Visitors often photograph the Hacienda's Black Iguanas basking atop stone walls, in trees and lumbering across the ground. The other day I came upon two in the parking lot clinched together fighting, shown at .
They were young ones, only about 2-½ feet long (75cm), but clearly old enough to fight. Note that both bear bloody spots on their backs behind their heads. When male iguanas do battle the main tactic seems to be to clamp down on the other's nape.
We've collected a great deal of information about Black Iguanas, including a 2006 account of two large males who really bloodied one another. The fight is described on our Black Iguana page under the subtitle "Two Male Black Iguanas Battle it Out" down the page at http://www.backyardnature.net/yucatan/iguana-b.htm.