0:00:02 > 0:00:05Australia, home of the possum, cool surfer dudes, strange lingo...
0:00:05 > 0:00:06"fair dinkum."
0:00:06 > 0:00:08Lots 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 miniscule to the mammoth, to the miraculous, they're all
0:00:22 > 0:00:24connected in Barney's Barrier Reef.
0:00:46 > 0:00:50- Foggy mask, can't see!- I've lost my goggles... I can't see either!
0:00:50 > 0:00:52This is why to see clearly underwater you've gotta have
0:00:52 > 0:00:55a well-fitting mask, or one that's really clear and even then,
0:00:55 > 0:00:58what you see underwater is still distorted.
0:00:58 > 0:00:59I'll prove the point. Gem...
0:00:59 > 0:01:01- Yeah.- What colour are my shorts?
0:01:01 > 0:01:03- Don't know... I'm busy looking at fishes.
0:01:03 > 0:01:06I'll do a dive, have a look and just tell me what colour they are.
0:01:11 > 0:01:14- Brown, definitely brown, yeah. - Are you sure?
0:01:14 > 0:01:18I'll tell you what, I'll dive down, you have another look.
0:01:20 > 0:01:22Ah, OK, they're red.
0:01:22 > 0:01:24Here comes the science bit. Now the reason they're red is
0:01:24 > 0:01:27because the further down you go, the more colours disappear.
0:01:27 > 0:01:28What do fish see, then?
0:01:28 > 0:01:30Patterns and colours that we can't see.
0:01:30 > 0:01:33They have either really weird or amazing eyesight and some have
0:01:33 > 0:01:36bizarre ways of checking each other out,
0:01:36 > 0:01:39which leads us very nicely to today's Barney's Barrier Reef.
0:01:39 > 0:01:41I see you baby, shaking that...tail!
0:01:48 > 0:01:51Our first super-sighted species
0:01:51 > 0:01:53is this little fellow... the Damsel fish.
0:01:53 > 0:01:56And Damsel fish are hard to miss, they're very colourful,
0:01:56 > 0:02:00but if fish can see so well, why do they need to be so bright?
0:02:00 > 0:02:02I mean they look good, but why else?
0:02:02 > 0:02:04It's mainly to tell friends from enemies.
0:02:04 > 0:02:06Oh, I guess it's a bit like an outfit
0:02:06 > 0:02:08worn by a whole team or something?
0:02:08 > 0:02:10Exactly, like a football strip, that tells us whether
0:02:10 > 0:02:13someone supports your team or the opposition, it's a bit similar.
0:02:13 > 0:02:16This team might play for Shellsea FC for example...
0:02:16 > 0:02:19Or Swimmerpool United!
0:02:19 > 0:02:21But these markings are a little
0:02:21 > 0:02:24more crucial to their survival than football shirts?
0:02:24 > 0:02:26Yeah, which is why some fish or species have a whole different
0:02:26 > 0:02:29level of vision that really gives them an idea of who's
0:02:29 > 0:02:31on their team and who definitely isn't.
0:02:31 > 0:02:34Don't they just see lots of yellow fish, cos that's all I can see?
0:02:34 > 0:02:37Well, this is the underwater world.
0:02:39 > 0:02:41You've heard of UV light, yeah?
0:02:41 > 0:02:43Yep, it stands for ultraviolet.
0:02:43 > 0:02:46It's the light from the sun that sun lotion protects us against.
0:02:46 > 0:02:48Exactly, well done. Well, Damsel fish can actually
0:02:48 > 0:02:51see ultraviolet light and each fish
0:02:51 > 0:02:54has special markings in ultraviolet that only the others can see.
0:02:54 > 0:02:56Oh, my brain hurts!
0:02:56 > 0:02:59It is a bit technical. Watch this. This is how we see the Damsel fish.
0:02:59 > 0:03:01Ah, pretty, but quite plain, though.
0:03:01 > 0:03:05Exactly, but this is how Damsel fish might see other Damsel fish.
0:03:05 > 0:03:07- Can you see all those patterns? - Oh, yeah!
0:03:07 > 0:03:11- So that's their individual football strip?- Exactly! Cool, isn't it?
0:03:11 > 0:03:14So, our delightful Damsel fish see patterns that we can't see
0:03:14 > 0:03:18at all through their unbelievable ultra-violet eyes. Cool, eh?
0:03:18 > 0:03:21OK. My turn. Here's our super sight contender number two.
0:03:22 > 0:03:26Wake up, mate! Oh, don't mind us we're only presenting a TV show!
0:03:26 > 0:03:32- That's better.- Ah, the crocodile, or should I say croc eye dile!
0:03:32 > 0:03:34Am I to understand from
0:03:34 > 0:03:37that extremely rubbish joke that you know all about his eyesight?
0:03:37 > 0:03:41Yep. This is a saltwater croc, or "salties"
0:03:41 > 0:03:45as the Aussies like to call them. They have pretty good eyesight both
0:03:45 > 0:03:49above and below water, which is partly what makes them so deadly.
0:03:49 > 0:03:53Not forgetting the fact that one croc can weigh as much as 15 people.
