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How Does Blubber Keep Animals Warm?

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Living out in the wilderness isn't always easy, especially when your home is in the Arctic. Warm-blooded animals that live in the Arctic and other cold regions have to keep their body temperature up in order to survive, but a nice, thick layer of blubber makes it easier. While blubber is a fatty tissue, that doesn't mean that just any creature could survive in the cold by gaining some weight -- it's actually much more complex than that.

Cold Water Living

Despite the elements, plenty of warm-blooded mammals live in cold environments. Whales, polar bears, sea lions, seals and walruses all have to endure freezing temperatures on a regular basis -- in fact, the Arctic air can dip down to minus 40 degrees Fahrenheit. The near-freezing water temperatures also pose a threat to any non-blubbered mammals that dare go for a swim, so if it weren't for blubber, animals like polar bears would never be able to hunt for food in the water.

What Is Blubber?

Blubber is a special layer of fatty tissue that animals living in cold environments developed over time as a way of keeping warm. Animals don't just build up blubber by eating though -- thicker and heavier than normal body fat, this is a physical characteristic that animals either develop or don't. For example, sea otters don't develop blubber, so they rely on their dense fur to stay warm.

Thick Insulation

Blubber is so effective at keeping animals warm partially because it is thick and dense -- so thick, in fact, that it can account for a substantial portion of an animal's body mass. Some aquatic mammals have a mass that is as much as 50 percent blubber, particularly those that live in the coldest regions of the Arctic. For example, a whale's layer of blubber can be as thick as 20 inches.

Restricting Bloodflow

In addition to providing insulation, blubber actually manipulates a mammal's blood vessels to help it stay warm. Blubber is more densely packed with blood vessels than a typical layer of fat, and when the temperature drops, the blubber constricts those blood vessels to reduce the blood flow in the animal. By doing that, the animal spends less energy heating its own body, ultimately keeping the animal warmer without burning through energy as quickly.