A creature known as a "cold-blooded animal" or an ectotherm (derived from the Greek meaning "outside" is one in which the internal physiological sources of heat are either minimal or of very little significance when it comes to regulating body temperature. These creatures, like frogs, depend on external heat sources to function at extremely economical metabolic rates. Homeothermic ectotherms are those that inhabit settings with nearly constant temperatures, such as those found in parts of the deep ocean. Conversely, in regions where temperature fluctuations are significant enough to restrict the physiological functions of other ectotherms, numerous species have developed a habit of searching for outside heat sources or refuge from it. For instance, numerous reptiles use a variety of behavioral thermoregulation strategies to maintain their body temperature, including tanning in the sun and seeking cover when needed. Some ectotherms can effectively regulate their body temperature through a variety of behavioral patterns. In order to maximize their exposure to the sun, reptiles and many other insects look for sunny spots to warm up. When the temperature is too high, they seek out cooler water or shade. Honey bees bundle themselves to stay warm throughout the winter. In order to accumulate heat before taking flight, moths and butterflies may arrange their wings to receive the most amount of sunlight possible.In Large group basking is beneficial for thermoregulation in gregarious caterpillars, like the fall webworm and the forest tent caterpillar. Many flying insects, like bumblebees and honey bees, vibrate their flight muscles without violently moving their wings in order to elevate their internal temperatures endothermally before taking flight. The challenge of consistently applying concepts like poikilothermy and homeothermy is demonstrated by such endothermal activity. Ectotherms are helped to regulate their body temperature by both physiological and behavioral adjustments. Reusing and thereby preserving part of the heat that would have otherwise been wasted, diving reptiles use heat exchange processes, in which cold blood from the skin absorbs heat from blood traveling outward from the body core. In order to allow for more evaporative cooling, bullfrogs' skin secretes more mucus in the heat. Entering a state of torpor causes some ectotherms to slow down or cease their metabolism completely, as in the case of the wood frog. Depending upon the species and conditions, the torpor may endure for a single night, a season, or even several years.