0:03:53 > 0:03:55And they wouldn't be so good at hunting if they couldn't
0:03:55 > 0:03:58- see so well now, would they? - So, what's their secret?
0:03:58 > 0:04:00OK. There's one eyelid at the top,
0:04:00 > 0:04:02there's another eyelid at the bottom.
0:04:02 > 0:04:04OK. So far, so normal.
0:04:04 > 0:04:08- And here is a third eyelid. - Third eyelid? That's weird!
0:04:08 > 0:04:11- Why does it need three?- The third one is known as a "nictitating eyelid"
0:04:11 > 0:04:13which means blinking eyelid.
0:04:13 > 0:04:15- Show-off!- Ha ha ha!
0:04:15 > 0:04:17It's a clear eyelid that cleans the eye with fluid
0:04:17 > 0:04:21from the croc's tear ducts. Ever heard the phrase "crocodile tears"?
0:04:21 > 0:04:24I have. OK, so crocodiles do cry?
0:04:24 > 0:04:26Yes, but not because they're sad,
0:04:26 > 0:04:29they're just washing their eyes but their eyelids help them see clearer,
0:04:29 > 0:04:32both on land and underwater, so they can stay very still,
0:04:32 > 0:04:37doing their impression of a log, until they're ready to strike.
0:04:37 > 0:04:40- Goodbye, cute animal. - That was a wallaby.
0:04:40 > 0:04:42You're right there! That WAS a wallaby.
0:04:42 > 0:04:46Its most powerful form of attack is called a "death roll"
0:04:46 > 0:04:48where he grabs his prey and rolls it underwater.
0:04:48 > 0:04:52And nothing is safe from this big guy. I bet he eats anything!
0:04:52 > 0:04:54Yeah, anything and everything,
0:04:54 > 0:04:57including humans, if we get too close.
0:04:57 > 0:05:00Well, I won't be paddling in crocodile creek!
0:05:00 > 0:05:04They don't have a real taste for humans, but can be aggressive.
0:05:04 > 0:05:06One croc hassled some fishermen
0:05:06 > 0:05:09so much it had to be locked in a police cell to calm down!
0:05:09 > 0:05:11Oh, come on! No way! Crocodile criminals!
0:05:11 > 0:05:15If you ask me, their super strong jaws, their super size and their
0:05:15 > 0:05:19speed are enough, without the extra help on the eyesight front.
0:05:19 > 0:05:22Their third eyelid gives them heaps of advantages, both above
0:05:22 > 0:05:24- and underwater. - Oh, this is getting embarrassing!
0:05:24 > 0:05:26Damsel fish can see better than us, as well!
0:05:26 > 0:05:29Yep. The Damsel fish and crocodile are connected because they have
0:05:29 > 0:05:31superhuman sight underwater.
0:05:31 > 0:05:35OK. So, who's our next super-sighted sea dweller?
0:05:37 > 0:05:42Well, I couldn't resist this beautiful graceful turtle.
0:05:42 > 0:05:46Look at him go! Definitely one of the Reef's best swimmers.
0:05:46 > 0:05:50Oh, tell me about it! These guys can swim more than 2000 km in one go...
0:05:50 > 0:05:54that's like swimming all the way round England and Scotland!
0:05:54 > 0:05:57Yeah. In the water, they can see really well, much better than us
0:05:57 > 0:06:01with a special spherical eye lens which they need to see their food.
0:06:01 > 0:06:04So they must qualify as one of the best ocean-lookers!
0:06:04 > 0:06:07Not that kind of looker, obviously!
0:06:08 > 0:06:13Hum... It all goes swimmingly for the turtles until they hit dry land.
0:06:13 > 0:06:16- Why? What happens then? - Well, they're a bit rubbish, really.
0:06:16 > 0:06:17They become short-sighted,
0:06:17 > 0:06:20and have a habit of not looking where they're going.
0:06:24 > 0:06:27Aagh! Well, I would offer to give them a lift back up,
0:06:27 > 0:06:30but they weigh 160 kg... that's the same as 40 cats!
0:06:30 > 0:06:35- Or one very big one!- So how do they link to the sharp-eyed croc?
0:06:35 > 0:06:38They're connected because they can see above and below water.
0:06:38 > 0:06:40OK, so turtles have a mini-link to the croc,
0:06:40 > 0:06:43but who is our main croc connection?
0:06:44 > 0:06:47Hang on! Where's all the water gone?
0:06:47 > 0:06:48These are mangroves...
0:06:48 > 0:06:51they're kind of small forests near the edge of the Barrier Reef.
0:06:51 > 0:06:54They hold the coastlines and islands together
0:06:54 > 0:06:55to stop dirt spilling into the ocean.
0:06:57 > 0:07:01- What are you looking at?- More importantly, what are we looking at?
0:07:01 > 0:07:04Is it a shrimp, a newt, a fish?
0:07:04 > 0:07:08He is a Mudskipper... now these truly are fish out of water!
0:07:10 > 0:07:11Hey?
0:07:11 > 0:07:14He's a fish, but they live out of water for most of the time.
0:07:14 > 0:07:16They have a technique of holding water in their mouth
0:07:16 > 0:07:19and gills which allows them to breathe on land.
