They do so by converting some of the food they eat into fat. Humans store energy in the form of fat, too. But we also have a small amount of brown fat, which burns calories to keep us warm.

Animals store fat for two main reasons: to survive periods without food and to help them get through cold weather.

There are three types of fat — white, brown and adipose tissue (AT). AT is what we humans and other mammals have, while fish have a different kind called yellow fat.

White Fat

White fat stores energy in the form of lipids (fats). It helps keep an animal’s internal temperature steady and protects organs from injury or damage. It cushions joints, insulates nerves and stores vitamins A and D. If you’ve ever seen pictures of obese people with huge bellies, that’s where all their excess white fat is stored!

Brown Fat

Brown fat is found mostly in newborns and hibernating mammals such as squirrels and bears; it helps keep them warm by burning calories through non-shivering thermogenesis (internal heat generation). This type of fat was named for its rich brown color when viewed under a microscope.

Last modified: August 3, 2022