0:00:02 > 0:00:05Australia! Home of the possum, cool surfer dudes, strange lingo,
0:00:05 > 0:00:08fair dinkum, lots of sunshine and the bonzer Barrier Reef!
0:00:08 > 0:00:11It's the biggest, most spectacular coral reef in the world.
0:00:11 > 0:00:14And what's more, every creature is linked to another.
0:00:14 > 0:00:18Just imagine one huge family tree dating back 18 million years.
0:00:18 > 0:00:22From the minuscule, to the mammoth, to the miraculous,
0:00:22 > 0:00:24they're all connected in Barney's Barrier Reef!
0:00:45 > 0:00:48- What are we wearing, Barney? - If you want to go swimming
0:00:48 > 0:00:50with the fishes and breathe underwater,
0:00:50 > 0:00:53- you've got to wear this gear. - I feel so clumsy in it, though!
0:00:53 > 0:00:55I know, I need to lie down!
0:00:55 > 0:00:57you don't see any of the fish out in the ocean
0:00:57 > 0:01:00wearing all this stuff to breathe underwater.
0:01:00 > 0:01:02How do they manage it and look so cool, calm and collected?
0:01:02 > 0:01:05They have their own methods of breathing underwater.
0:01:05 > 0:01:06And they make it look cooler.
0:01:06 > 0:01:09Do you know what? It almost takes my breath away.
0:01:15 > 0:01:18Fish breathe water like we breathe air.
0:01:18 > 0:01:21I guess that makes sense, but how?
0:01:21 > 0:01:24Through their gills, these little frilly things here.
0:01:24 > 0:01:25They breathe in through their mouth
0:01:25 > 0:01:28and out through their gills into the water.
0:01:28 > 0:01:31It's like us breathing through our mouths and out of our ears!
0:01:31 > 0:01:35But I don't get it! Don't they need oxygen to survive, like us?
0:01:35 > 0:01:36What do you reckon, Dr Barnacle?
0:01:36 > 0:01:38Ah-ha, that's correct, Gemma,
0:01:38 > 0:01:41but they breathe in water from which they take in the oxygen.
0:01:41 > 0:01:43You see, the oxygen is in the water.
0:01:43 > 0:01:45And that flap of skin inside the mouth
0:01:45 > 0:01:47helps stop the water going back out again.
0:01:47 > 0:01:51If I didn't know better, I'd say that funny looking potato cod
0:01:51 > 0:01:54was talking to himself, but he's just breathing then, yeah?
0:01:54 > 0:01:56And, my, what big lips he has!
0:01:58 > 0:02:01Next, please!
0:02:02 > 0:02:05Our friend here, the moray eel, is an extreme example
0:02:05 > 0:02:08of how fish breathe in the underwater world.
0:02:08 > 0:02:11- He does look ridiculous!- All that opening and closing
0:02:11 > 0:02:13is one of the reasons people think he's fierce,
0:02:13 > 0:02:15but all he's doing is breathing.
0:02:15 > 0:02:19Many eels have this habit of looking like they're chattering away,
0:02:19 > 0:02:22but they have to use their mouth overtime to pump water
0:02:22 > 0:02:25over their gills, which are on the back of the head, just there.
0:02:25 > 0:02:29Oh, I don't get it! So, why don't all fish gulp like that, then?
0:02:29 > 0:02:32Because the eels aren't swimming - water doesn't flow
0:02:32 > 0:02:36as easily through their mouth and over their gills when they're still.
0:02:36 > 0:02:38This is why they look like they're either bad tempered,
0:02:38 > 0:02:40or talking themselves into a corner.
0:02:40 > 0:02:43So, eels are connected to our potato cod
0:02:43 > 0:02:45because they both breathe
0:02:45 > 0:02:47through their mouths and gills.
0:02:47 > 0:02:52From the overly chatty eels, to the elegant and sweeping manta rays.
0:02:52 > 0:02:53Wow, look at them go!
0:02:53 > 0:02:57You'd never know they were related to sharks, would you?
0:02:57 > 0:03:00No, not much family resemblance at all, but sharks and mantas
0:03:00 > 0:03:03do share an ability to move and swim with ease,
0:03:03 > 0:03:07and that's helped by the fact that they both have
0:03:07 > 0:03:11not two, not four, not even eight, but ten gills each!
0:03:11 > 0:03:14What? That's amazing. Most fishing creatures like eels only have two!
0:03:14 > 0:03:16They're so much bigger than an eel,
0:03:16 > 0:03:20they need bigger gills to breathe because they need more oxygen.
0:03:20 > 0:03:24It's like bigger people having bigger lungs. Bigger fish need bigger gills.
0:03:24 > 0:03:26So, like our mad moray eel and mates,
0:03:26 > 0:03:29the mantas have to push water over their gills to breathe,
0:03:29 > 0:03:31even if the eels have been a little
0:03:31 > 0:03:33short-changed on the gill front.
0:03:33 > 0:03:36So, they're connected by gills.
0:03:36 > 0:03:39So, I said I wanted blue stripes with a hint of yellow,
0:03:39 > 0:03:42- but I think it's far too much yellow.- Ooh! I never!
0:03:42 > 0:03:45These two may look like they're having a good old chinwag,
0:03:45 > 0:03:47but they're actually just having a good nosh up
0:03:47 > 0:03:51with their pincers and legs. These are squat lobsters.
0:03:51 > 0:03:53Aah! They're diddy lobsters!
0:03:53 > 0:03:55Actually, they're called squat lobsters,
0:03:55 > 0:03:57but...they're not a lobster.