0:07:19 > 0:07:22- They can also breathe through their skin.- Breathe through their skin?
0:07:22 > 0:07:25- That's a new one! - For fish, they're pretty rubbish
0:07:25 > 0:07:28at swimming and that's why they do this weird skip-hop movement.
0:07:28 > 0:07:31A-ha! Mud skippers... now I get it!
0:07:31 > 0:07:33See, there you go, and if they were held underwater,
0:07:33 > 0:07:36some could drown, because they need air to breathe.
0:07:36 > 0:07:39That is so weird. I've never heard of a fish that's scared of water!
0:07:39 > 0:07:43But Gem, the best thing about these guys... their eyesight.
0:07:43 > 0:07:47And they certainly have big eyes for little creatures!
0:07:47 > 0:07:49They're funny-looking things, aren't they?
0:07:49 > 0:07:52With their fat necks and googly, rainbow-coloured eyes?
0:07:52 > 0:07:55And those googly rainbow eyes are on stalks. They have 200 degree vision
0:07:55 > 0:07:59of the world... in other words, they can see in panoramic vision.
0:08:00 > 0:08:03You mean they can basically watch their own backs?
0:08:03 > 0:08:06Yeah, without even a tiny turn of the head. And, like the croc,
0:08:06 > 0:08:09their eyes are designed to see both under and above the water.
0:08:09 > 0:08:13Cool for a critter about 100,000 smaller than the croc!
0:08:16 > 0:08:20The Mantis Shrimp, cleaning out his hole, again.
0:08:20 > 0:08:22He's a busy little thing, isn't he?
0:08:22 > 0:08:24- Oh, look, he's waving. Hello!- Hello!
0:08:24 > 0:08:27As well as being the ocean's tidiest creature, take a close
0:08:27 > 0:08:30look and you'll find out that he's not just any old shrimp.
0:08:30 > 0:08:33Well, this one looks like an alien, from a certain angle!
0:08:33 > 0:08:35Those eyes may look like mini microphones...
0:08:35 > 0:08:40testing, testing, but they're busy checking out everything around them.
0:08:42 > 0:08:45He has the eyesight that superheroes could only dream of.
0:08:45 > 0:08:47Each eye can move on its own
0:08:47 > 0:08:52and they have 360 degree vision, so they can see all around them.
0:08:52 > 0:08:53Each has three pupils.
0:08:53 > 0:08:56With this, he can see things broken down
0:08:56 > 0:08:58- into three overlapping fields of vision.- Do you know what?
0:08:58 > 0:09:02His eyes are so super-techno he can't even fit them in his head!
0:09:02 > 0:09:05It's the central pupil that has the real super-vision.
0:09:05 > 0:09:08It scans an area and colours the image in and kind of
0:09:08 > 0:09:11refreshes the other two pupils, so they work well together
0:09:11 > 0:09:13as a kind of team super-eye.
0:09:13 > 0:09:17And what's more, his world is in proper technicolour.
0:09:17 > 0:09:20Now we see the world through three different colour palettes,
0:09:20 > 0:09:22and so we would see that bird in the tree like this.
0:09:24 > 0:09:26Now when it comes to shrimps, they have twelve different
0:09:26 > 0:09:29colour palettes, and it's impossible to work out exactly
0:09:29 > 0:09:33what they see, but it could be something like this.
0:09:35 > 0:09:39So, if my mathematical calculations are correct, he sees things at least
0:09:39 > 0:09:41four times better than we do.
0:09:41 > 0:09:44They can see colours we don't even know exist. Wow!
0:09:44 > 0:09:48I guess it might be like kind of watching HD TV in 3D vision.
0:09:48 > 0:09:51Yeah, kind of, although we'll probably never know
0:09:51 > 0:09:54exactly how they see the world... And combine this super-power with
0:09:54 > 0:09:57a punch faster than a speeding bullet makes this super-shrimp
0:09:57 > 0:09:59small but pretty deadly.
0:09:59 > 0:10:02As this crab is about to find out!
0:10:03 > 0:10:06Not only does he have the best eyesight in the ocean,
0:10:06 > 0:10:08but one of the best in the animal kingdom.
0:10:08 > 0:10:12Not bad for something which grows to about the size of a pencil.
0:10:12 > 0:10:16If this shrimp was human, he'd be a superhero, or a super-villain.
0:10:16 > 0:10:19Or very, very scary and kill us all!
0:10:19 > 0:10:22And you thought the Mudskipper was cool because he could see all
0:10:22 > 0:10:26around him, so our super-seeing shrimp is connected to the
0:10:26 > 0:10:29panoramic Mudskipper through his amazing super-human eyesight.
0:10:29 > 0:10:32Step up our next contender.
0:10:32 > 0:10:34From a shrimp with super-power sight
0:10:34 > 0:10:37to the Pistol Shrimp that can barely see.
0:10:37 > 0:10:40That's the wonderful and weird world of the ocean for you.
0:10:40 > 0:10:41Are you sure he can't see? He's
0:10:41 > 0:10:45making a good job of digging up the sand for something with no eyesight!
0:10:45 > 0:10:48Well, that's only because he has his buddy -the Goby Fish -
0:10:48 > 0:10:51- keeping watch for him.- What? The fish and shrimps are mates?
