Speaker 1: Welcome to brain stuff from how stuff works. Hey, brain stuff,
Speaker 1: Lauren Vogel bomb here. How long could you stand on
Speaker 1: Antarctic ice before your bare feet froze solid? A minute?
Speaker 1: Maybe two? If you're an emperor penguin, you can do
Speaker 1: it for two months, and in wind chills as low
Speaker 1: as negative seventy five degrees fahrenheit that's about negative sixty
Speaker 1: degrees celsius. Those naked bird feet may look positively frigid,
Speaker 1: but their special circulation acts as a kind of anti
Speaker 1: freeze to keep them just warm enough in environments where
Speaker 1: we would get frost bite immediately. Penguins are adapted just
Speaker 1: for cold temperatures. They have specialized super insulating feathers that
Speaker 1: keep heat in. We humans would get frost bite in
Speaker 1: penguins place, specifically because our bodies are adapted to a
Speaker 1: wider range of temperatures. To keep our internal body temperature
Speaker 1: right around in ninety eight degrees. In the heat and
Speaker 1: the cold, the blood vessels inner skin expand or contract
Speaker 1: to direct or restrict the flow of blood out to
Speaker 1: our skin. Our organs stopped working. Some were above a
Speaker 1: hundred and four degrees fahrenheit that's about forty degrees celsius.
Speaker 1: So when we get warm, our blood vessels dilate to
Speaker 1: circulate more warm blood to the skin, where hopefully that
Speaker 1: heat transfers out into the environment. A sweating can help
Speaker 1: with this, but our organs also stop working somewhere below
Speaker 1: ninety degrees fahrenheit that's about thirty two degrees celsius. So
Speaker 1: when we get cold, most of our blood vessels constrict
Speaker 1: to limit the amount of warm blood going too the
Speaker 1: skin where it would lose more heat, and thus keep
Speaker 1: that warmth circulating in our core areas. Our hands, feet,
Speaker 1: and limbs in particular are full of these tiny blood
Speaker 1: vessels that can either warm up or chill off fast.
Speaker 1: Your hands may even appear paler during exposure to freezing
Speaker 1: weather because there's less blood in them. It's been redirected
Speaker 1: to the core of your body to make sure those
Speaker 1: vital organs stay warm. But penguin legs and feet have
Speaker 1: evolved specifically to lose as little heat as possible. Penguin
Speaker 1: feet hold onto heat by restricting blood flow in really
Speaker 1: cold weather, keeping foot temperature just above freezing. Penguin legs
Speaker 1: work like a heat ex change system. Blood vessels to
Speaker 1: and from the feet are very narrow and woven closely together,
Speaker 1: cooling the blood from the body on the way to
Speaker 1: the feet and heating the blood as it returns to
Speaker 1: the body. Feet get cool blood, so there's less heat
Speaker 1: to lose while the body stays toasty. This special ability
Speaker 1: is part of how penguins keep their eggs warm until
Speaker 1: they hatch. Male emperor penguins incubate a single egg on
Speaker 1: top of their feet for two months in the dark
Speaker 1: of winter while females are out feeding at sea. They
Speaker 1: also cover the egg with a flap of warm belly
Speaker 1: skin called a brood pouch to keep it out of
Speaker 1: the elements, and nurturing doesn't stop there for these dedicated dads.
Speaker 1: If females haven't returned with food by the time the
Speaker 1: chicks hatch, male emperors feed their babies for a few
Speaker 1: days on a kind of milk made from special cells
Speaker 1: inside their throats. Today's episode was written by Lori and
Speaker 1: Fick and produced by Tyler Clang for iHeart Media and
Speaker 1: How Stuff Works. To learn more about this and lots
Speaker 1: of other core topics, visit our home planet, how stuff
Speaker 1: Works dot Com.