noun
sirenian; sea cow
Zoological term for aquatic mammals of the order Sirenia, including manatees and dugongs.
カイギュウは絶滅の危機に瀕している。
Sirenians are on the verge of extinction.
マナティーはカイギュウの一種だ。
The manatee is a type of sirenian.
マナティー specifically refers to manatees, while カイギュウ is the broader scientific term for the order Sirenia.
ジュゴン is the dugong, a specific species within Sirenia; カイギュウ covers both manatees and dugongs.
Compound of 海 (sea) and 牛 (cow), calque of English 'sea cow'.