0:10:51 > 0:10:54- I thought the fish were just hanging out?- No. These two are bezzy mates.
0:10:54 > 0:10:57The shrimp lives in a burrow in the sand, along with the Goby.
0:10:57 > 0:10:59Looks like the shrimp is doing all the work.
0:10:59 > 0:11:01The Goby's watching for danger...
0:11:01 > 0:11:03that's why he's nicknamed "the Watchman Goby".
0:11:03 > 0:11:06The shrimp has really bad eyesight, so the Goby sees for him.
0:11:06 > 0:11:09Assuming they can't speak, well you never know in this
0:11:09 > 0:11:12weird watery world, how does the shrimp know what's going on?
0:11:12 > 0:11:17Well, the shrimp contacts the Goby using his antennae, and when danger
0:11:17 > 0:11:18approaches, the Goby flicks
0:11:18 > 0:11:21the shrimp with his tail and they dive for cover in the hole.
0:11:21 > 0:11:24But he's not as brave as our boxing Mantis Shrimp though, is he?
0:11:24 > 0:11:26So our shrimp is connected to our shrimp,
0:11:26 > 0:11:30one has superhuman sight, but the other uses his mate to help him see.
0:11:30 > 0:11:34Time for a reef-cap of our creatures who see, and who want to be seen.
0:11:34 > 0:11:37So, we started at the Damsel Fish and got all
0:11:37 > 0:11:39the way to the Blind Pistol Shrimp.
0:11:42 > 0:11:45Let's talk about the Damsel Fish, Gem.
0:11:45 > 0:11:48What makes these guys stand out so clearly to their mates?
0:11:48 > 0:11:51- Easy... their beautiful ultraviolet markings. Amazing.- Oh, yes!
0:11:51 > 0:11:54But what's so special about our croc eye dile...
0:11:54 > 0:11:58That's the second time you've used that joke, that's too many times!
0:11:58 > 0:12:02- Well, our crocodile here has a third eyelid, isn't that right?- Yes.
0:12:02 > 0:12:05And that means they can see above and under the water. Is that true?
0:12:05 > 0:12:09- Yes.- Like the turtle, but bless him, he's rubbish on land!
0:12:09 > 0:12:12- OK. Who came next?- Easy. The big-eyed and fat-necked
0:12:12 > 0:12:15tiny Mudskipper with his panoramic vision of land and sea. Your turn.
0:12:15 > 0:12:18OK. Next was one of the shrimps.
0:12:18 > 0:12:21Oh, yes, the Mantis Shrimp, with his 3D super-colour vision,
0:12:21 > 0:12:23ludicrously good for a shrimp.
0:12:23 > 0:12:25Which leaves us with our badly-sighted Pistol Shrimp
0:12:25 > 0:12:29who relies on his buddy, the Goby, to tell him when he's in danger.
0:12:29 > 0:12:31Quite a selection. Whoever next?
0:12:31 > 0:12:32I don't know!
0:12:35 > 0:12:38Silent, ghostly and deadly.
0:12:38 > 0:12:41- I'm scared!- One of the most venomous creatures in the world...
0:12:41 > 0:12:43the Box Jellyfish.
0:12:43 > 0:12:47Get out of the water, bikini lady!
0:12:49 > 0:12:51Box Jellies are practically invisible to us,
0:12:51 > 0:12:54which is not so good when you're paddling.
0:12:54 > 0:12:59They have 5,000 million stinging barbs, 60 tentacles and 24 eyes.
0:12:59 > 0:13:0124! Why so many?
0:13:01 > 0:13:05All the better to see you with! They have eyes all around their head.
0:13:05 > 0:13:08So they really do have eyes in the back of their heads?
0:13:08 > 0:13:12- And the sides.- Oh, great! You really don't want something that has 5,000
0:13:12 > 0:13:16million chances of stinging you to be able to see you from every angle!
0:13:16 > 0:13:20What's doubly weird is that despite the fact they don't have a brain,
0:13:20 > 0:13:23they have a pair of eyes on each of their four sides
0:13:23 > 0:13:24that are really similar to human eyes.
0:13:24 > 0:13:26They have a lens, retina and iris...
0:13:26 > 0:13:28it's a bit of a scientific puzzle.
0:13:28 > 0:13:32- No brain, but eyes that can see really well.- I don't understand!
0:13:32 > 0:13:34You're not the only one!
0:13:34 > 0:13:36It's one of those ocean mysteries.
0:13:36 > 0:13:39- OK.- Now this is how they might see,
0:13:39 > 0:13:43- and this is a close-up of a jellyfish eye.- Ooh, weird or what!
0:13:43 > 0:13:47I mean I always thought they were just jelly-like floaty things?
0:13:47 > 0:13:50Far from it, but because Box Jellies use vision to hunt, they're a bit
0:13:50 > 0:13:53lost at night, and that's the best time to find them sleeping.
0:13:55 > 0:13:56That's crazy!
0:13:57 > 0:14:02Box Jellies have 24 eyes and Mantis Shrimps have 3 pupils in each eye.
