When threatened, iguanas, monitors and other lizards tend to display defensive aggression. They stand sideways to the threat, swallow air to increase their size, stand high off the ground to look bigger and lash at the threat with their tails. Some lizards may display head bobbing and push-ups or gape and threaten to bite. | When threatened, iguanas, monitors and other lizards tend to display defensive aggression. They stand sideways to the threat, swallow air to increase their size, stand high off the ground to look bigger and lash at the threat with their tails. Some lizards may display head bobbing and push-ups or gape and threaten to bite. |