The concept of the Nagual is very different.

Depending on who you ask and how you phrase the question, you might get very different answers to this question, since there are several very different definitions for this word.

To begin let me explain this: every person, at birth, is associate with some other living thing, usually an animal. That animal (usually) is known as one's nahualli. You cannot choose it, and, unless you've taken some steps to find out what it is, you probably don't know.