0:03:57 > 0:03:59What?
0:03:59 > 0:04:02They look like lobsters, they're called lobsters,
0:04:02 > 0:04:05- but they're not lobsters? - They're crustaceans.
0:04:05 > 0:04:06That's the same thing.
0:04:06 > 0:04:08They're not. They're kind of like lobsters,
0:04:08 > 0:04:11but they're more closely related to crabs.
0:04:11 > 0:04:13But back to the matter in hand - breathing.
0:04:13 > 0:04:16Where are their gills - those bits around their mouth?
0:04:16 > 0:04:18You'd think so, wouldn't you, Barnaby?
0:04:18 > 0:04:21No, those are actually just their mouth parts.
0:04:21 > 0:04:23While they're twitching these bits,
0:04:23 > 0:04:27it helps to push water over their gills right inside this little shell.
0:04:27 > 0:04:28The manta ray has ten sets of gills
0:04:28 > 0:04:31and the lobster has gills inside its shell?
0:04:31 > 0:04:32Yes, and they both push water
0:04:32 > 0:04:34over them to breathe.
0:04:34 > 0:04:35That's our connection!
0:04:37 > 0:04:41- Barney, meet the barnacle! - Oh, hi there, barnacle!
0:04:41 > 0:04:42Hello!
0:04:42 > 0:04:46Barnacles are arthropods, related to crabs, shrimps and lobsters.
0:04:46 > 0:04:49OK, well, I can't see the family resemblance myself.
0:04:49 > 0:04:52Well, unlike their spindly relatives,
0:04:52 > 0:04:54barnacles are usually fixed to one spot forever.
0:04:54 > 0:04:57So he has to wave all day? Well, at least he's friendly!
0:04:57 > 0:05:00Duh! He's not waving, he's breathing!
0:05:00 > 0:05:03Since when does shaking a feather duster in the air
0:05:03 > 0:05:05- count as breathing? - Those are his legs!
0:05:05 > 0:05:09He opens the hole in his crater and dangles out his legs,
0:05:09 > 0:05:13then uses his hairy feet to pick up food and oxygen from the water.
0:05:13 > 0:05:15He breathes through his feet?
0:05:15 > 0:05:17- Yep!- Now, that I cannot imagine!
0:05:17 > 0:05:19Go on, son! Wave your hands in the air!
0:05:19 > 0:05:21Like you want to breathe!
0:05:21 > 0:05:22He's good!
0:05:22 > 0:05:24So, the not a lobster, squat lobster,
0:05:24 > 0:05:28waves its mouth parts around to breathe, and the Barney barnacle
0:05:28 > 0:05:31sucks in oxygen through his dancing hairy feet!
0:05:31 > 0:05:33OK, so they both dance to breathe,
0:05:33 > 0:05:34that's the connection!
0:05:37 > 0:05:39Now, when it comes to ocean creatures,
0:05:39 > 0:05:42they have some strange ways of doing things,
0:05:42 > 0:05:44and breathing is one of them.
0:05:44 > 0:05:46So, how do we get from the potato cod
0:05:46 > 0:05:48to the little foot-breathing barnacle?
0:05:48 > 0:05:50Well, me and Gemma were having a conversation
0:05:50 > 0:05:52about how fish breathe underwater
0:05:52 > 0:05:54and that led us to Mr potato cod.
0:05:54 > 0:05:58With a mouth that big I'm surprised he needs anything else to breathe.
0:05:58 > 0:06:02It's huge! But, like most other fish, he also uses his gills.
0:06:02 > 0:06:05Which links him to our gobby moray eel and his mates.
0:06:05 > 0:06:07Now, it looks like he's having a moan underwater like this.
0:06:09 > 0:06:12He's not moaning - he's breathing water through his mouth to his gills
0:06:12 > 0:06:13so that he can breathe.
0:06:13 > 0:06:16For more supreme gill action, let's not forget
0:06:16 > 0:06:19the magnificent manta ray. He's got ten of them!
0:06:19 > 0:06:22- That's like us having ten nostrils! - That's cool!- Really?
0:06:22 > 0:06:25- Yeah, you've got to blow your nose on a massive tissue!- Eeew!
0:06:25 > 0:06:28Not as ingenious as our not a lobster, squat lobster.
0:06:28 > 0:06:30He moves his body parts to get his fair share of oxygen.
0:06:30 > 0:06:34A bit like the barmy barnacle who waves his skinny legs and feet
0:06:34 > 0:06:36in the air like you just don't care so he can breathe.
0:06:36 > 0:06:38Who's our next bonkers breather?
0:06:42 > 0:06:47OK, what has no head, no brain, no heart, no lungs, no gills,
0:06:47 > 0:06:52is 95 per cent made up of water and breathes throughout his whole body?
0:06:52 > 0:06:56That would be the watery reef fish, Gemma. Yeah, no, no, no...
0:06:56 > 0:06:58It's the no body parts fish.
0:06:58 > 0:07:00- Yeah, it's got no body parts. It's a fish...- No.
0:07:00 > 0:07:02- No.- No, you just made those up!- Yes.
0:07:02 > 0:07:06- This one actually exists - it's the jellyfish!- Oh, I love jelly!
0:07:10 > 0:07:12Jellyfish? What, really?
0:07:12 > 0:07:1495 per cent water, no lungs, no gills?
0:07:14 > 0:07:17- Are you sure?- Yep, they're spookily empty
0:07:17 > 0:07:20of anything other than tentacles and water.
