For "lion" and "lioness" do we use "it" or we can use "he" and "she"?
It's pretty much implied that a lion is a "he," and a lioness is a "she," but the average American will also use "it" if the American is lazy and doesn't want to pay attention to detail since most animals have a male and a female in the species. Using "he," "she," or "it" in everyday speech would be fine, however. We can't always determine the gender/sex of an animal when we want to speak about it briefly then move-on to a different topic in conversation. If the conversation is a bit more detailed on the animal or animals in general, and the gender(s)/sex(es) can be determined, then it'd be more proper or fitting to use "he" or "she."