Isidore of Seville [7th century CE] (Etymologies, Book 12, 6:9): boca [sea-cows] are said to be marine cows [bos[, as if the word were boacas. - [Barney, Lewis, et. al. translation]

Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Marine monsters 6.23, 6.54): [Thomas describes the sea-cow under the names focha bos marinus and vacca maris.] [Marine monsters 6.23] The sea-cow (focha bos marinus), as the Experimentator says, is the strongest animal of its kind. It does not easily change its place, but always remains where nature has placed it. It is a spirited and passionate animal, and yet not to other animals, but to its household. Aristotle: For he always fights with his wife, until he kills her; but he casts the slain one from the place, and brings over another. And so he does not cease to seduce females, until it happens that he is driven away by his own death, or is overtaken by his wife in the meantime. By the imitation of this destruction, the children live by robbery [?]. Focha, as the Liber Kyrannidarum says, has the hands of a man and the face of a calf. [Marine monsters 6.54] A sea-cow, as Aristotle says, is a monster great and strong, and furious when injured. This animal does not lay eggs, but produces a fetus; but at most it makes two, and often one. And it grows into its fullness in ten years. But the mother feeds her young for a long time and takes it with her wherever she goes, because she loves to hold it. And it should be noted that the mother is pregnant for ten months. This animal lives a hundred and thirty years; and this was proved by cutting off their tails. - [Badke translation/paraphrase]