0:07:20 > 0:07:23But they look like they're breathing. Look at them move!
0:07:23 > 0:07:27They're just moving through the current. That's not how they breathe.
0:07:27 > 0:07:30How do they breathe if they don't have nostrils or gills or lungs?
0:07:30 > 0:07:33They're so see-through and spongy,
0:07:33 > 0:07:35they breathe through their whole body.
0:07:35 > 0:07:37Jellyfish are all about breathing.
0:07:37 > 0:07:39They're one big breathing machine.
0:07:39 > 0:07:42Water is where all the oxygen is,
0:07:42 > 0:07:45and water goes straight through these guys.
0:07:45 > 0:07:48That's weird! That's like us being completely covered in lung.
0:07:48 > 0:07:50That's gross when you think of it that way,
0:07:50 > 0:07:51but you're kind of right.
0:07:51 > 0:07:54Both the barnacles and jellyfish have no gills,
0:07:54 > 0:07:56so they find another way of breathing.
0:07:56 > 0:07:58The barnacles through their feet,
0:07:58 > 0:08:00and the jellyfish through their whole body.
0:08:00 > 0:08:01So, they're linked because
0:08:01 > 0:08:03they're both gill-less wonders.
0:08:05 > 0:08:09Sea creatures have lots of different ways of breathing underwater.
0:08:09 > 0:08:11Some just a lot weirder than others!
0:08:11 > 0:08:13If it's weird breathing you want, Gem,
0:08:13 > 0:08:15boy, have I got the animal for you.
0:08:15 > 0:08:16It's the sea snake.
0:08:16 > 0:08:18A pretty multi-skilled creature.
0:08:18 > 0:08:23He has venom, fangs, speed, a paddle tail, nice curvy moves,
0:08:23 > 0:08:27but he also has no gills, so how do you think he breathes?
0:08:27 > 0:08:29Judging from the line-up so far, it's anyone's guess!
0:08:29 > 0:08:32I don't know, his scales? Tail, maybe?
0:08:32 > 0:08:34Well, his tail is nearer.
0:08:34 > 0:08:38The sea snake can actually breathe oxygen through his bottom.
0:08:38 > 0:08:40What? Breathing through his bum?
0:08:40 > 0:08:43He's got nostrils, so why does he need to breathe from that end?
0:08:43 > 0:08:46He can come to the surface to breathe air through his nose,
0:08:46 > 0:08:49but while he's underwater, he can breathe through his bum
0:08:49 > 0:08:52because that's the only area where his skin is thin enough
0:08:52 > 0:08:54to allow the oxygen through.
0:08:54 > 0:08:57Bottom breathing is like a back-up to give them a little help
0:08:57 > 0:08:58when they're underwater.
0:08:58 > 0:09:01If he breathed through his nostrils underwater,
0:09:01 > 0:09:03he'd have a mouth full of water, like us.
0:09:03 > 0:09:06But he's diving so deep! How does he manage to stay under?
0:09:06 > 0:09:08He takes a mammoth breath and dives.
0:09:08 > 0:09:11He can stay under water for up to two hours.
0:09:11 > 0:09:14- Come on, shall we give it a try?- Go on!- Ready, big breath!
0:09:23 > 0:09:25I reckon about 45 seconds.
0:09:25 > 0:09:26I counted 50!
0:09:27 > 0:09:31So, that means that, roughly, the sea snake can hold their breath
0:09:31 > 0:09:32200 times longer than we can.
0:09:32 > 0:09:34That's so cool!
0:09:34 > 0:09:37Of course, they have to go and take it one step further
0:09:37 > 0:09:40and dive down as deep as 90 metres.
0:09:40 > 0:09:42That's the height of Big Ben!
0:09:42 > 0:09:44Is there anything these animals can't do?
0:09:44 > 0:09:46No, not really. They're also deadly.
0:09:46 > 0:09:49Just three drops of their venom can kill eight people.
0:09:49 > 0:09:52- Are you serious?
0:09:52 > 0:09:56OK, they're fast, speedy swimmers and deadly killers.
0:09:56 > 0:10:00I won't be getting too close to these slippery serpents.
0:10:00 > 0:10:03Like the jellyfish, which uses its entire body as a lung,
0:10:03 > 0:10:04sea snakes have no gills,
0:10:04 > 0:10:07but by holding their breath and using bottom breathing,
0:10:07 > 0:10:09they have found their own unique way
0:10:09 > 0:10:11of staying underwater for a very long time.
0:10:11 > 0:10:14So, both the sea snake and jellyfish have no gills,
0:10:14 > 0:10:15but have found other weird
0:10:15 > 0:10:17and wonderful ways to breathe.
0:10:18 > 0:10:22Umm, why do I get the feeling, that's another bottom?
0:10:22 > 0:10:26Bottom breathing! The sea cucumber also breathes through its bum.
0:10:26 > 0:10:29- It's cool, isn't it?- At least the sea snake is discreet about it.
0:10:29 > 0:10:31Trust you to bring the tone down!
0:10:31 > 0:10:33Hang on! This is all scientific fact, Gem.
0:10:33 > 0:10:36Yeah, well, I think it's just an excuse for you to show
0:10:36 > 0:10:38a disgusting shot of a bottom breathing.
0:10:38 > 0:10:40This had better be good.
0:10:40 > 0:10:42So, look, we've seen fish gills.
0:10:42 > 0:10:45Well, sea cucumbers have gills in their bottoms.