0:14:02 > 0:14:05So the Box Jelly must be connected to the Mantis Shrimp
0:14:05 > 0:14:07because they both have multiple eyes.
0:14:12 > 0:14:14Aha, the octopus, or "occie"
0:14:14 > 0:14:17- as I like to call him. - Where's he gone?
0:14:17 > 0:14:21Hello, I'm here but I've decided to change colour. Ooh, and again!
0:14:21 > 0:14:23It must be great fun to be able to change colour all the time!
0:14:23 > 0:14:25It looks like he's just showing off!
0:14:25 > 0:14:28Actually he's blending in with his surroundings.
0:14:28 > 0:14:32He's saying "I'm not here, no really, I'm not here. Go away".
0:14:32 > 0:14:35So why does he turn red? He's not blending in now, is he?
0:14:35 > 0:14:39Well, now he's saying OK, so you've found me, but leave me alone.
0:14:39 > 0:14:42Are you saying he's talking through his colour-change?
0:14:42 > 0:14:43- No, don't believe you!- It's true.
0:14:43 > 0:14:46- He communicates through his skin. - Hello!
0:14:46 > 0:14:49But what's even better is that he also sees through it.
0:14:49 > 0:14:52He sees through his skin? Now you're really winding me up!
0:14:52 > 0:14:55OK, well maybe not sees through his skin,
0:14:55 > 0:14:58because that's what his eyes are for, but they can't see colour.
0:14:58 > 0:15:01Well, how can they blend into a background, then, if they don't
0:15:01 > 0:15:03know what colour the background is?
0:15:03 > 0:15:06Well, they can feel different colours through their skin
0:15:06 > 0:15:09and that's how they know how to change, like this guy here.
0:15:09 > 0:15:13His skin is so sensitive he knows exactly when to change colour
0:15:13 > 0:15:15and when to set off his colour alarm bell.
0:15:15 > 0:15:18The yellow and blue means 'back-off, buster. I'm angry'.
0:15:18 > 0:15:22Wow! This guy really does look angry, then! Look at his blue rings!
0:15:22 > 0:15:25They're so bright. They look like they have glitter on them!
0:15:25 > 0:15:29And this is one octopus you really don't want to get on the wrong side
0:15:29 > 0:15:32of... the Blue-Ringed Octopus... one of the most venomous creatures
0:15:32 > 0:15:37in the world. Now those flashing blue rings mean back-off now.
0:15:37 > 0:15:40In fact, don't even think about it - I am very, very dangerous.
0:15:40 > 0:15:44So it's a bit like us going red in the face when we're angry?
0:15:44 > 0:15:46Yeah, well apart from the venomous bit.
0:15:48 > 0:15:53So we had the blobby Box Jellyfish, followed by the wobbly Octopus.
0:15:53 > 0:15:57Exactly. Occie and Box Jelly are linked by their wobbly, soft bodies.
0:15:57 > 0:16:00OK. My turn. Now you think you've seen weird.
0:16:00 > 0:16:01Try this geezer.
0:16:06 > 0:16:08Our next creature is a Cephalopod.
0:16:08 > 0:16:11A what-la-pod? Are you sure it's alive, by the way?
0:16:11 > 0:16:13A Cephalopod and yes, it's alive.
0:16:13 > 0:16:17In fact, his relatives have been alive for the last
0:16:17 > 0:16:19- 100 million years.- 100 million?
0:16:19 > 0:16:20He must have a good moisturiser!
0:16:20 > 0:16:25This is a Nautilus... one of the ocean's most ancient creatures.
0:16:25 > 0:16:28Well, it's very weird and you still haven't told me what it is.
0:16:28 > 0:16:31A Cephalopod. It means "head foot". Their molluscs...
0:16:31 > 0:16:35soft, squishy animals whose heads are attached to their modified feet.
0:16:35 > 0:16:38I'm afraid I can't make head nor foot of this!
0:16:38 > 0:16:39Well, it's all tucked into the shell
0:16:39 > 0:16:42and they do have a head, because that's where their eyes are.
0:16:42 > 0:16:45They don't look like they've got good eyesight.
0:16:45 > 0:16:46Look at them bobbing around like that!
0:16:46 > 0:16:49Well, it's amazing these guys can see at all. For starters,
0:16:49 > 0:16:53they're very old and could see pretty much before anything else
0:16:53 > 0:16:57and secondly, they live up to 600 metres deep.
0:16:57 > 0:17:00That's like twice as high as the Empire State Building!
0:17:00 > 0:17:03I know! So, they live in the dark and they've hardly evolved
0:17:03 > 0:17:07- since they first existed, but they can still see.- How?
0:17:07 > 0:17:10Well, it's through a very small eye, formed like a little pin-hole
0:17:10 > 0:17:14camera. They don't see well, but then they are getting on a bit.
0:17:14 > 0:17:18Their eye doesn't see in focus because it has no lens but it allows
0:17:18 > 0:17:21them to see their food... the little animals that glow in the dark.
0:17:21 > 0:17:24So basically they're weird, floating, ancient shells that
0:17:24 > 0:17:27developed an eye like a pin-hole camera long before cameras were
0:17:27 > 0:17:29even invented. That's kind of weird!
