0:00:02 > 0:00:04Australia, home of the possum, surfers,
0:00:04 > 0:00:08strange lingo - "No worries mate, fair dinkum", and the Barrier Reef.
0:00:08 > 0:00:12It's the biggest, most spectacular coral reef in the world.
0:00:12 > 0:00:14And 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 > 0:00:25they're all connected in Barney's Barrier Reef.
0:00:46 > 0:00:48Ah, the Great Barrier Reef.
0:00:48 > 0:00:50I've got the sun, the sea.
0:00:50 > 0:00:55I'm surrounded by beautiful fish, coral and creatures. So peaceful.
0:00:55 > 0:00:59I think I'll have a bit of a snooze. Ah, yes.
0:01:06 > 0:01:10- What's going on?! What are you doing?- There's no time for snoozing.
0:01:10 > 0:01:14If I was a Barrier Reef hitman, you'd be in real trouble by now.
0:01:14 > 0:01:16OK, what's your point?
0:01:16 > 0:01:20Look, all the creatures out in the Reef may look cute and colourful
0:01:20 > 0:01:23but out there in the ocean, it's every fish for itself.
0:01:23 > 0:01:27There are dangerous hitmen round every watery corner,
0:01:27 > 0:01:33- so you have to be prepared.- Hitmen? Gem, fish aren't hitmen.
0:01:33 > 0:01:35Er, yes they are.
0:01:35 > 0:01:40- They're biters, spearers, and boxers.- OK, give me that.
0:01:40 > 0:01:44OK, it's time to face our scary predators.
0:01:44 > 0:01:47Hitmen, armed and dangerous.
0:01:59 > 0:02:04- Introducing our first ocean hitman, the tiger shark.- Bonjour.
0:02:04 > 0:02:06Sleek, shiny and stealthy.
0:02:06 > 0:02:09Heavyweight of the sea and granddaddy of the ocean.
0:02:09 > 0:02:14You can see why they've been around for more than 400 million years.
0:02:14 > 0:02:17400 million years? He looks good on it, if a little scary.
0:02:17 > 0:02:22He doesn't even have to try. He was born a predator and he knows it.
0:02:22 > 0:02:24He doesn't look much like a tiger.
0:02:24 > 0:02:27He's called the tiger shark because of his side stripes.
0:02:27 > 0:02:31The largest one found was over 7 metres long.
0:02:31 > 0:02:33Hang on a minute -
0:02:33 > 0:02:37that's the length of three-and a-half Peter Crouches.
0:02:41 > 0:02:44Is that a rotting turtle that he's eating? Gross!
0:02:44 > 0:02:47Yeah, and he's got pretty filthy eating habits.
0:02:47 > 0:02:51They call him the garbage man of the sea cos he'll eat anything.
0:02:51 > 0:02:54This rotting, stinking turtle is perfect for him.
0:02:54 > 0:02:58Who else has the jaws to crunch through a turtle shell?
0:02:58 > 0:03:02Apparently, they've found all sorts in this garbage guts.
0:03:02 > 0:03:06Licence plates, tyres, bottles, tin cans, tennis shoes,
0:03:06 > 0:03:08plastic bags, a human head.
0:03:08 > 0:03:11- A human head? What?!- Ha-ha-ha!
0:03:11 > 0:03:16Yep, you name it, it's been found in a tiger shark's belly.
0:03:16 > 0:03:19In our interconnected Barrier Reef family,
0:03:19 > 0:03:24who's connected to this greedy guts? Enter our next hitman.
0:03:27 > 0:03:29SOUND OF ELECTRIC SAW
0:03:29 > 0:03:32- Excuse me.- Yo, wassup?
0:03:32 > 0:03:33Help!
0:03:33 > 0:03:38He's a flat-faced prowler, skulking around the forest of night.
0:03:38 > 0:03:41- Meet the sawfish. - What's for dinner?