0:10:45 > 0:10:48- Go on.- And, as you might imagine, the water up there
0:10:48 > 0:10:51doesn't have the most delicate of tastes.
0:10:51 > 0:10:55Oh, now, this is already too much information, but we've come this far.
0:10:55 > 0:10:58To ensure the oxygen he gets from the water
0:10:58 > 0:11:00is a little more satisfactory, he has to breathe
0:11:00 > 0:11:03in and out of his bottom to get a clean flow of water.
0:11:03 > 0:11:05I'm with that fish - not impressed!
0:11:05 > 0:11:07Why not? The sea snake does it, too!
0:11:07 > 0:11:10Hmmm, anyway, let's get back
0:11:10 > 0:11:11to the real connections.
0:11:11 > 0:11:13Who else links to the sea snake?
0:11:14 > 0:11:17Oh, no! What's that coming out of the mud?
0:11:17 > 0:11:20This better not have anything to do with bottoms again.
0:11:20 > 0:11:22- Now, would I? - Well, yes, you would.
0:11:22 > 0:11:25No, this is just an innocent little mud lobster.
0:11:25 > 0:11:27And, yes, he is actually a lobster!
0:11:27 > 0:11:30He lives a normal life in the mangroves
0:11:30 > 0:11:32building mountainous piles of mud.
0:11:32 > 0:11:35What? He's responsible for that pile of mud?
0:11:35 > 0:11:37Yep, it's his favourite pastime.
0:11:37 > 0:11:39He can build them as high as me.
0:11:39 > 0:11:41Whoa! Not bad for a critter that size!
0:11:41 > 0:11:44That would be like us building a cathedral all on our own!
0:11:44 > 0:11:46I know, it's cool stuff.
0:11:46 > 0:11:50Hang on, though, don't lobsters usually live underwater?
0:11:50 > 0:11:53They do indeed. Yes, lobsters have gills like fish,
0:11:53 > 0:11:56but Mr mud shack has found a way to keep breathing on land,
0:11:56 > 0:11:58so he can keep up his mud mounding.
0:11:58 > 0:12:01What does he breathe, then? Mud?
0:12:01 > 0:12:04No, one of the reasons he delves through all this dirt
0:12:04 > 0:12:07is to create a little burrow just below the waterline.
0:12:07 > 0:12:09That way he always has a little pool of water to bathe in,
0:12:09 > 0:12:11and as long as his gills stay wet,
0:12:11 > 0:12:14he can then breathe in oxygen from the air.
0:12:14 > 0:12:16Another evolutionary wonder!
0:12:16 > 0:12:19A lobster that has learned to live on land by breathing air,
0:12:19 > 0:12:22and a land snake that's learned to live in the sea
0:12:22 > 0:12:25- by breathing through its bottom! - The wonders of the Barrier Reef!
0:12:25 > 0:12:27Both the sea snake and the mud lobster
0:12:27 > 0:12:28have learnt to breathe air
0:12:28 > 0:12:30in different ways to survive.
0:12:30 > 0:12:32OK, who's next?
0:12:32 > 0:12:34Forests? In the Barrier Reef?
0:12:34 > 0:12:36Yeah, these are mangroves again.
0:12:36 > 0:12:38They're kind of small forests along the coastline
0:12:38 > 0:12:40and on islands in the Barrier Reef.
0:12:40 > 0:12:43I'm no tree expert, but I don't get how trees
0:12:43 > 0:12:47manage to grow here. There's just lots of sloppy wet mud,
0:12:47 > 0:12:51and don't they need fresh water and not salty sea water?
0:12:51 > 0:12:54OK, here's the science bit. Listen and learn.
0:12:54 > 0:12:57Usually trees take their air from the soil to breathe,
0:12:57 > 0:13:01but the mangrove trees have adapted their roots to act as snorkels.
0:13:01 > 0:13:04Snorkels, Dr Barnacles?
0:13:04 > 0:13:07Yes, Gemma. They take in gases from the air rather than the soil
0:13:07 > 0:13:10through loads of tiny little holes in their snorkel roots
0:13:10 > 0:13:15that don't allow water and salt in, but do let in the air.
0:13:15 > 0:13:18A three metre tree can have as many as 10,000 of these snorkels.
0:13:18 > 0:13:21Hmmm, I'm not sure I buy this one, Dr Barnacles.
0:13:21 > 0:13:23Well, let me explain further, young lady.
0:13:23 > 0:13:27When the tide is low, they take in air through their snorkel roots.
0:13:29 > 0:13:31And when the tide is high,
0:13:31 > 0:13:35they can store air in the roots like lots of little air pockets.
0:13:35 > 0:13:39Ah, no wonder it's such a popular hangout!
0:13:39 > 0:13:41Mangroves make up a real living community
0:13:41 > 0:13:44where all sorts of animals choose to live together
0:13:44 > 0:13:46on a temporary or long-term basis.
0:13:46 > 0:13:50Crabs, jellyfish, lobsters, fish, reptiles, birds
0:13:50 > 0:13:52and lots of opportunities for mud fights!
0:13:52 > 0:13:54Mud soaked mangroves and muddy lobsters!
0:13:54 > 0:13:58- No prizes for guessing the connection!- Exactly - mud living!
0:13:58 > 0:14:00Now, that sounds like fun!
0:14:02 > 0:14:06Boo! Umm, look behind you, there's a shark!
0:14:06 > 0:14:09Umm, are you alive?
0:14:09 > 0:14:10Hello!
