0:00:02 > 0:00:03'Animals are amazing.'
0:00:03 > 0:00:05That's astonishing.
0:00:05 > 0:00:09'And the more we find out about them, the more amazing they seem.'
0:00:09 > 0:00:11That feels pretty harsh.
0:00:11 > 0:00:15'That's why scientists all over the world are trying their best
0:00:15 > 0:00:16'to copy them.'
0:00:16 > 0:00:18This is in the future.
0:00:18 > 0:00:20'Making brand new inventions...' Tomato juice.
0:00:20 > 0:00:22'..based on what animals can do.
0:00:22 > 0:00:25'Some are astounding...'
0:00:25 > 0:00:27We've just dived under the sea.
0:00:27 > 0:00:29'..some bizarre....'
0:00:29 > 0:00:30This is not at all pleasant.
0:00:32 > 0:00:34Yes, it's gone!
0:00:34 > 0:00:38'..but they're all inspired by the miracles of nature.
0:00:40 > 0:00:42'Episode 8.
0:00:44 > 0:00:48'How a husky can help us... keep our cool.
0:00:57 > 0:01:00'In searing conditions like these,
0:01:00 > 0:01:05'there comes a point when the human body can actually stop sweating.
0:01:09 > 0:01:11'Which is a worry.
0:01:16 > 0:01:18'Because if you can't sweat,
0:01:18 > 0:01:22'you lose the ability to regulate your own temperature.
0:01:23 > 0:01:27'And going more than just a few degrees above normal
0:01:27 > 0:01:29'will start to affect your brain.
0:01:33 > 0:01:35'Until you lose the power
0:01:35 > 0:01:38'to do even the simplest of things.'
0:01:40 > 0:01:43As I shall now demonstrate using this child's toy.
0:01:43 > 0:01:46Obviously, for this to be rigorously scientific,
0:01:46 > 0:01:48I should first have demonstrated to you
0:01:48 > 0:01:52how good I am in my front room at room temperature.
0:01:52 > 0:01:55I'm brilliant at it, that's all you need to know.
0:01:55 > 0:01:58I'll now try it on a blazing hot salt pan.
0:01:58 > 0:02:00Right, here we go.
0:02:00 > 0:02:02- TOY:- Bop it!
0:02:02 > 0:02:05'The idea is that I just copy what the toy tells me to do.'
0:02:15 > 0:02:17Twist it!
0:02:17 > 0:02:18Twist it!
0:02:18 > 0:02:19'But I seem incapable
0:02:19 > 0:02:23'of following more than three or four instructions.'
0:02:23 > 0:02:26'Which even by my standards is bad.'
0:02:26 > 0:02:29What actually is happening is as your brain gets hot,
0:02:29 > 0:02:31it lets you down in three critical areas.
0:02:31 > 0:02:33First of all...
0:02:33 > 0:02:35I've forgotten!
0:02:37 > 0:02:40What actually happens, as your brain gets hot,
0:02:40 > 0:02:42it lets you down in three critical areas.
0:02:42 > 0:02:43First of all, working memory.
0:02:43 > 0:02:46That's, in this case, remembering which of these things does what.
0:02:46 > 0:02:48Then your short-term memory,
0:02:48 > 0:02:50remembering what the machine's told you to do.
0:02:50 > 0:02:51And finally, co-ordination.
0:02:51 > 0:02:54You might remember what it's told you to do and which one does it,
0:02:54 > 0:02:57but you've got to get your hand there and use it.
0:02:57 > 0:03:00Which is why, ridiculous though it might look, for our purposes,
0:03:00 > 0:03:04this was actually quite a good test of those three things at speed.
0:03:04 > 0:03:06Do some more.
0:03:06 > 0:03:07Twist it!
0:03:07 > 0:03:09No!
0:03:10 > 0:03:12Stupid toy, anyway.
0:03:13 > 0:03:18'Luckily, the natural world has a way to keep our brains cool.'
0:03:18 > 0:03:21It's just that it's not found in the desert.
0:03:22 > 0:03:25It's in the frozen north.
0:03:27 > 0:03:29An animal that can survive
0:03:29 > 0:03:32some of the coldest temperatures on the planet.
0:03:34 > 0:03:36That animal is the husky.
0:03:43 > 0:03:49Huskies have evolved to live in unimaginably cold conditions.
0:03:49 > 0:03:53And not just to work and play, also to sleep on the ice
0:03:53 > 0:03:57at minus whatever, and they do that, cos, yeah, they have a fur coat,
0:03:57 > 0:04:00but it's not just a single fur coat, they're wearing two.
0:04:00 > 0:04:03There's the outer layer of coarse, waterproof hairs,
0:04:03 > 0:04:05and on the inside, underneath,
0:04:05 > 0:04:09there's a second layer of this soft, insulating fur.
0:04:09 > 0:04:11And it works really, really well.
0:04:11 > 0:04:15The problem is, what about when they exert themselves?
0:04:15 > 0:04:16DOGS BARK
0:04:16 > 0:04:19Huskies are bred to be sled dogs.
0:04:19 > 0:04:22They're capable of covering 100 miles in a single day.
0:04:24 > 0:04:27So how do they cope with getting hot?