0:03:41 > 0:03:45Whoah, look at that snout! You can see where he gets his name.
0:03:45 > 0:03:47He can't need that many teeth, surely?
0:03:47 > 0:03:50He uses his serrated snout like a metal detector.
0:03:50 > 0:03:54Well, more like a metal detector, vacuum cleaner and baseball bat
0:03:54 > 0:03:55rolled into one.
0:03:55 > 0:03:57He's the ocean slasher.
0:03:57 > 0:04:01The electro-sensory pores in his saw snout can detect movement
0:04:01 > 0:04:04and heartbeats from a distance.
0:04:04 > 0:04:07- One slash is all it takes to bring the victim down.- G'day, mate.
0:04:07 > 0:04:12Or he simply uses his suction snout to swallow his victim whole.
0:04:12 > 0:04:13Impressive stuff.
0:04:13 > 0:04:15- Ha-ha-ha!- Oh-oh!
0:04:15 > 0:04:19So, the sawfish attacks by shaking its toothy snout,
0:04:19 > 0:04:22and the tiger shark shakes its entire body to tear off food.
0:04:22 > 0:04:26Our slashing shaker, the sawfish, is connected to our tearing shaker,
0:04:26 > 0:04:29the tiger shark, because they're both shaking hitmen.
0:04:31 > 0:04:37Aw, what a pretty shell! I'm sure I've seen these on Blackpool Beach.
0:04:37 > 0:04:40He's not a great mover, is he? In your own time, love.
0:04:40 > 0:04:43Well, he may look sweet and innocent, but he's not.
0:04:43 > 0:04:46He's a true sea stalker.
0:04:46 > 0:04:49He hunts at night. Silent but deadly,
0:04:49 > 0:04:52- he creeps along the ocean floor, until...- I'm gonna get you!
0:04:54 > 0:04:57Well, until it's too late.
0:04:59 > 0:05:02Yeah, maybe you don't get them in Blackpool after all.
0:05:02 > 0:05:06Did you see his tongue? On the end, there's at tooth.
0:05:06 > 0:05:09But not just any ordinary tooth,
0:05:09 > 0:05:13a barbed tooth that stabs its prey like a poisoned dart.
0:05:13 > 0:05:15The speed of attack and his deadly venom
0:05:15 > 0:05:20mean he's not someone you'd want to cross or make cross.
0:05:20 > 0:05:22Am I missing something, here?
0:05:22 > 0:05:25- Deadly venom? But it's a snail?- I know, but he has
0:05:25 > 0:05:30one of the most deadly venoms in the ocean, capable of killing people.
0:05:33 > 0:05:35Yep, that's pretty deadly.
0:05:35 > 0:05:39And he can start digesting his food before his prey have even died.
0:05:39 > 0:05:42You mean he's chewing them and killing them at the same time?
0:05:42 > 0:05:45All this from something that's basically a sea snail.
0:05:45 > 0:05:48So, what do you think connects this shell to the sawfish?
0:05:48 > 0:05:53The sawfish has hundreds of teeth on the outside, but the cone shell
0:05:53 > 0:05:58- has just one deadly spearing tooth. The connection is teeth.- Of course.
0:06:03 > 0:06:08This is how the most venomous animal in the world kills its victims.
0:06:08 > 0:06:11Spring-loaded stingers in the tentacles shoot
0:06:11 > 0:06:16through the skin and inject deadly toxins into the blood vessels.
0:06:16 > 0:06:18But he's just a jellyfish!
0:06:18 > 0:06:22He's silent, ghostly and pale.
0:06:22 > 0:06:25Apparently, these guys are so hard to see that for years,
0:06:25 > 0:06:27no-one even knew they existed.
0:06:27 > 0:06:31Who'd have thought a creature made almost entirely of water
0:06:31 > 0:06:34would turn out to be the deadliest animal on the planet?
0:06:34 > 0:06:36An invisible hitman?