0:17:29 > 0:17:32Yeah, and guess what? Octopuses are Cephalopods, too.
0:17:32 > 0:17:36OK, so the Octopus is linked to the ancient Nautilus because
0:17:36 > 0:17:38they're both "head-foots". Cool!
0:17:40 > 0:17:45These are Giant Clams. They look even bigger when they're open.
0:17:45 > 0:17:48They can weigh the same as three grown men.
0:17:49 > 0:17:52They're molluscs so they're related to the slugs and snails.
0:17:52 > 0:17:55OK, so they're part of the squishy, slimy family?
0:17:55 > 0:17:58They're squishy on the inside but not on the outside.
0:17:58 > 0:18:01No-one really hunts these guys when they're this big
0:18:01 > 0:18:04which is probably why they can live to more than 70 years old.
0:18:04 > 0:18:07Wow, that's impressive! A pensioner clam!
0:18:07 > 0:18:08But that's not the best bit.
0:18:08 > 0:18:12They have not one, not two, but hundreds of eyes.
0:18:12 > 0:18:16Do you know what? I think we might need the assistance of Dr Barnacles.
0:18:17 > 0:18:19OK, here's the science bit.
0:18:19 > 0:18:20Listen and learn.
0:18:20 > 0:18:23Clams are home to the Zooxanthellae.
0:18:23 > 0:18:26Why do they have to make these names so complicated to pronounce?!
0:18:26 > 0:18:29- The Zo what?- The Zooxanthellae, Gemma.
0:18:29 > 0:18:31They're tiny plants that live in several types
0:18:31 > 0:18:35of animals exposed to the sun which makes them solar powered.
0:18:35 > 0:18:36Can we just call them Zo's?
0:18:36 > 0:18:40Sure. So to give the Zo's, as we call them, the light they need,
0:18:40 > 0:18:44the clams push their lips outside their shell into the sunlight.
0:18:44 > 0:18:47That leaves their delicate inside tissue exposed to any fish wanting
0:18:47 > 0:18:52a nibble, but the Clam has these clever cells that can tell slight
0:18:52 > 0:18:55- little light changes.- Ah, like eyes?
0:18:55 > 0:18:57Yes, well very basic eyes,
0:18:57 > 0:18:59but basic's fine when you have hundreds of them.
0:18:59 > 0:19:03When they see a shadow of a passing predator, the clam pulls itself in
0:19:03 > 0:19:07and just to be on the safe side, pushes water out of its siphon.
0:19:07 > 0:19:10Aah, and I thought that was his bottom!
0:19:10 > 0:19:12How come we don't have hundreds of eyes?
0:19:12 > 0:19:15They'd come in really useful, I think.
0:19:15 > 0:19:17The ancient Nautilus has simple eyes, too.
0:19:17 > 0:19:20So the Clam is connected to the Nautilus because they both
0:19:20 > 0:19:24have basic eyes, but they're not the only link to our Nautilus shell.
0:19:25 > 0:19:28During the day, the Barrier Reef is a cheerful place,
0:19:28 > 0:19:30full of animals going about their business.
0:19:30 > 0:19:34From the weird and wacky and playful to the craziest colours...
0:19:34 > 0:19:37but once night falls, it's a whole different ocean.
0:19:38 > 0:19:41And this is when the night owls come out to play.
0:19:41 > 0:19:45Or, in the case of these White-Tipped Sharks, to hunt.
0:19:45 > 0:19:47The White Tips are one of the Reef's most common sharks.
0:19:47 > 0:19:49They're asleep during the day.
0:19:49 > 0:19:52Which is why the Reef looks a lot happier then.
0:19:52 > 0:19:55They have night vision. During the day, the pupil in their eye
0:19:55 > 0:19:58is small, to restrict the amount of light coming through,
0:19:58 > 0:20:00but at night, the pupil gets much larger
0:20:00 > 0:20:02to allow more light in so they can see more.
0:20:02 > 0:20:06And allow them to spot any prey that was silly enough
0:20:06 > 0:20:08not to go to bed earlier.
0:20:08 > 0:20:11Now, sharks are twice as good as cats at seeing in the dark.
0:20:11 > 0:20:13They may only be able to see in black and white,
0:20:13 > 0:20:15but their clever eyes allow them to use the moon,
0:20:15 > 0:20:18stars or any available light to get around.
0:20:18 > 0:20:20White Tips have clever ocean eyes
0:20:20 > 0:20:24that don't need light to see, just like the Nautilus.
0:20:24 > 0:20:27So they must be connected to the Nautilus as they can both
0:20:27 > 0:20:28see in the dark.
0:20:28 > 0:20:33Let's catch up on our ocean wonders so far. Time for another reef-cap.
0:20:36 > 0:20:38So, our super-sighted shrimp
0:20:38 > 0:20:41is linked to another creature with superhuman sight.
0:20:41 > 0:20:44I'm gonna give you a clue. He's deadly and invisible.
0:20:44 > 0:20:45Easy - the Box Jellyfish?
0:20:45 > 0:20:49With 24 eyes, far more than he needs, I'm sure,
0:20:49 > 0:20:51but who is the Box Jelly's wobbly connection?
0:20:51 > 0:20:54The Octopus. He sees through his skin...
