[sahy-ree-nee-uh
n] 
| an aquatic, herbivorous mammal of the order Sirenia, including the manatee and dugong. |
| sea cow n. Any of several large, cylindrical, herbivorous marine mammals of the order Sirenia, having a paddlelike tail and rounded front flippers, including the manatee, dugong, and the very large species Hydrodamalis stelleri of the northern Pacific that became extinct in the late 1700s. Also called sirenian. |
| si·re·ni·an (sī-rē'nē-ən) n. See sea cow. adj. Of or belonging to the order of sea cows. [From New Latin Sīrēnia, order name, from Latin Sīrēn, Siren; see siren.] |
sirenian
any of four large aquatic mammalian species now living primarily in tropical waters where food plants grow. The three species of manatee (genus Trichechus) occupy warm latitudes of the coastal Atlantic and associated rivers, and the dugong (Dugong dugon) inhabits the coastlines of the Indian and Pacific oceans. The extinct Steller's sea cow (Hydrodamalis gigas), formerly of the Bering Sea, also belonged to the dugong family, but all were killed off by humans less than 30 years after they were first scientifically described in 1741. Steller's sea cow was the largest sirenian and one of the few sirenians to occupy cold water. The term sea cow is now sometimes used to refer collectively to sirenians.
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