0:06:36 > 0:06:40- Now that is scary.- What's more, their prey have no chance.
0:06:40 > 0:06:42The box jelly has 60 tentacles,
0:06:42 > 0:06:45five thousand million stinging barbs,
0:06:45 > 0:06:49can be up to four metres long and has 24 eyes.
0:06:49 > 0:06:52People think they drift, but they actually swim with jet-like
0:06:52 > 0:06:57propulsion and travel at a speed of 1.8 metres every second.
0:06:57 > 0:07:00That's as quick as we can walk, not bad for something with no legs.
0:07:03 > 0:07:07And they prefer shallow waters, just like paddlers and swimmers,
0:07:07 > 0:07:12which is why they've killed more people than the Great White Shark.
0:07:12 > 0:07:17Remind me to paddle in full protection next time.
0:07:17 > 0:07:19Are these box jellyfish common?
0:07:19 > 0:07:23No, not massively. They only exist in tropical waters,
0:07:23 > 0:07:26so you won't bump into one in the UK or Europe this summer.
0:07:26 > 0:07:31On a lighter note, they apparently have the 64 bottoms.
0:07:31 > 0:07:36- Just as well they don't eat beans. - 64 bottoms? Don't they get confused?
0:07:36 > 0:07:39The cone shell had deadly venom, too, like the box jellyfish.
0:07:39 > 0:07:44Yes, the box jelly and cone shell are very definitely venomous hitmen.
0:07:44 > 0:07:48So the connection between the box jelly and the cone shell is venom.
0:07:48 > 0:07:53So which hitman is linked to our silent but deadly box jelly?
0:07:56 > 0:07:59I like these. Some of the best lookers in the ocean.
0:07:59 > 0:08:04Bright, colourful and graceful, like pretty flowers blowing in the breeze.
0:08:04 > 0:08:07Don't be fooled, Gem, these aren't flowers.
0:08:07 > 0:08:10- They're anemones.- I'm scared!
0:08:10 > 0:08:12Living animals who set up camp on coral and rock,
0:08:12 > 0:08:15and some anemones are best kept at arm's length.
0:08:15 > 0:08:19I don't believe you. Anemones aren't dangerous, they're lovely.
0:08:19 > 0:08:25But this is an extreme anemone. You wouldn't want to sniff this flower.
0:08:25 > 0:08:27Its tentacles are filled with venom.
0:08:27 > 0:08:30One sniff and the victim is a goner.
0:08:30 > 0:08:33- No way. How? - Well, these buttons hardly move.
0:08:33 > 0:08:35They don't have to.
0:08:35 > 0:08:39They stop fish in their tracks with their pretty but deadly tentacles.
0:08:39 > 0:08:43Now you see it, now you don't.
0:08:43 > 0:08:45The fish gets swallowed whole.
0:08:45 > 0:08:47And there's more.
0:08:47 > 0:08:50An anemone's mouth doubles up as its bottom.
0:08:50 > 0:08:53So, they eat their prey whole through their hole?
0:08:53 > 0:08:55Whole through their hole, get it?
0:08:55 > 0:08:58They are some of the weirdest venomous creatures ever.
0:08:58 > 0:09:02One minute as pretty as a picture, the next, Jabba the Hut.
0:09:02 > 0:09:03Ha-ha-ha!
0:09:03 > 0:09:07So they have a vicious venom cocktail
0:09:07 > 0:09:10- just like the invisible box jellyfish?- Ah-ha! Of course.
0:09:10 > 0:09:15The anemone and deadly box jellyfish are connected by venom.
0:09:18 > 0:09:21- A crab? Surely he's not that dangerous?- Not really,
0:09:21 > 0:09:24but this crafty dude is a little different.
0:09:24 > 0:09:28Hang on a minute, what's he got on his hands, I mean pincers?
