why somes species don’t have their own body heat (like reptiles) and rely on the environment’s temperature when the combustion of sugar in the blood releases energy and heat (and allows us to have our own body temperature)?

Question

why somes species don’t have their own body heat (like reptiles) and rely on the environment’s temperature when the combustion of sugar in the blood releases energy and heat (and allows us to have our own body temperature)?

In: Biology

Answer 1

Imagine leaving your front door and windows open all the time. You’d certainly save money on heating and cooling, since you wouldn’t bother running those. And you’d still have heat inside the house sometimes, like if you run the oven, or the hot water, or even the heat from human bodies. But it wouldn’t stick around.