0:20:54 > 0:20:56weird, but pretty cool, I think.
0:20:56 > 0:20:58OK. Our Nautilus is connected by the fact
0:20:58 > 0:21:00that he's also just a head and a foot.
0:21:00 > 0:21:02- Head-foot.- Mmm.
0:21:02 > 0:21:05Barney, please tell, what's the proper name for a head-foot?
0:21:05 > 0:21:09Right, that is Cephla, Cephla... Cephla-something.
0:21:09 > 0:21:11- Cephalopod.- Yes, that's it.
0:21:11 > 0:21:14- Failed!- No, but I do remember that the Nautilus also has
0:21:14 > 0:21:18a mini-link to the Clam... both with basic but effective eyesight.
0:21:18 > 0:21:21Our main Nautilus link is of course the shark. Both are insomniacs
0:21:21 > 0:21:26- and can see in the dark.- So, who's our next visionary wonder, I wonder.
0:21:30 > 0:21:32Alien contact has been established.
0:21:34 > 0:21:36Eh? Are we still in the ocean?
0:21:36 > 0:21:40Where's the sea gone? Have you switched the lights off, Gem?
0:21:40 > 0:21:42No, we're still in the ocean depths.
0:21:42 > 0:21:45This is the Flashlight Fish, named after flashlights
0:21:45 > 0:21:48- because they flash their lights at each other.- Like this.
0:21:51 > 0:21:53This means 'hello, chuck'.
0:21:53 > 0:21:54What you can see glowing
0:21:54 > 0:21:57is bi-luminescent pouches underneath the eyes.
0:21:57 > 0:22:01The fish use their glow to find food and communicate with each other.
0:22:01 > 0:22:03Incoming transmission.
0:22:03 > 0:22:05- Can they turn it off?- Yeah.
0:22:05 > 0:22:07Handy, eh? They have a lip that can
0:22:07 > 0:22:11cover their glowing pouch, otherwise predators would gobble them up.
0:22:11 > 0:22:13So they see by flashing each other?
0:22:13 > 0:22:15Like having your own car headlights.
0:22:15 > 0:22:18Cool! It's no wonder they can see so well at night.
0:22:18 > 0:22:22A bit like the White-Tipped Reef Shark that hunt at night, remember?
0:22:22 > 0:22:24I get it. Flashlight Fish see perfectly well in the dark,
0:22:24 > 0:22:27which connects them to the White-Tipped Reef Shark.
0:22:32 > 0:22:35Woah, who's this crazy colour-changer?
0:22:35 > 0:22:37This is a Cuttlefish.
0:22:37 > 0:22:40Like the Octopus, he uses colour-change to communicate.
0:22:40 > 0:22:42Looks like he's talking pretty quickly.
0:22:42 > 0:22:45- He's giving me a headache! - The difference between
0:22:45 > 0:22:48the Octopus and the Cuttlefish is that he is a total show-off!
0:22:52 > 0:22:56I just wish he'd make his mind up what colour he wants to be!
0:22:56 > 0:23:00Well, Cuttlefish certainly make use of their colour-changing skills.
0:23:00 > 0:23:05They use it to blend in, but also to chat and flirt.
0:23:05 > 0:23:09- Flirt?- Yep. The males have a moving rippling
0:23:09 > 0:23:10colour running down their back.
0:23:10 > 0:23:13That's them trying to get the attention of the females
0:23:13 > 0:23:15and it definitely works. It's slightly hypnotic.
0:23:15 > 0:23:20Look into my eyes, or rather, look into my ripples!
0:23:20 > 0:23:23It looks like the females are saying "I see you baby!"
0:23:24 > 0:23:26Oh, yeah, and it works OK,
0:23:26 > 0:23:29as you can see, by the face-sucking going on!
0:23:29 > 0:23:33But I can't see how they're all linked to the Flashlight Fish?
0:23:33 > 0:23:35It's easy! They both use vision to communicate...
0:23:35 > 0:23:39the Cuttlefish through colour effects and the Flashlight Fish
0:23:39 > 0:23:41by flashing their little torches.
0:23:41 > 0:23:43Thanks for clearing that up. OK, next.
0:23:45 > 0:23:49Why, Mr Fish, what a big mouth you have!
0:23:49 > 0:23:53- He's called the Napoleon Wrasse, or the Humphead Wrasse.- Ah, he has got
0:23:53 > 0:23:57a hump-head! In fact, I couldn't have put it better myself!
0:23:57 > 0:23:59So what's so special about this geezer, apart from the fact
0:23:59 > 0:24:02he must have the biggest gob in the ocean!
0:24:02 > 0:24:04Well, he's another ocean flirt.
0:24:04 > 0:24:07He blushes when he fancies a female!
0:24:07 > 0:24:08Ah, so he has got a soft side?
0:24:08 > 0:24:11He doesn't look the romantic type!
0:24:11 > 0:24:15What's weird about these guys, or girl should I say,
0:24:15 > 0:24:17is that they all start out as females.
0:24:17 > 0:24:19Hey, how does that work?
0:24:19 > 0:24:22They all live under the protection of one male who
0:24:22 > 0:24:25looks after them all and then he chooses who he wants to mate with.