0:04:28 > 0:04:32Right, if everybody's ready, 15 seconds to start.
0:04:33 > 0:04:36In 10...
0:04:36 > 0:04:37nine...
0:04:37 > 0:04:38eight...seven...
0:04:38 > 0:04:40six...five...
0:04:40 > 0:04:41four...
0:04:41 > 0:04:42three...
0:04:42 > 0:04:43two...one...
0:04:43 > 0:04:45Go!
0:04:45 > 0:04:46Ha-ha!
0:04:49 > 0:04:52You might think that heat isn't really a problem
0:04:52 > 0:04:54in Arctic conditions.
0:04:54 > 0:04:58So to make their super-power a bit more obvious,
0:04:58 > 0:05:03we've decided to race them somewhere just that little bit hotter.
0:05:08 > 0:05:10Without the cold snow,
0:05:10 > 0:05:14the huskies' temperature control is even more important.
0:05:16 > 0:05:20Especially as they're incapable of sweating through those thick coats.
0:05:31 > 0:05:35But they're still managing to lower their core temperature
0:05:35 > 0:05:38by using their paws.
0:05:47 > 0:05:48And there you go.
0:05:48 > 0:05:50That's a win for the blue team,
0:05:50 > 0:05:53and that's how important managing that body temperature is.
0:05:53 > 0:05:56So let me try and get a closer look at those paws.
0:05:56 > 0:05:57If I can.
0:05:59 > 0:06:02With this special heat-sensitive camera,
0:06:02 > 0:06:04I'll try and show you what I mean.
0:06:05 > 0:06:09You can see that this dog is a fairly even temperature,
0:06:09 > 0:06:12but its paws are glowing white-hot.
0:06:13 > 0:06:16They're criss-crossed by a network of tiny blood vessels,
0:06:16 > 0:06:20which means these pads basically work like amazing little radiators,
0:06:20 > 0:06:23letting out heat and cooling the blood
0:06:23 > 0:06:27before it's pumped back to the husky's body and brain.
0:06:27 > 0:06:32And it's that miracle of natural design that's led to an invention
0:06:32 > 0:06:35that might just help us keep our cool.
0:06:37 > 0:06:41To prove it, we're going to put these ten men
0:06:41 > 0:06:44to the same sort of test as the huskies.
0:06:47 > 0:06:50Like the dogs, their bodies and heads are covered,
0:06:50 > 0:06:53making it difficult for them to sweat out excess heat.
0:06:54 > 0:06:59And we're making it just that little bit warmer than they're used to.
0:07:01 > 0:07:03So, let's get cracking.
0:07:13 > 0:07:17As they get stuck in, we keep cranking up the heat.
0:07:18 > 0:07:21Until, like me on the saltpan,
0:07:21 > 0:07:24we see them start to make silly mistakes.
0:07:28 > 0:07:31It's at that point that we remove two of the men
0:07:31 > 0:07:35to take part in a little experiment...using this.
0:07:39 > 0:07:43This odd-looking cylinder is designed to cool us down quick.
0:07:43 > 0:07:45Like a husky's paws,
0:07:45 > 0:07:49our hands are filled with lots of tiny blood vessels,
0:07:49 > 0:07:52but they're much deeper under the skin.
0:07:52 > 0:07:56This device creates a vacuum to bring them closer to the surface,
0:07:56 > 0:08:02where a chilled cone of metal quickly cools down the hot blood.
0:08:02 > 0:08:06These gauges represent each man's core temperature.
0:08:08 > 0:08:12And you can plainly see the effect of the glove.
0:08:15 > 0:08:17More to the point, they can feel it.
0:08:19 > 0:08:23Just two minutes of cooling is enough to get our first guinea pig
0:08:23 > 0:08:25ready for action again...
0:08:26 > 0:08:28..long before his team-mate has recovered.
0:08:31 > 0:08:34It's time I tried this thing for myself.
0:08:34 > 0:08:35So here goes.
0:08:36 > 0:08:39That's a good seal to enable the vacuum.
0:08:39 > 0:08:41The vacuum is important, remember,
0:08:41 > 0:08:44it's pulling my capillaries in my hand to the surface.
0:08:44 > 0:08:49They're then closer to contact with the cooling iced water,
0:08:49 > 0:08:51and the idea of this isn't to cool my hand,
0:08:51 > 0:08:52which does feel cool right now,
0:08:52 > 0:08:55it's cooling the blood in those capillaries closer to the surface,
0:08:55 > 0:08:58which is returning through my body, lowering my core,
0:08:58 > 0:09:01and more to the point, lowering the temperature in my brain.
0:09:01 > 0:09:04The quickest way to cool this right now is to cool that.
0:09:04 > 0:09:06Right, the acid test.
0:09:08 > 0:09:10I feel sharper and cooler already.
0:09:12 > 0:09:14- TOY:- Flick it!
0:09:14 > 0:09:16Pull it!
0:09:16 > 0:09:18Pull it!
0:09:18 > 0:09:20Bop it!
0:09:20 > 0:09:21Tweak it!
0:09:21 > 0:09:23Twist it!
0:09:23 > 0:09:24Pull it!
0:09:27 > 0:09:32And so there you have it - one of the very cool miracles of nature.