 Dear students, in this topic we shall discuss the endotherms and ectotherms. The animals are thermally classified based on the source of their body heat into two types that is endotherms and ectotherms. Endotherms are the animals that generate their own body heat through metabolism to elevate their body temperatures. Due to this heat production, they maintain the temperatures of their bodies considerably above the cold ambient temperatures. The endotherms have low thermal conductivity due to good insulation of their bodies. Insulations are found in many types of animals. For example, presence of fur, feathers or subcutaneous fat that is fat that causes insulation. Insulation enables the endotherms to conserve heat and fight high temperature gradient between the body and environment. Dear students, endotherms are of two types 1. The homeothermic endotherms 2. The heterothermic endotherms 3. Homeothermic endotherms regulate their body temperatures within relatively narrow range. They include most of the mammals and birds. The heterothermic endotherms can maintain regions of their body above the ambient temperatures. Other specific circumstances and for short periods of time. This type of heterotherms are called regional heterothermic endotherms. These are the endotherms for some parts of the body and they do not maintain the body temperatures. That is why they are regionally endothermic. Their body temperatures are divided by two types, which is why they are called heterothermic. These examples are found in large sized fishes like sharks and tuna and many flying insects are regionally heterothermic endotherms. Dear students, now we shall discuss the significance of endothermic. Endotherms can live in those habitats that are too cold for most of the ectotherms who do not produce their own heat. The animals that produce their own heat can live in a cold environment. In other climates, these animals maintain their body temperatures through metabolic heat production. Dear students, now we shall discuss ectotherms. They produce metabolic heat at low rates. To warm up their bodies, they rely on environmental sources of heat. Their bodies are poorly insulated. Heat conservation does not have structural mechanisms for the body. So they have high thermal conductance. High thermal conductance has an effect that the heat produced by their metabolic processes also quickly loses in the cooler environment. These types of animals, ectotherms, regulate their body temperatures by behavioral means. High thermal conductance does not have heat conservation. This is why they absorb heat very easily when they are in need of heat. And if they have heat production or heat absorbance, they lose easily in the environment. In colder environments, these animals behave in manners which facilitate heat absorption. While in hotter environments, they tend to dissipate heat and also minimize heat uptake from the environment. Dear students, we shall take a few examples of behavioral patterns of temperature regulation in ectotherms. 1. In cold environments, basking in the sun to gain heat observed in most of the reptiles like lizards and snakes. In hotter environments, such animals raise their bodies to avoid hot surfaces because heat will conduct from the hot surface and the temperature of the body will rise. Then the most effective means of thermal regulation in such animals is to move into some suitable micro-climates. In an environment, the animals can be hotter or colder, but there are some parts that give protection from extreme environmental situations, e.g. in the sun, that is a micro-climate. So keep hiding in burrows with moderate temperature during the day is a behavioral pattern that involves movement into a suitable temperature.