Reptiles, referred to as "cold blooded," must rely on external sources to maintain their body temperature. If a reptile is becoming too cool, he/she will seek an elevated area to bask. If the reptile does not warm up, he can fall into a life-threatening slowed metabolic state. Overheated reptiles may seek shade, pant, lighten their skin color and burrow into cool soil. If unable to cool themselves, thyroid gland dysfunction and/or death from overheating ensues.