Native to South America, the Rhea americana is the largest bird of this continent. In Brazil, they are native to the South, Southeast, Midwest, and Northeast, with the exception of the coastal strips. Birds, in general, have the ability to maintain their body temperature constant, losing to the environment the additional heat that is produced. In this attempt to maintain thermal equilibrium, animals use non-evaporative and evaporative mechanisms to exchange heat with environment. Behavioral changes are also common as strategies aiming heat loss to the environment. Behavior changes are the main adaptive responses of animals to various environmental stimuli and studies addressing the thermoregulatory behavior of the animals are essential to the improvement of management and production systems. The thermal changes probably occur through a set of behaviors that combined helped to maintain the homeothermy of birds. Research on thermoregulation and the behavior of Rhea are still scarce. In this context, this article presents an initial approach to the thermoregulation, from a behavioral perspective, of Rhea (Rhea americana) in hot climate regions.