Due to confusion with synonyms during translation, some of the animals depicted by the English words did not exist in ancient China . For example, 羊 can mean Goat , ram or sheep. Similarly, 鼠 Rat can also be translated as mouse, as there are no distinctive words for the two genera in Chinese . Further, 豬 Pig is sometimes translated to boar after its Japanese name, and 牛 plainly means Ox and Cow , and not water buffalo, 水牛. 雞 Rooster may mean Chicken . However, Rooster is the most commonly used one among all the synonyms, same for 羊, 鼠, etc.