These shape-shifters were revered by the Aztecs and are native to the central lands of the Americas. Most reports speak of their odd flesh color that may be a result of either face paint or their tropical environment (which has caused many an explorer to change color).
The Aztecs referred to them as the Nagual people (Nagual is their jaguar counterpart).
They also worshipped Werejaguars as Tezcatlipoca, the Nagual Jaguar God.