Mayan Sign. Animal Spirit. Nahual. Nagual. Nawal. Different people use different terms and spellings to refer to the 20 day names used by the Maya civilization in their Tzolk'in calendar (not to be confused with the Long Count calendar). Your personal nahual is determined by your birth date. Enter your date of birth below and then click on the "Calculate my Nahual" button to find out more about your Mayan sign.