1 00:00:02,040 --> 00:00:07,120 Speaker 1: Welcome to brain stuff from how stuff works. Hey, brain stuff, 2 00:00:07,160 --> 00:00:10,040 Speaker 1: Lauren Vogel bomb here. How long could you stand on 3 00:00:10,119 --> 00:00:13,960 Speaker 1: Antarctic ice before your bare feet froze solid? A minute? 4 00:00:14,200 --> 00:00:17,119 Speaker 1: Maybe two? If you're an emperor penguin, you can do 5 00:00:17,160 --> 00:00:19,320 Speaker 1: it for two months, and in wind chills as low 6 00:00:19,360 --> 00:00:22,280 Speaker 1: as negative seventy five degrees fahrenheit that's about negative sixty 7 00:00:22,320 --> 00:00:26,400 Speaker 1: degrees celsius. Those naked bird feet may look positively frigid, 8 00:00:26,560 --> 00:00:29,240 Speaker 1: but their special circulation acts as a kind of anti 9 00:00:29,280 --> 00:00:31,800 Speaker 1: freeze to keep them just warm enough in environments where 10 00:00:31,800 --> 00:00:35,879 Speaker 1: we would get frost bite immediately. Penguins are adapted just 11 00:00:36,000 --> 00:00:39,559 Speaker 1: for cold temperatures. They have specialized super insulating feathers that 12 00:00:39,680 --> 00:00:42,680 Speaker 1: keep heat in. We humans would get frost bite in 13 00:00:42,720 --> 00:00:45,479 Speaker 1: penguins place, specifically because our bodies are adapted to a 14 00:00:45,479 --> 00:00:48,720 Speaker 1: wider range of temperatures. To keep our internal body temperature 15 00:00:48,840 --> 00:00:50,879 Speaker 1: right around in ninety eight degrees. In the heat and 16 00:00:50,960 --> 00:00:54,160 Speaker 1: the cold, the blood vessels inner skin expand or contract 17 00:00:54,360 --> 00:00:56,920 Speaker 1: to direct or restrict the flow of blood out to 18 00:00:56,920 --> 00:01:00,520 Speaker 1: our skin. Our organs stopped working. Some were above a 19 00:01:00,560 --> 00:01:03,880 Speaker 1: hundred and four degrees fahrenheit that's about forty degrees celsius. 20 00:01:03,920 --> 00:01:06,440 Speaker 1: So when we get warm, our blood vessels dilate to 21 00:01:06,520 --> 00:01:09,520 Speaker 1: circulate more warm blood to the skin, where hopefully that 22 00:01:09,600 --> 00:01:12,720 Speaker 1: heat transfers out into the environment. A sweating can help 23 00:01:12,720 --> 00:01:16,399 Speaker 1: with this, but our organs also stop working somewhere below 24 00:01:16,640 --> 00:01:20,000 Speaker 1: ninety degrees fahrenheit that's about thirty two degrees celsius. So 25 00:01:20,120 --> 00:01:22,640 Speaker 1: when we get cold, most of our blood vessels constrict 26 00:01:22,680 --> 00:01:24,679 Speaker 1: to limit the amount of warm blood going too the 27 00:01:24,680 --> 00:01:27,320 Speaker 1: skin where it would lose more heat, and thus keep 28 00:01:27,319 --> 00:01:31,000 Speaker 1: that warmth circulating in our core areas. Our hands, feet, 29 00:01:31,000 --> 00:01:33,399 Speaker 1: and limbs in particular are full of these tiny blood 30 00:01:33,480 --> 00:01:36,360 Speaker 1: vessels that can either warm up or chill off fast. 31 00:01:37,000 --> 00:01:39,880 Speaker 1: Your hands may even appear paler during exposure to freezing 32 00:01:39,920 --> 00:01:42,960 Speaker 1: weather because there's less blood in them. It's been redirected 33 00:01:42,959 --> 00:01:44,479 Speaker 1: to the core of your body to make sure those 34 00:01:44,560 --> 00:01:48,280 Speaker 1: vital organs stay warm. But penguin legs and feet have 35 00:01:48,320 --> 00:01:52,160 Speaker 1: evolved specifically to lose as little heat as possible. Penguin 36 00:01:52,200 --> 00:01:54,920 Speaker 1: feet hold onto heat by restricting blood flow in really 37 00:01:54,960 --> 00:01:59,080 Speaker 1: cold weather, keeping foot temperature just above freezing. Penguin legs 38 00:01:59,120 --> 00:02:01,840 Speaker 1: work like a heat ex change system. Blood vessels to 39 00:02:01,920 --> 00:02:04,720 Speaker 1: and from the feet are very narrow and woven closely together, 40 00:02:05,120 --> 00:02:06,880 Speaker 1: cooling the blood from the body on the way to 41 00:02:07,000 --> 00:02:09,040 Speaker 1: the feet and heating the blood as it returns to 42 00:02:09,080 --> 00:02:12,160 Speaker 1: the body. Feet get cool blood, so there's less heat 43 00:02:12,200 --> 00:02:16,400 Speaker 1: to lose while the body stays toasty. This special ability 44 00:02:16,480 --> 00:02:18,600 Speaker 1: is part of how penguins keep their eggs warm until 45 00:02:18,639 --> 00:02:22,080 Speaker 1: they hatch. Male emperor penguins incubate a single egg on 46 00:02:22,120 --> 00:02:24,280 Speaker 1: top of their feet for two months in the dark 47 00:02:24,320 --> 00:02:27,600 Speaker 1: of winter while females are out feeding at sea. They 48 00:02:27,639 --> 00:02:29,600 Speaker 1: also cover the egg with a flap of warm belly 49 00:02:29,639 --> 00:02:31,639 Speaker 1: skin called a brood pouch to keep it out of 50 00:02:31,680 --> 00:02:35,959 Speaker 1: the elements, and nurturing doesn't stop there for these dedicated dads. 51 00:02:36,240 --> 00:02:38,280 Speaker 1: If females haven't returned with food by the time the 52 00:02:38,320 --> 00:02:40,960 Speaker 1: chicks hatch, male emperors feed their babies for a few 53 00:02:41,000 --> 00:02:43,600 Speaker 1: days on a kind of milk made from special cells 54 00:02:43,639 --> 00:02:51,639 Speaker 1: inside their throats. Today's episode was written by Lori and 55 00:02:51,720 --> 00:02:54,160 Speaker 1: Fick and produced by Tyler Clang for iHeart Media and 56 00:02:54,160 --> 00:02:56,480 Speaker 1: How Stuff Works. To learn more about this and lots 57 00:02:56,520 --> 00:02:59,160 Speaker 1: of other core topics, visit our home planet, how stuff 58 00:02:59,200 --> 00:03:11,240 Speaker 1: Works dot Com.