EVERYDAY SCIENCE

Detailed explanation-1: -Even though juvenile and adult birds are endothermic and maintain a constant, high body temperature by means of internal heat production, they begin life expressing an ectothermic phenotype.

Detailed explanation-2: -Reptiles and amphibians are ectotherms, while birds are endotherms. An ectotherm (reptile/amphibian) relies primarily on its external environment to regulate the temperature of its body. Endotherms (birds) are able to regulate their body temperatures by producing heat within the body.

Detailed explanation-3: -endotherm, so-called warm-blooded animals; that is, those that maintain a constant body temperature independent of the environment. The endotherms primarily include the birds and mammals; however, some fish are also endothermic.

Detailed explanation-4: -Birds are endothermic, and because they fly, they require large amounts of energy, necessitating a high metabolic rate. Like mammals, which are also endothermic, birds have an insulating covering that keeps heat in the body: feathers.

Detailed explanation-5: -Endotherms and ectotherms People, polar bears, penguins, and prairie dogs, like most other birds and mammals, are endotherms. Iguanas and rattlesnakes, like most other reptiles-along with most fishes, amphibians, and invertebrates-are ectotherms. Endotherms generate most of the heat they need internally.