0:09:28 > 0:09:31The boxer crab hasn't got his own stinging cells
0:09:31 > 0:09:34so he has to nick them. Pretty cheeky, eh?
0:09:34 > 0:09:37He borrows little anemones to ward off predators.
0:09:37 > 0:09:40It's a mutualistic friendship - there are many in the Reef.
0:09:40 > 0:09:43Animals form a mutually beneficial relationship -
0:09:43 > 0:09:46they support each other to help them both survive.
0:09:46 > 0:09:50So, basically, you scratch my back and I'll scratch yours?
0:09:50 > 0:09:54Yep, and in this case, the crab gets to ward off predators
0:09:54 > 0:09:57but he also uses his flowery hands to mop up leftovers,
0:09:57 > 0:10:00so the anemone gets to eat as well.
0:10:00 > 0:10:02So he's a bit of a geezer hitman -
0:10:02 > 0:10:05ducking and diving to keep away enemies with his anemones.
0:10:05 > 0:10:07Clever, or what?
0:10:07 > 0:10:10Yes, but do you think he knows how ridiculous he looks?
0:10:10 > 0:10:12He looks a bit like a cheerleader crab.
0:10:12 > 0:10:16"Give me a C, give me an R, give me an A, give me a B!
0:10:16 > 0:10:18"What do you get? Crab!"
0:10:18 > 0:10:20Oh, yes. More!
0:10:20 > 0:10:25So, you see, the harmless boxer crab uses our venomous anemone
0:10:25 > 0:10:27to turn itself into a bit of a hitman.
0:10:27 > 0:10:31OK, I get it. Basically, our boxer crab and anemone are connected
0:10:31 > 0:10:34as he pinches the anemone's sting with his pinching pincers.
0:10:37 > 0:10:39Hey, amigos.
0:10:39 > 0:10:42Look at him cleaning out his hole.
0:10:42 > 0:10:47This shrimp is very house-proud. At first glance, a real cutie...
0:10:47 > 0:10:51- if a little alien like.- It's called the mantis shrimp because
0:10:51 > 0:10:54he looks a bit like a praying mantis.
0:10:54 > 0:10:56He's got quite a few nicknames.
0:10:56 > 0:11:00He's been called a sea grasshopper, prawn killer, thumb splitter...
0:11:00 > 0:11:03Thumb splitter? That doesn't sound sweet and innocent.
0:11:06 > 0:11:08Are you talking about human thumbs?
0:11:10 > 0:11:14Mr Mantis Shrimp clubs his victims to death with a punch
0:11:14 > 0:11:16as fast as a 22 calibre bullet.
0:11:18 > 0:11:19Not bad for shrimp!
0:11:22 > 0:11:24In the red corner, we have Super Shrimp.
0:11:24 > 0:11:29In the blue corner, we have Courageous Crab.
0:11:29 > 0:11:32Shrimp gets in there, but Courageous is braver than he looks.
0:11:32 > 0:11:35Good left hook, Courageous. Round one to Courageous Crab.
0:11:38 > 0:11:42Super Shrimp delivers a painful blow, Crab hanging on in there.
0:11:42 > 0:11:44What stamina this young fellow has!
0:11:46 > 0:11:51Oh, it's all over. Courageous Crab has had enough of this onslaught.
0:11:51 > 0:11:54Shrimp is left with the prize, the crab's pincer.
0:11:57 > 0:12:00As well as a punch as fast as a speeding bullet,
0:12:00 > 0:12:03he also has awesome eyesight.
0:12:03 > 0:12:04Each eye has the three pupils
0:12:04 > 0:12:08and he can see colour more than three times better than we can.
0:12:08 > 0:12:11Three pupils and three times better colour vision than us?
0:12:11 > 0:12:14I guess it might be like watching HDTV in 3D vision?
0:12:14 > 0:12:17Something like that. He's got strength, agility,
0:12:17 > 0:12:21speed and vision and can attack prey much bigger than he is.