0:14:10 > 0:14:13Ah, the mud skipper, one of the weirdest, boggle eyed,
0:14:13 > 0:14:15mud-loving animals in the Barrier Reef.
0:14:15 > 0:14:17He'd out-stare anyone, this geezer!
0:14:17 > 0:14:19TICKING
0:14:21 > 0:14:22BELL
0:14:22 > 0:14:25Aw, OK, you win, mud skipper!
0:14:25 > 0:14:26Yeah!
0:14:26 > 0:14:30What's even weirder is that when they do decide to move,
0:14:30 > 0:14:32they're super quick! Where's he gone?
0:14:32 > 0:14:33Yeah, they are very weird.
0:14:33 > 0:14:36They're like statues one minute and gone the next!
0:14:36 > 0:14:39In fact, they're multi-talented. These little critters can jump,
0:14:39 > 0:14:42skip, walk and climb and on land they use their fins
0:14:42 > 0:14:44to move about in little hops.
0:14:44 > 0:14:49Or skips, like their name. But, are they fish or froggy type things?
0:14:49 > 0:14:51they're fish, but they've adapted to being on land.
0:14:51 > 0:14:54some of them spend almost all their time living on land,
0:14:54 > 0:14:58returning to water just to fill up storage gills so they can breathe.
0:14:58 > 0:15:02Ah! So, they carry around their own little oxygen water tanks? Cool!
0:15:02 > 0:15:04I know, and they can also breathe through their skin,
0:15:04 > 0:15:08so they keep their tails in water and roll around in puddles
0:15:08 > 0:15:09to keep their skin wet.
0:15:09 > 0:15:11The mangrove trees and the mud skipper -
0:15:11 > 0:15:13both lucky enough to have their own
0:15:13 > 0:15:15personal breathing equipment.
0:15:15 > 0:15:16The trees with their air pockets,
0:15:16 > 0:15:17and the mud skipper
0:15:17 > 0:15:19with their water storage gills.
0:15:21 > 0:15:22OK, this is spooky.
0:15:22 > 0:15:25I can't see anything, but I think I can hear a spaceship.
0:15:25 > 0:15:27Well, some alien life form.
0:15:27 > 0:15:31What you're hearing is the very space age sound of the minke whales.
0:15:31 > 0:15:34Ah, so, what? Whales talk to each other?
0:15:34 > 0:15:36Some do, yes. Kind of.
0:15:36 > 0:15:40They don't have vocal chords like us, but they make these sounds
0:15:40 > 0:15:41from the larynx in their throat.
0:15:41 > 0:15:43Why do they talk to each other?
0:15:43 > 0:15:45They just bob around gulping up plankton.
0:15:45 > 0:15:47Why the need for conversation?
0:15:47 > 0:15:50They're very social animals, I guess, and like to say hello.
0:15:50 > 0:15:51What do you think they're saying?
0:16:05 > 0:16:07In fact, they're quite like humans.
0:16:07 > 0:16:09They also breathe like us -
0:16:09 > 0:16:11not through their mouths like some other marine animals,
0:16:11 > 0:16:15but through their nostrils which are located on their backs.
0:16:15 > 0:16:17How come they don't drown like we would?
0:16:17 > 0:16:20They have a specialist skill called free-diving.
0:16:20 > 0:16:22Their lungs aren't enormous,
0:16:22 > 0:16:24but they're really good at soaking in air,
0:16:24 > 0:16:26so when whales take a deep breath...
0:16:27 > 0:16:30..they fill their lungs up with loads of oxygen,
0:16:30 > 0:16:32so each breath lasts longer.
0:16:32 > 0:16:34How come they don't get water up their nostrils?
0:16:34 > 0:16:37Like the sea snakes, they can shut their nostrils off
0:16:37 > 0:16:41so they don't take in any water before they do their deep dives.
0:16:41 > 0:16:44They've been found as deep as 140 metres!
0:16:44 > 0:16:47Wow! That's as deep as the height of the Millennium Wheel!
0:16:49 > 0:16:52Isn't it weird how trees in the mud and deep diving whales
0:16:52 > 0:16:55can be linked because they both breathe in the same way?
0:16:55 > 0:16:57I know! Mangroves and minke whales
0:16:57 > 0:16:59are connected because they both
0:16:59 > 0:17:01breathe air, not water.
0:17:01 > 0:17:03Ah, look, it's Flipper!
0:17:03 > 0:17:07Dolphins are so cool, for many reasons. They swim brilliantly,
0:17:07 > 0:17:09they're great divers,
0:17:09 > 0:17:13but they also have amazing hearing, ten times better than us.
0:17:13 > 0:17:14What?
0:17:14 > 0:17:16I said, ten times better than us.
0:17:16 > 0:17:19- Wow!- Very funny.
0:17:19 > 0:17:21Why do they need to hear so well?
0:17:21 > 0:17:23They send out sound, or sonar clicks
0:17:23 > 0:17:26that are bounced back when the sound hits an object.
0:17:26 > 0:17:27That's how they navigate.
0:17:27 > 0:17:29That's weird. We've got to try it.
0:17:29 > 0:17:31Uh-uh-uh! Uh-uh-uh! Uh-uh-uh!
0:17:31 > 0:17:32Uh-uh-uh!
0:17:32 > 0:17:35Hrrrrhh! Hrrrrhh!
0:17:35 > 0:17:37Uh-uh-uh! Uh-uh-uh!
0:17:37 > 0:17:40Hrrrrhhh! Hrrrrhhh!
0:17:40 > 0:17:44Uh-uh-uh! Uh-uh-uh! Uh-uh-uh!
