Sea cow is also called manatee.Manatees are aquatic1 mammals2 that belong to a group of animals called Sirenia3.In this group there are also dugongs.Dugongs and manatees are similar in size,colour and shape,but they're different in their tails4.Manatees have a big,rounded tail,but dugongs have flat tails,like whales'tails.海牛也叫manatee,是一种水生哺乳动物,属海牛目。海牛目的动物也包括儒艮。儒艮和海牛在大小、颜色和形状上都很相似,但它们的尾巴略有不同。海牛的尾巴大而圆,而儒艮则有着扁平的尾巴,就像鲸鱼尾巴一样。