0:12:21 > 0:12:26He's the Amir Khan of the sea world. Small but deadly, a true mini hitman.
0:12:27 > 0:12:30Another boxing hitman, which connects him to the boxer crab
0:12:30 > 0:12:32with his stinging boxing gloves.
0:12:32 > 0:12:35Exactly, Mr Mantis Shrimp packs a punch
0:12:35 > 0:12:37which links him to the bonkers boxer crab.
0:12:39 > 0:12:42Wow, you're right, they are a scary bunch.
0:12:42 > 0:12:44I'm not sure I want to be reminded.
0:12:44 > 0:12:47Too bad, because it's time for a Reef-cap.
0:12:51 > 0:12:56How did we get from our tiger shark all the way to our mantis shrimp
0:12:56 > 0:12:57in our hitmen line-up?
0:12:57 > 0:13:00The tiger shark's shake is linked to the sawfish,
0:13:00 > 0:13:03who slashes and shakes with his toothy snout.
0:13:03 > 0:13:05His weapon of choice is teeth,
0:13:05 > 0:13:08along with the cone shell with his deadly spearing tooth.
0:13:08 > 0:13:12Lethal venom links him to our ghostly but deadly box jellyfish.
0:13:12 > 0:13:14They look like pretty flowers,
0:13:14 > 0:13:19but don't sniff the anemone, they have deadly stinging tentacles.
0:13:19 > 0:13:21Which Mr Boxer Crab nicks and puts on his pincers
0:13:21 > 0:13:24to make himself a ready-made hitman.
0:13:24 > 0:13:26Just a shame he ends up looking like a cheerleader.
0:13:26 > 0:13:30His stinging right hook links him to our other punching hitman,
0:13:30 > 0:13:32the mantis shrimp.
0:13:32 > 0:13:34- Whatever next? - You haven't seen anything yet.
0:13:34 > 0:13:38Get yourself ready for one of the deadliest hitmen in the ocean.
0:13:38 > 0:13:41- Take this.- What? A water pistol?
0:13:41 > 0:13:44What good's a water pistol against a tiger shark?
0:13:44 > 0:13:45Gem, don't leave me!
0:13:55 > 0:13:59- So, who's this, then? - A blue-ringed octopus.
0:13:59 > 0:14:03He's a bit of a looker! One of the better looking octopuses I've seen.
0:14:03 > 0:14:07Not that I think a lot about how good-looking octopuses are.
0:14:07 > 0:14:10Hold on, did he just change colour? Play that again.
0:14:10 > 0:14:14Yep, and he looks prettier when he's angry.
0:14:14 > 0:14:18When he's threatened, flashing blue spots appear all over his body.
0:14:20 > 0:14:23I have a feeling that crab may not have long to live.
0:14:23 > 0:14:25Yep, he's on the hunt.
0:14:25 > 0:14:28See, I knew that crab wouldn't make it through this sequence.
0:14:28 > 0:14:32And now he's got him, it's time to spew his deadly venom.
0:14:32 > 0:14:35Despite being the size of a tennis ball,
0:14:35 > 0:14:40- he has enough venom to kill 26 humans within minutes.- Hang on.
0:14:49 > 0:14:51You said that so casually, Gem.
0:14:51 > 0:14:56Did you just say enough venom to kill 26 humans? That's impossible.
0:14:56 > 0:14:59Not when he has another trick up his eight sleeves.
0:14:59 > 0:15:02You've seen him squirt, but then there's also the bite.
0:15:02 > 0:15:04Octopuses do not have teeth!
0:15:04 > 0:15:07Worse than that, he's got a razor-sharp beak.
0:15:07 > 0:15:11- Of course he has!- He delivers his toxic saliva to paralyse the pray
0:15:11 > 0:15:14so he doesn't get hurt by the crab's pincers,
0:15:14 > 0:15:18and he can bring down and paralyse a human just as quickly.