0:17:44 > 0:17:46- This isn't working really, is it? - No, not really.
0:17:46 > 0:17:48Shall we get a cup of tea?
0:17:48 > 0:17:49Uh-uh-uh-uh!
0:17:49 > 0:17:50What does that mean?
0:17:50 > 0:17:51Two sugars, please!
0:17:51 > 0:17:54So, not as easy as it looks, eh?
0:17:54 > 0:17:56Everyone loves dolphins,
0:17:56 > 0:17:59but few people know just how multi-skilled they are.
0:17:59 > 0:18:01They're super-duper intelligent.
0:18:01 > 0:18:02Yeah!
0:18:02 > 0:18:06They can swim fabulously fast, flip fantastically in the air
0:18:06 > 0:18:07and totally talk,
0:18:07 > 0:18:11plus have brilliantly breathtaking breathing methods.
0:18:11 > 0:18:13Don't they breathe through that blowhole?
0:18:13 > 0:18:17No, it's like a giant nostril and as the dolphin breathes out,
0:18:17 > 0:18:22the air can leave the nostrils at speeds of over 160 mph.
0:18:22 > 0:18:24What? That's the speed of a racing car!
0:18:24 > 0:18:26Yeah, because like us, getting water in their nostrils
0:18:26 > 0:18:28would mean they'd drown,
0:18:28 > 0:18:31they have powerful muscles that close the blowhole
0:18:31 > 0:18:32and they dive under again.
0:18:32 > 0:18:35They must do this quickly. They're constantly up and under.
0:18:35 > 0:18:37A dolphin can empty and refill its lungs
0:18:37 > 0:18:39in less than a fifth of a second.
0:18:39 > 0:18:41That's literally in the blink of an eye!
0:18:41 > 0:18:43We're going to cut to a picture of me blinking!
0:18:43 > 0:18:47Our delightful dolphins are linked to our magnificent minkes
0:18:47 > 0:18:49because they both have nostrils
0:18:49 > 0:18:50on top of their heads to breathe.
0:18:52 > 0:18:55OK, let's take a look back over our breathing connections.
0:18:58 > 0:19:01Now, imagine being almost completely made of water
0:19:01 > 0:19:05and breathing throughout your whole body, like our soggy jellyfish.
0:19:05 > 0:19:08For me, nothing is as weird as our bottom breathing sea snake.
0:19:08 > 0:19:10I mean, he can hold his breath really well, too,
0:19:10 > 0:19:12but bottom breathing?
0:19:13 > 0:19:14Hang on a sec.
0:19:15 > 0:19:17BURBLING
0:19:19 > 0:19:20No, doesn't work for me.
0:19:20 > 0:19:22And my bum's a little wet.
0:19:22 > 0:19:24But, at least sea snakes are discreet about it,
0:19:24 > 0:19:27unlike the sea cucumbers. Those guys have got no shame.
0:19:27 > 0:19:29At least they have lots of water,
0:19:29 > 0:19:32unlike the poor mud lobster who has to build mud pies
0:19:32 > 0:19:33to be able to breathe.
0:19:33 > 0:19:35What about our weird air breathing trees?
0:19:35 > 0:19:37- They've got snorkels as roots. - Oh, yeah!
0:19:37 > 0:19:42Or the even weirder muddy mud skipper who has little water storage tanks?
0:19:42 > 0:19:45Let's not forget our mega-divers - the minke whales,
0:19:45 > 0:19:46and their cousins the dolphins.
0:19:46 > 0:19:49- They breathe out of their backs! - Wow! But, hang on a second -
0:19:49 > 0:19:50what about us humans?
0:19:50 > 0:19:52How do we breathe underwater?
0:19:58 > 0:20:01- I feel like Catwoman in this!- Well, then, that would make me Batman!
0:20:01 > 0:20:03We are dressed like this for a reason.
0:20:03 > 0:20:06We're not lucky enough to be able to breathe underwater.
0:20:06 > 0:20:08Our lungs aren't designed to do that.
0:20:08 > 0:20:12So, we get a bit of help from our very own special air supply -
0:20:12 > 0:20:15attached to this jacket. If you could put it on, Gem.
0:20:15 > 0:20:18I'm going to give you something very special now.
0:20:18 > 0:20:22That is your regulator. That means that you can breathe underwater.
0:20:22 > 0:20:24NOISY BREATHING
0:20:25 > 0:20:27Brilliant! I sound like Darth Vader!
0:20:27 > 0:20:29Last one in is a moray eel!
0:20:29 > 0:20:33Oh, hang on a sec! Oh, wait! Gem, that's cheating! Hang on!
0:20:50 > 0:20:54That was amazing! I actually felt like a fish!
0:20:54 > 0:20:56I think I am a fish!
0:20:56 > 0:20:59- Were you wondering why we didn't come floating to the surface?
0:20:59 > 0:21:02I did, but I'm thinking these weight belts helped us.
0:21:02 > 0:21:06They did. When we breathe in, our lungs fill with air and we move up.
0:21:06 > 0:21:09When we breathe out, we expel air and we sink.
0:21:09 > 0:21:12We use these weights to keep us at the same level as the fish.
0:21:12 > 0:21:15But not just the weights, we also have to use this very clever device.
0:21:15 > 0:21:19It looks a like a life jacket, but it's a buoyancy control device
0:21:19 > 0:21:22and it helps you float by pressing the blue button to fill it with air.
