9. A cat’s ear temperature can help you tell if he is stressed out. Cats’ responses to fear and stress include increased adrenaline and other physiological changes that lead to energy generation in the body. Part of that energy is released as heat, increasing a cat’s body temperature in several areas. Scientists have found that the temperature of a cat’s right ear (but not the left ear) is related to the level of certain hormones released in response to stress, and could be a reliable indicator of psychological stress.