0:15:18 > 0:15:20So what on earth connects the shrimp and octopus?
0:15:20 > 0:15:24They both have an obsession with destroying crabs.
0:15:24 > 0:15:30- Obviously.- He swims like an eel, but looks like a snake.
0:15:30 > 0:15:31What's going on here?
0:15:31 > 0:15:34He's a sea snake, just like his relatives the land snakes,
0:15:34 > 0:15:39- but with a paddle as a tail.- That's evolution for you. Pretty cool, eh?
0:15:39 > 0:15:42It looks like this one is sunbathing.
0:15:42 > 0:15:45No, he's just come up for a breath of fresh air.
0:15:45 > 0:15:49They live in the water but they're reptiles, and so instead of gills,
0:15:49 > 0:15:53they have a lung and need to come up regularly to the surface to breathe.
0:15:53 > 0:15:57When they're running low, they can also obtain oxygen from their skin,
0:15:57 > 0:16:01particularly their bottom where the skin is thin.
0:16:01 > 0:16:04Breathing through your bottom! I like it.
0:16:04 > 0:16:06So why does he qualify as a hitman?
0:16:06 > 0:16:11Not all snakes are dangerous, and he looks quite friendly.
0:16:11 > 0:16:14Oh no, he's actually highly venomous.
0:16:14 > 0:16:18- What?!- He may only inject a little bit of venom,
0:16:18 > 0:16:20but it's very, very strong stuff.
0:16:20 > 0:16:22But he's a selective hitman.
0:16:22 > 0:16:26He only uses his venom when he's really angry, and will often
0:16:26 > 0:16:29give a non-venomous little bite first to warn off his predators.
0:16:29 > 0:16:32And they love to look in nooks and crannies for their prey?
0:16:32 > 0:16:36Yep, and they're the perfect shape for squeezing into tight spaces,
0:16:36 > 0:16:42but snakes have bad eyesight so they smell for their prey instead.
0:16:42 > 0:16:46- Oh no!- He's pinned him against the wall, that's cheating!
0:16:46 > 0:16:49When they find their victim, they don't waste any time.
0:16:49 > 0:16:53He bites, delivers the venom and then, it's lunchtime.
0:16:55 > 0:16:57I don't know what's worse,
0:16:57 > 0:17:01being bitten by a sea snake or by a razor-sharp octopus beak.
0:17:01 > 0:17:04Our slinky sea snake and blue-ringed octopus
0:17:04 > 0:17:06are both venomous biters.
0:17:10 > 0:17:13Next up, the white tip reef shark.
0:17:13 > 0:17:16- What? More sharks?- Yep. On the Barrier Reef, there are
0:17:16 > 0:17:21125 species in the shark family, and none of them are the same.
0:17:21 > 0:17:23The white tip reef sharks are strong,
0:17:23 > 0:17:27- agile and some of the hungriest hunters.- What makes them different?
0:17:27 > 0:17:28All sharks can hunt.
0:17:28 > 0:17:33Yeah, all sharks can hunt, but white tips treat hunting as a team sport.
0:17:37 > 0:17:41By day, they're hidden. But once night falls, the action begins.
0:17:41 > 0:17:44They hunt together in gangs of three or four.
0:17:44 > 0:17:47- OK, they're like the gangsters of the Reef?- Yeah.
0:17:47 > 0:17:50Prey can hide all they want but they have a hidden talent
0:17:50 > 0:17:53which allows them to get into smaller crevices.
0:17:53 > 0:17:55White tips have indestructible skin.
0:17:55 > 0:17:59Coral don't look too bad, but they are razor-sharp.
0:17:59 > 0:18:03They would slice our skin open like a cheese grater.
0:18:03 > 0:18:06- But not the white tips.- Super skin. That is awesome.
0:18:06 > 0:18:10Once they have their loot, they don't share it, do they?
0:18:10 > 0:18:14Now he's got the fish, he's decided it's every shark for himself.