0:21:22 > 0:21:25Then you press the top button, the black one,
0:21:25 > 0:21:27to expel all the air so you can sink.
0:21:27 > 0:21:30A combination of weights and the BCD
0:21:30 > 0:21:32helps us to stay at the same level as the fish.
0:21:32 > 0:21:33What's the connection?
0:21:33 > 0:21:37Our connection is with dolphins - we both take air from the surface
0:21:37 > 0:21:38and take it under the water.
0:21:38 > 0:21:40The only difference is how we use it.
0:21:40 > 0:21:43Dolphins hold their breath. We breathe using these scuba tanks.
0:21:43 > 0:21:45The connection is
0:21:45 > 0:21:46we both breathe air.
0:21:46 > 0:21:49OK, who's next?
0:21:49 > 0:21:52So, how do fish manage to stay afloat and move around?
0:21:52 > 0:21:55They don't have a buoyancy control device.
0:21:55 > 0:21:57Well, they have their very own internal BCD.
0:21:57 > 0:21:59It's called a swim bladder.
0:21:59 > 0:22:03Ah, so, we're wearing all the scuba diving gear to copy what the fish do.
0:22:03 > 0:22:05- For the most part, yeah.- Ah!
0:22:05 > 0:22:08Their swim bladder is like the BCD we're wearing.
0:22:08 > 0:22:10It lets the fish hover and swim effortlessly.
0:22:10 > 0:22:12Their bodies are made of solid muscle.
0:22:12 > 0:22:15Without this swim bladder they'd sink like a stone.
0:22:15 > 0:22:18But, hang on, who pumps up their BCD?
0:22:18 > 0:22:23Well, that's the thing. You see, they control their BCD with gas.
0:22:25 > 0:22:27When they increase the gas, they rise a bit
0:22:27 > 0:22:30and when they decrease the gas, they sink a bit.
0:22:30 > 0:22:33Hang on, so they use gas, like, that kind of gas?
0:22:33 > 0:22:35Not quite, but, yeah, it's similar.
0:22:35 > 0:22:38Urgh! Thank goodness we've got one of these!
0:22:38 > 0:22:41I know, if you did one in your wetsuit, it would never escape!
0:22:41 > 0:22:43Oh, hang on a minute!
0:22:43 > 0:22:45- PARP! - Oh, ho!
0:22:45 > 0:22:47That's been in there for hours!
0:22:47 > 0:22:49So, fish are linked to scuba divers
0:22:49 > 0:22:51by buoyancy control.
0:22:53 > 0:22:55Meet the hawkfish.
0:22:55 > 0:23:00Aww, he's very pretty. Is he likely to swim any time soon?
0:23:00 > 0:23:03Nope. Despite being born a fish, he's not been blessed
0:23:03 > 0:23:06with the ideal equipment to swim off with his fishy friends.
0:23:06 > 0:23:08But, he looks relatively normal.
0:23:08 > 0:23:11Well, he is, except for his lack of a swim bladder.
0:23:11 > 0:23:14That means it's really hard for him to swim,
0:23:14 > 0:23:16so he tends to pick a branch of coral to perch on
0:23:16 > 0:23:17and watch the reef go by.
0:23:17 > 0:23:20This is one of his relatives, the arc eye hawkfish.
0:23:20 > 0:23:23So, he has fish scales, fins and all the rest,
0:23:23 > 0:23:27but he can't swim very well? That's weird.
0:23:27 > 0:23:29That's how important buoyancy is in the ocean.
0:23:29 > 0:23:33Most marine animals have something to help them get around,
0:23:33 > 0:23:34but there's the odd fellow like this
0:23:34 > 0:23:36with nothing to help him stay afloat.
0:23:36 > 0:23:39It looks like he's got a hawk's eye view of the reef to me!
0:23:39 > 0:23:40Ha-ha-ha!
0:23:40 > 0:23:41What an odd pair, though.
0:23:41 > 0:23:45We've got one fishy floater and one that sinks like a stone.
0:23:45 > 0:23:46Swim bladder is the connection
0:23:46 > 0:23:48between the cardinalfish
0:23:48 > 0:23:49and the hawkfish.
0:23:51 > 0:23:54Our next sea oddity is a cephalopod.
0:23:54 > 0:23:57A whatalopod? Are you sure it's alive, by the way?
0:23:57 > 0:24:00A cephalopod? Ah, yes, it's alive.
0:24:00 > 0:24:05His relatives have been alive for more than 400 million years!
0:24:05 > 0:24:07Huh?
0:24:07 > 0:24:08400 million?
0:24:08 > 0:24:11Wow! What kind of moisturiser does he use? He looks great!
0:24:11 > 0:24:16This is a nautilus. One of the ocean's most ancient creatures.
0:24:16 > 0:24:19It's very weird, and you still haven't told me
0:24:19 > 0:24:21- what cellophane-pod is.- A cephalopod!- Yes!
0:24:21 > 0:24:25It means head, foot. They're molluscs.
0:24:25 > 0:24:29Soft, squishy animals whose heads are attached to their modified feet.
0:24:29 > 0:24:30I can't make head or foot of that!
0:24:30 > 0:24:34Ha ha! Well, it's all tucked into the shell and they do have a head
0:24:34 > 0:24:36because that's where their eyes are.
0:24:36 > 0:24:38They don't look like they've good eyesight
0:24:38 > 0:24:39bobbing around like that.
0:24:39 > 0:24:41It's amazing these guys can see at all.
0:24:41 > 0:24:44For starters, they're very old and could probably see
0:24:44 > 0:24:45before anything else could.
