Gila Monster Intraspecific Interactions

Gila monster - male combat
Two male Gila monsters engaged in an ancient spring combat ritual. (photo courtesy of David Conklin)

In a study of southern Utah Gila monsters it was observed that from late April through late May some shelters were occupied by as many as six Gila monsters at the same time. This was not a “den” where Gilas would congregate for hibernation, but rather they would gather in the spring from up to more than a mile away.

Male-male combat has been observed in free-ranging Gila monsters. These ritualistic bouts don’t usually result in injury, but are tests of strength and endurance. They look like wrestling matches with each combatant vying for the top position. The loser leaves the area and it is presumed that the winner of such bouts then has access to females for mating.

Common shelter use and seasonal movements that bring animals back to communal areas as well as the establishment of dominance through male-male combat are important elements of a structured Gila monster social system.