Heat Loss by Radiation OccursWhen Infrared Radiation Emitted by the Body Is Absorbed by Cooler Objects

All solid objects emit invisible electromagnetic radiation in the infrared range. Warm objects emit on a shorter wavelength and emit more emissions per unit time than do cool objects. When these emissions strike another object, some are absorbed and thus transfer heat. Although all objects emit radiant heat, the net heat transfer is from warm to cool objects. It is important to realize that radiant heat loss can occur even when a ther­mally neutral or warm environment surrounds the animal. Heat can be lost from an animal to the uninsulated walls of a building even though the intervening air is warm.