"A mouse is an animal."
Translation:עכבר זה חיה.
What role does זה play here? Because I would have assumed, based on what I know of the "to be" verb in Hebrew, that עכבר חיה would have been sufficient: A mouse [is] an animal.
Since both עכבר and חיה are nouns you must use one of the words "זה" or "הוא" as a "verb-like" word (It is called "Copula", in Hebrew אוגד).
Can we use both זה and הוא here? Do they have any difference in such sentences?
I would think the use of זֶה makes it more of a definition, like "Can you define, what a mouse is? Yes, a mouse, that is an animal". On the other hand הוּא is a simple statement, like a mouse is brown or a mouse has whiskers, whiskers and brownness do not define a mouse.