especially when manatees are feeding or traveling in turbid
water. Especially common are vocalizations between a female and calf. 

Manatee sounds can be described as chirps, whistles or squeaks, have
peak energies in the 3-5 kilohertz range, and are probably produced in
the larynx. It has been suggested, but not confirmed, that the most
sensitive location on the manatee's head for sound reception is not
the tiny ear openings located several centimeters behind the eyes, but
the area near the cheek bones, which are large and seem to be quite
oily compared with other bones in the skull and which are in direct
contact with the ear bones. This arrangement is similar to that of
dolphins. 

In addition, anatomical studies suggest that manatees are adapted to
hear infrasound, frequencies too low to be heard by the human ear,
generally less than 20 hertz. 

I hope this answers your questions.

Sincerely,
Nancy Sadusky

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