EVERYDAY SCIENCE

Detailed explanation-1: -Birds are warm-blooded animals and are more active. Some of them often fly continuously for hours. So their energy requirement is more.

Detailed explanation-2: -An obvious explanation may be that organ sizes between similarly-sized birds and mammals may be disproportionally larger in birds compared with mammals, leading to higher BMR. Secondly, birds showed significantly lower basal cellular oxygen consumption, lipid oxidative damage, and lower activities of catalase.

Detailed explanation-3: -Scientists think that aestivation evolved so animals could cope with challenges like limited food and water supplies. During aestivation, an animal dramatically decreases its metabolic rate for many months to conserve energy-this depression in metabolic rates may be the only way to stay alive.

Detailed explanation-4: -Birds have to incubate eggs outside their body, requiring additional heat.

Detailed explanation-5: -In reality, reptiles are ectothermic animals, which means their metabolism does not generate enough heat byproducts to maintain body temperature above air or surface temperatures.