0:18:14 > 0:18:18Combine this with a super sense of smell, hearing and electro-sense,
0:18:18 > 0:18:23if you're on this gang's menu, you won't make it through the night.
0:18:23 > 0:18:27So, like most gangs, do they tend to stay in the 'hood, homey?
0:18:27 > 0:18:30Unlike some other sharks, they aren't big travellers.
0:18:30 > 0:18:33They don't like leaving their pack.
0:18:33 > 0:18:36So they get homesick? That's sweet, kind of.
0:18:36 > 0:18:38Glad you like this dangerous hunter.
0:18:38 > 0:18:41Did you think our hunting sea snake was cute as well?
0:18:41 > 0:18:43Maybe sweet was the wrong word.
0:18:43 > 0:18:45Anyway, the white tip reef sharks
0:18:45 > 0:18:48with their gang hunts and indestructible skin
0:18:48 > 0:18:51are connected to the shifty sea snake by hunting.
0:18:51 > 0:18:53Deadly snakes, boxer shrimps.
0:18:53 > 0:18:56Whatever next? It's time for a Reef-cap.
0:19:02 > 0:19:05How did we get from the mantis shrimp to the sea snake?
0:19:06 > 0:19:10Our hitman shrimp is connected to the blue-ringed octopus because
0:19:10 > 0:19:13they share an obsession for destroying crabs.
0:19:13 > 0:19:14Bit of a random link.
0:19:14 > 0:19:18Random, but very true. The scary, flashing blue-ringed octopus
0:19:18 > 0:19:22is connected to the sea snake by their deadly venomous bites.
0:19:22 > 0:19:27And the sea snake hunts for prey in nooks and crevices.
0:19:27 > 0:19:30Who on earth are left? There can't be many more hitmen in the ocean?
0:19:30 > 0:19:33Who's connected to the white tips?
0:19:33 > 0:19:37- It must be some big, deadly, scary, venomous creature, surely?- Not quite.
0:19:37 > 0:19:40In fact, he's right in front of you.
0:19:40 > 0:19:45MANIC LAUGHTER PLAYS ON SOUNDTRACK
0:19:56 > 0:19:58What am I looking at?
0:19:58 > 0:20:00- Er, cue hitman, please!- He's there.
0:20:00 > 0:20:03Well, what's this? The invisible hitman?
0:20:03 > 0:20:05I'm looking and there's just some coral,
0:20:05 > 0:20:09there's starfish, and that plankton-type stuff...
0:20:09 > 0:20:13Our next hitman is the starfish, or sea star as the Aussies call them.
0:20:13 > 0:20:14OK, this one I don't believe.
0:20:14 > 0:20:18Starfish have to be the most harmless sea thing going.
0:20:18 > 0:20:22They look like they should be on a Wish You Were Here postcard.
0:20:24 > 0:20:26Dude, you are, like, so wrong.
0:20:26 > 0:20:29They hunt in enormous numbers.
0:20:29 > 0:20:32Once they're fully grown, they go on the rampage, eating coral.
0:20:32 > 0:20:36There's no way a sea starfish can go on any rampage.
0:20:36 > 0:20:38I mean, can they even walk?
0:20:38 > 0:20:41Yeah, they've got more than 20 legs, and thousands of feet.
0:20:41 > 0:20:4620 legs?! But I thought they only had five. Er, like a star?
0:20:46 > 0:20:48No, you're thinking of those English stars.
0:20:48 > 0:20:53Barrier Reef sea stars are a whole different ball game.
0:20:53 > 0:20:56What's more, they've no brain but can still coordinate all
0:20:56 > 0:20:5920 legs to walk in one direction.
0:20:59 > 0:21:03Amazing! They still look too harmless to be a predator, though?
0:21:03 > 0:21:06Well, looks can be deceiving. They may look sweet and innocent,
0:21:06 > 0:21:10but sea stars are covered in a toxic gel that really stings.
