With mating hormones raging, every large male, having slept and basked in friendly piles all year, suddenly feels the need to drive off all others marginally smaller than himself. Lesser individuals quickly flee while the largest ‘prime’ males stake out tiny territories within a lek system made up of various other dominant rivals awaiting the favours of breeding females.
For those of equal size and strength, to gain a space in this coveted area there is only one solution: battle. This is as much a test of strength and determination as it is of endurance, head-butting, wrestling, biting. I’ve seen battles last four or five hours straight, others rage right into the night, when iguanas normally become lethargic.
At last the loser slinks away, exhausted and humiliated but not seriously injured. Maybe next year luck will come his way.