Fat Insulation: How Do Animals Keep Warm?

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Updated on Oct 18, 2013

In the chilly waters of the earth’s oceans, animals survive by using a number of different strategies. Some animals are cold-blooded, and their bodies don’t need to stay very warm. Others are warm-blooded, and their bodies need to stay warm in the ocean’s cold. Sea otters fluff up their fur and add air to it, creating an insulating blanket. Seals use blubber, a thick fatty layer that also acts like a natural sweater. In this activity, you’ll explore how fat works to keep animals warm.


How does fat keep animals warm?


  • 2 cups of shortening
  • 2 clear plastic cups
  • Two thermometers
  • Two plastic gloves
  • Ice cubes
  • Cold water
  • 2 large bowls


  1. First, fill upone cup with shortening and the other cup with water. Make sure that both the shortening and water are at room temperature when you start.
  7. Add cold water into each of the largebowls, then add ice cubes.




Blubber is an insulating layer of fat under the skin. While animals that live in chilly places can’t put on a sweater, they can eat and develop this fatty layer to help them survive.In the deep ocean, the water can get down to 54 °F, and in these super chilly conditions, a layer of fat is what keeps these animals’ internal organs from freezing. Seals and small whales have a few inches of blubber, while larger whales can have a layer up to a foot thick! Blubber is especially important to marine mammals, because cold water leads to more heat loss than cold air. An animal'sblubber is also a place where it stores energy when food is scarce.

Blubber is an insulator. An insulator is something that doesn’t easily allow heat to escape. When youplaced the thermometer into the “blubber” cup, the shortening in the center of the cup was at room temperature. The shortening around the outside of the cup prevented the heat from escaping. Water is not as good at insulating, and it freezes more quickly than fat does.