0:24:25 > 0:24:28- Lucky him!- And when the males want to flirt, their hump darkens.
0:24:28 > 0:24:32I suppose you could say they wear their heart on their hump!
0:24:32 > 0:24:37Well, I guess it's a different way of saying "I fancy you!"
0:24:37 > 0:24:39It's like the dazzling Cuttlefish,
0:24:39 > 0:24:40who also uses colour to get attention.
0:24:40 > 0:24:43So, our romantic but not-so-handsome Napoleon Wrasse
0:24:43 > 0:24:45is connected to the Cuttlefish
0:24:45 > 0:24:48as both like to flirt and communicate using colour-change.
0:24:48 > 0:24:50So, who's our next visual wonder?
0:24:53 > 0:24:55You don't often get the chance
0:24:55 > 0:24:57to use the phrase "I've got you stuck to my face".
0:24:57 > 0:25:00Gem, have you changed the show to make it all about romance?
0:25:00 > 0:25:04There's even more fish-flirting, or are they stuck together?
0:25:04 > 0:25:05Nothing to do with me!
0:25:05 > 0:25:08They are cute, though. I think they're dancing, cheek to cheek.
0:25:08 > 0:25:10Or, maybe the little one is too forward.
0:25:10 > 0:25:14The big one could be saying "here, back off, lass, give me some space".
0:25:14 > 0:25:16Well, they're flirting, actually.
0:25:16 > 0:25:18Not very subtle, is it?
0:25:18 > 0:25:22The reason they recognise each other though is because they change colour
0:25:22 > 0:25:25from babies, who are this colour, to females who end up looking like
0:25:25 > 0:25:28this, but even stranger, they all
0:25:28 > 0:25:33- change colour again when they're older and turn into a male!- What?
0:25:33 > 0:25:39So, the females change colour and then into men? Well, that's weird!
0:25:39 > 0:25:42I know! This is another example of how fish recognise each other.
0:25:42 > 0:25:45They know who to hook up a mate with and when to do it. Clever, eh?
0:25:45 > 0:25:47Colour-change links the Parrotfish back
0:25:47 > 0:25:49to our blushing Napoleon Wrasse.
0:25:49 > 0:25:51And this links us right back to our first contender...
0:25:51 > 0:25:52the Damsel Fish...
0:25:52 > 0:25:56who recognise each other through their ultraviolet markings
0:25:56 > 0:25:59which only they can see. What a cool collection of connections.
0:25:59 > 0:26:03- Let's see those again.- I agree!
0:26:06 > 0:26:07OK, first up, Damsel Fish and Crocodiles
0:26:07 > 0:26:10are connected because they both see better than humans.
0:26:10 > 0:26:12The Turtle was next a mini-connection,
0:26:12 > 0:26:15because they can see both above and below water, like the Croc.
0:26:15 > 0:26:19- But not as well on land. Your turn. - I need a clue.
0:26:21 > 0:26:24Ah, the Mudskipper with his 200 degree panoramic vision.
0:26:24 > 0:26:27Linked to our other super-sighted little guy, the Mantis Shrimp.
0:26:27 > 0:26:29Followed by the Pistol Shrimp, another mini connection.
0:26:29 > 0:26:32They can't see as well, but they have their mates,
0:26:32 > 0:26:34the Goby Fish, to give them a hand.
0:26:34 > 0:26:36- So, who's next? The Octopus?- Nope.
0:26:36 > 0:26:39- Another wobbly animal, though. - Ah, the Box Jelly, of course.
0:26:39 > 0:26:42Deadly, venomous and with 24 eyes!
0:26:42 > 0:26:45The next connection is the Octopus who talks by changing colour.
0:26:45 > 0:26:47And he is a Cephla...Cephalopod.
0:26:47 > 0:26:50Finally you got it! One of them!
0:26:50 > 0:26:53- Thank you!- Yeah! - The Nautilus is as old as the ocean
0:26:53 > 0:26:57but can still see in the dark through his pin-hole camera eye.
0:26:57 > 0:26:59And it's linked to the Clam, with its hundreds of basic eyes.
0:26:59 > 0:27:02A mini-connection, our night-hunter, the Shark,
0:27:02 > 0:27:04- can also see in the dark. - Like the Flashlight Fish.
0:27:04 > 0:27:07And they are connected to the Cuttlefish, as they both use
0:27:07 > 0:27:09flashy techniques to communicate.
0:27:09 > 0:27:11So, we are left with our two flirters...
0:27:11 > 0:27:14the Napoleon Wrasse, another colour communicator...
0:27:14 > 0:27:16And last, but not least, the smoochy Parrotfish.
0:27:16 > 0:27:19- They stick together in more ways than one!- Are these yours?
0:27:19 > 0:27:22- You found them! Cool! - Well, I've confiscated them.
0:27:22 > 0:27:24I mean fish might not see quite like
0:27:24 > 0:27:27we do, but with their super-sighted vision, I think they deserve better!
0:27:27 > 0:27:29But they're my favourites!
0:27:40 > 0:27:41Subtitles by Red Bee Media Ltd
0:27:41 > 0:27:43E-mail subtitling@bbc.co.uk