They rattle when they feel threatened
they are very aggressive
they are a greenish brown color
Both are a number (6) multiplied by a variable (z).
However, 6z is the correct way to write this.
We usually write the number first, that's just the way it's done.
It sort of makes sense because 6z is literally equal to 6 z's.
Not consisting of or related to language : not linguistic
… nonlinguistic sounds such as whistles, yells, laughs, and cries … —American Speech
… produce as their immediate response a linguistic or nonlinguistic signal of understanding or continued attention. —W. Nelson Francis