I told you guys before, its not unheard of
Sea slugs are called sea cows in Japanese. Quite literally, the name is umiushi (海牛). Umi is sea, ushi is cow. Crocodiles are not called cows or bulls in Japanese. Their name, wani (鰐), simply means "crocodile". The wordplay connecting crocodiles to bovine does not exist in Japanese, trying to use another connection that does exist in Japanese does nothing for this theory.