0:24:45 > 0:24:49Secondly, they can live up to 600 metres deep.
0:24:49 > 0:24:52Wow! They look a bit like spacemen bobbing around!
0:24:52 > 0:24:56They're moving gases around their little chamber shell to keep afloat.
0:24:56 > 0:24:57Eh?
0:24:57 > 0:24:58Well, that's charming!
0:24:58 > 0:25:00Clever use of gas, though.
0:25:00 > 0:25:02With their ingenious use of gas,
0:25:02 > 0:25:05and a clever bit of jet propulsion, they can journey quite far.
0:25:05 > 0:25:09Our space-like nautilus and clumsy hawkfish are connected
0:25:09 > 0:25:10by their lack of a swim bladder,
0:25:10 > 0:25:12and connect back
0:25:12 > 0:25:13to our first big breather,
0:25:13 > 0:25:14the potato cod,
0:25:14 > 0:25:16because they both have gills!
0:25:20 > 0:25:22From bottom breathing, to trees with snorkels,
0:25:22 > 0:25:26breathing in the underwater world is both mind boggling and bizarre.
0:25:26 > 0:25:29- Hey, shall we do this last Reefcap in one breath?- In one breath?
0:25:29 > 0:25:32- Yeah!- The whole lot?- Yeah! - OK, yeah.- Ready?- Yeah.
0:25:33 > 0:25:36What a collection! It's enough to take my breath away.
0:25:36 > 0:25:38We started in a logical place with the fish.
0:25:38 > 0:25:40They breathe through their gills. Easy.
0:25:40 > 0:25:43They make it look cool, unlike eels who have to gulp to breathe.
0:25:43 > 0:25:45It looks like they're always talking.
0:25:45 > 0:25:48Then you've got the magnificent manta rays.
0:25:48 > 0:25:50They show off with ten gills and cool moves.
0:25:50 > 0:25:52The squat lobsters are always twitching
0:25:52 > 0:25:55to push the water over their shell gills to breathe.
0:25:55 > 0:25:57Like the barnacle. With a similar technique,
0:25:57 > 0:26:00he breathes through his feet. I hope they don't smell!
0:26:00 > 0:26:02There might be lots of wobbling,
0:26:02 > 0:26:05but jellyfish don't even have to try!
0:26:05 > 0:26:07They just soak the oxygen up through the water.
0:26:07 > 0:26:11Our snake is an easy diver, but he can also breathe through his bum.
0:26:11 > 0:26:15Not as much as the sea cucumber, though. He's a proper bottom gulper!
0:26:15 > 0:26:17- Gross!- Well, it's not his fault.
0:26:17 > 0:26:19He might not be the cleanest critter around,
0:26:19 > 0:26:23but I reckon the mud lobster has most fun with his mud mansions.
0:26:23 > 0:26:26Well, he is living in exclusive mangroves where trees don't grow
0:26:26 > 0:26:30from the soil, but through snorkel-like holes in the roots.
0:26:30 > 0:26:32A breathing tree! It's very Lord Of The Rings!
0:26:32 > 0:26:35Mud skippers don't think twice about leaving the water
0:26:35 > 0:26:36to play in the mud.
0:26:36 > 0:26:38Minke whales take a deep breath
0:26:38 > 0:26:40and dive down the height of the Millennium Wheel.
0:26:40 > 0:26:41That is free diving!
0:26:41 > 0:26:43Then there were the diving dolphins,
0:26:43 > 0:26:45with their one giant nostril.
0:26:45 > 0:26:48Humans have tried, too, but nature does it better.
0:26:48 > 0:26:50We have to use breathing and buoyancy aids
0:26:50 > 0:26:52to help us swim with the fishes.
0:26:52 > 0:26:54We just don't look as cool though, do we?
0:26:54 > 0:26:56At least we don't rely on our own gas to keep us afloat.
0:26:56 > 0:26:59I wouldn't want to get too close to the cardinalfish
0:26:59 > 0:27:01with his big gassy bladder. Ooh!
0:27:01 > 0:27:03The alternative is no transportation at all.
0:27:03 > 0:27:07The poor hawk-eyed hawkfish can't move very far and has to sit there
0:27:07 > 0:27:08and watch the world go by!
0:27:08 > 0:27:11Unlike the ancient yoyo-like nautilus. They bounce up and down
0:27:11 > 0:27:14because they have their very own gas filled shell chamber.
0:27:14 > 0:27:17A bit like jet propelled spaceships!
0:27:17 > 0:27:19Whoo! What a line-up! Give me some air!
0:27:21 > 0:27:24So, something we take for granted like breathing
0:27:24 > 0:27:26is a different ball game for our ocean creatures.
0:27:26 > 0:27:28I know! From extreme breath holding
0:27:28 > 0:27:31to trees that breathe, they certainly show us how it's done.
0:27:31 > 0:27:36And as for the sea cucumber breathing out of his bottom - how weird!
0:27:36 > 0:27:37BURBLING
0:27:37 > 0:27:41Actually, Barney, how did you manage to do all that in one breath?
0:27:41 > 0:27:43And what are you doing?
0:27:43 > 0:27:45Umm, nothing!
0:27:45 > 0:27:48I wasn't trying to breathe like a sea cucumber or anything.
0:27:48 > 0:27:52I was just playing in the water, me. That's all I'm doing.
0:28:00 > 0:28:03Subtitles by Red Bee Media Ltd
0:28:03 > 0:28:06E-mail subtitling@bbc.co.uk