An ectotherm is an organism in which body heat or insulation is not of great importance, and is even negligible at times in certain animals. These creatures rely mostly on sunlight for their bodies to get warm, but if their environment had no heat available they would just adapt to the temperature of their surrounding climate. Ectotherms are known as cold-blooded creatures due to the unimportance of body heat in their day to day life. The sudden and drastic temperature changes within an ectotherm’s body is called poikilothermy. Since animal’s body temperatures change to their surrounding temperatures, if it were to get too hot then reptiles and amphibians alike would seek shade. During very cold periods in time, some organisms have the ability to slow down or completely stop their metabolic system for a period of a day to a few years! Due to the fewer mitochondria in their cells as opposed to endotherms, cold-blooded animals tend to be more sluggish in longer activities because their ATP production is not like the endotherm’s.