If you've ever looked at a penguin and been like, *why? Just go North*, then you're not alone. It seems like their entire lives are miserable and freezing.

Well I'm here to pretty much agree with that, but I also wondered how they're not dead. The South Pole, for example, has an average temperature of -49C. Given that ice can be ice at about 0C, you then have to double or triple that coldness to get a good idea of that.

But penguins aren't the only ones that aren't dead down there (or up, however you want to see it). There's quite a variety of life that thrive there and it's now just down to a warm, blubbery coat. Each species has a range of brilliant survival techniques and adaptations. But hell, let's start with penguins for today.

Penguins

Penguins look like stupid bumbling balls of fluff, but everything about them is uniquely adapted. They do have the obvious thick skin and fat layers, black skin and feathers on their backs to absorb the heat and so forth, but so much more, too.

Behavioural adaptations

You may know that they huddle together to share body heat, but you may not have noticed that they also take shifts being the 'outside' penguin, the one that bears the brunt of the cold. Over time, the now frozen penguins shuffle inwards to warm up and other penguins will inevitably take their place.

But it turns out this huddling is actually a little too successful. A huddle only lasts, on average, about 50 minutes, sometimes as little as 12. Why? Because the inner penguins get too hot. Perhaps via communication, a single outside penguin decides to break it up, the huddle disperses and a hot plume of air is released. Temperatures within the huddle have been seen to reach 37.7°C / 100°F!

After they disperse, the penguins are seen eating ice to cool off. Think about that. Penguins need to eat ice to cool off. In that Antarctic. And you thought Russians were tough.

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But what about when it comes to extremities like the feet which are constantly exposed to the ice and snow? They have multiple answers to this. First and foremost, they lean back on their heals and balance on their claws to minimize exposure to the ice. You can often see them walking around on their back feet which kind of explains their weird hobbling.

Physical Adaptations

This is where things get pretty neat. You see, penguins are like us, they're homeotherms - they maintain a warm body temperature. You'd think that would be impossible, but for the most part, penguins achieve this. One way to do this is through vasoconstriction, or blood vessel narrowing. This is the same kinda thing when you have a swollen body part or a pimple or whatever and you use a bag of ice to reduce the bulge. The blood vessels get constricted nearer the skin which prevents the warmth being carried by the blood being lost to the wild outdoors.

This can go too far, obviously. That's how frostbite happens - your blood and cells freeze over. But penguins have the answer again. Using something called counter-current heat exchange, which is a particularly well-devised arrangement of arteries and vessels in their legs.

Basically, the cold veins returning cold blood from the shallow parts of the penguin's skin are huddled up around the warm arteries passing new, warm blood down to the feet. By being close up, thin and wrapped around, the cold veins get to steal some excess heat being expelled from the arterial blood.

Pretty handy image found on wordpress

This prevents the feet freezing and in fact always makes sure they are slightly above 0°C despite the super-sub temperatures.

It doesn't end here!

With all this going on you might imagine penguins somehow maintain a toasty room temperature no matter what. But this isn't the case. Some penguins, like the emperor penguin actually lose a lot of core body heat - up to 15°C. This is a deliberate effect via metabolic radiative and convective cooling. Allowing their bodies to cool down actually slows their metabolism, saving energy in the coldest times. Scientists who were looking into this took thermal imagery of penguins and found that their surface temperature was actually cooler than the surrounding air. The feathers on their heads, chests and backs were a chilly -1.84, -7.24 and -9.76°F respectively (convert that on your own, I'm getting lazy) when the surrounding air was only 0.32°F. That's a significant difference! But this paradoxically allows their feathers to gain heat via convection, though this is so far seen as negligible.

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Still not enough?

Well, those beaks aren't doing much, what can evolution do with those? As it turns out, quite a bit. By using a common air chamber in the nasal passages, they have found a way to exhale air in a way that decreases its temperature to 9°C by the time it leaves the body, meaning they reclaim a good 83.4% of the heat back into their body, as well as being able to steal more heat from the inhaled air. This accounts for about 17% of the metabolic heat production at any given time!

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There's actually a whole lot more, but I wouldn't want this post to go on forever. Here's some more adaptations for the cold in short:

• A thick layer of fat around their organs, protecting them from the cold water when they swim
• Leg muscles that are raised higher from the snowy ground
• Extra feathered legs (not like regular birds, you'll observe) and incredibly dense plumage in general
• Blood that retains heat when transporting oxygen to tissues
• 30% of bodyweight dedicated to blubbery fat

The list goes on and on in order to keep eggs and chicks warm, even their bone structures to adapt to fast growth. These adaptations are incredible, and it goes to show you that John Hammond was right when he said:

'Life will find a way'

Image Sources:

Penguin Gang
Penguin Heels
Vasoconstriction
Counter-current heat exchange
Thermal Penguin