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)?

221 views

[ad_1]

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
[ad_2]

There’s more to body heat than producing energy.

You are right, “cold” blooded animals do produce body heat. However, they don’t retain it. There are a few reasons for this.

They don’t regulate their production of body heat. They don’t produce more when they’re cold by doing things like shivering.

They don’t constrict blood vessels to move blood away from their skin to reduce the loss of body heat to the environment.

The reason they don’t is that cold blooded came first. Warm blood animals evolved to be warm blooded instead of being cold blooded.

There are disadvantages to being warm blooded. One is that it requires a lot more food. Warm blooded animals have to eat a lot more food to maintain their body temperature. A lot of cold blooded animals can go very long periods without eating. Warm blooded animals have to be more active so that they can be, well, more active. They’re always closer to starving to death than cold blooded animals. In fact, some smaller warm blooded animals are in constant danger of starving to death if they don’t keep eating all day.

This is basically asking why some animals are more evolved/specialized than others. It’s just how we developed over time.

Cold blooded animals live in environments that they thrive in, and having to regulate their own temperature would cost way too much energy that wouldn’t be as “fit” in that environment. For example a reptile living in the desert would not benefit from being forced to ingest copious amounts of water + food to regulate their own temperature. That amount of food and water doesn’t exist in that environment, and so it would be disadvantageous to develop those traits.

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.