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Jessi: Oh, hey guys, we're just cooling off here reading about some cool polar animals. But have you ever wondered how animals can live in super cold places all the time? Animals like beluga whales, harp seals, emperor penguins, and polar bears. They certainly don't wear sweaters, but they're perfectly comfortable where they live.

These animals are warm blooded. That means their body stays the same temperature on the inside no matter how hot or cold it is on the outside. Humans are warm blooded, too, and so are rats. But not Squeaks. If you've ever had your temperature taken, then you know how the doctor uses a thermometer to take the temperature of your body inside. It's usually right around 37 degrees Celsius.

Well, whales that live in cold waters need to have the same internal temperatures as warm blooded animals in any other part of the world, from about 35 to 42 degrees Celsius. But the cold water means they can lose heat really fast, and whales can't snuggle up into a ball, find shelter, or put on an extra sweater like we can. So how do whales stay warm?

Blubber! And not just whales, seals and walruses have it too. Blubber is a thick layer of fat between an animal's skin and it's muscles. Whales are almost entirely covered in it, except for their fins, their flippers, and their flukes, also known as the whale's tails. And blubber is really special, it's not like the fat on humans and other animals. First of all, blubber is a lot thicker than fat. In dolphins, it can be just a few centimeters thick, but some kinds of whales known as bowhead whales can have a layer of blubber that's more than 30 cm thick. Whoa! That's a whole lot of blub!

Blubber also feels different, it's more firm and springy than other fat. Finally, blubber is different because it just serves a different purpose than other fat. For people, fat is a way to store extra energy that we get from food, but for whales and walruses, blubber is like putting on a super thick winter coat. It traps their body heat inside their bodies and keeps it from spreading out into the cold water. With their special blubbery coat, whales can stay perfectly comfortable in water that's two degrees below zero. That's below freezing!

Blubber's awesome, but what about other animals that live in cold climates that don't have blubber? What about polar bears? Polar bears have fat that's pretty similar to human fat, so it's not that useful for helping them stay warm. Instead, polar bears have two kinds of fur: a super thick inner layer and an oily outside layer called guard hair. The inner layer of fur traps their body heat as it leaves their skin, and their longer guard layer keeps the inside layer totally dry when they swim in the water. Together, these special fur layers keep the polar bear nice and warm.

But this next animal doesn't have blubber or fur. Emperor penguins have a different cool trick to stay warm. They use each other. During the coldest months in Antarctica, penguins huddle together to trap warm air between their bodies. Instead of standing alone and being totally exposed to the cold wind, the penguins squish together so they're surrounded by the body heat of other penguins. Of course, it's not so nice for the penguins on the outside of the circle, but the huddle is always moving. The cold penguins on the outside get to move to the center, while the warm penguins in the middle move out to take their turn on the edge. Way to share, penguins!

Animals have some pretty cool ways to deal with the cold, but since I don't have blubber, thick fur, or other penguins to snuggle with, I'm thankful for the fort, my sweaters, and my blankets. What are you thankful for? If you'd like to let us know or if you have a question, you can leave a comment below or email us at kids@thescishow.com. See you later.

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