0:21:10 > 0:21:12Not to mention the spikes. Ouch.
0:21:12 > 0:21:16They chomp their way through whole colonies of coral,
0:21:16 > 0:21:20leaving just a ghostly white trail of destruction.
0:21:20 > 0:21:23They eat in a huge army, devouring everything in sight.
0:21:23 > 0:21:27Are you for real? That's so super sci-fi.
0:21:27 > 0:21:32So it's another gang of hitmen, just like the white tip reef sharks?
0:21:32 > 0:21:37Our spooky sci-fi crown of thorns is connected to our white tip gangs
0:21:37 > 0:21:39because they hunt in gangs.
0:21:42 > 0:21:45Onto one of the reef's most common and colourful characters.
0:21:45 > 0:21:48Hang on, hang on, hang on.
0:21:48 > 0:21:51Look, this show is supposed to be about hitmen,
0:21:51 > 0:21:53not pretty, harmless fish.
0:21:53 > 0:21:55They don't scare me.
0:21:55 > 0:21:57They've no venom, no stinging tentacles,
0:21:57 > 0:22:00no claw that can punch like a heavyweight.
0:22:00 > 0:22:03You still haven't learnt looks can be deceptive.
0:22:03 > 0:22:05Well, welcome to the Barrier Reef.
0:22:05 > 0:22:09Creatures that look cute can often be dangerous predators.
0:22:09 > 0:22:12I thought you'd have picked up on that by now.
0:22:12 > 0:22:15Well, come on, then. Sock it to me.
0:22:15 > 0:22:19Firstly, why do you think he's called a parrot fish?
0:22:19 > 0:22:23Because he's pretty and carries a mirror with him that he head-butts?
0:22:23 > 0:22:27Wrong. It's because he has not one but two deadly sets of
0:22:27 > 0:22:31jaws and teeth which they use to demolish their prey.
0:22:31 > 0:22:33So their mouth looks like a parrots' mouth.
0:22:33 > 0:22:36They've got the teeth of rabbits.
0:22:36 > 0:22:39They should be called parrot-rabbit-fish!
0:22:39 > 0:22:42What harm can they do? They're just fish?
0:22:42 > 0:22:46Well, they may not qualify as a hitman, but more as hitmen.
0:22:46 > 0:22:50These guys graze and graze and graze on algae,
0:22:50 > 0:22:53which they scrape off rocks and coral.
0:22:53 > 0:22:57They have rock-hard teeth so they can pulverise the bits of rock.
0:22:57 > 0:23:00Sorry, still don't buy it. They're not hitmen.
0:23:00 > 0:23:04Let me finish. The thing is, the parrot fish are greedy.
0:23:04 > 0:23:09They need more and more algae, and to get the algae, they play dirty.
0:23:11 > 0:23:16Take this area of the Reef, the home of the cute and gentle damsel fish.
0:23:16 > 0:23:19The parrot fish decide they want peace of the action,
0:23:19 > 0:23:24so they enlist the help of their mates by forming a huge, big gang
0:23:24 > 0:23:26who then bully the damsel fish out of their home
0:23:26 > 0:23:31and feed on their nice, lush algae, leaving a pretty empty area.
0:23:31 > 0:23:34So they're like gang hitmen? Not scary on their own,
0:23:34 > 0:23:37but when they're with their mates, they turn nasty.
0:23:37 > 0:23:42So, not as innocent as he looks, the parrot fish
0:23:42 > 0:23:46and his chomping posse are connected to the crown of thorns sea star
0:23:46 > 0:23:48because they both gang up on coral.
0:23:50 > 0:23:54SNORING Hey, wake up! That's better.
0:23:54 > 0:23:57He's a true Aussie hitman, this one.
0:23:57 > 0:23:59And probably the most deadly of all.
0:23:59 > 0:24:03The Australian salt water croc, or salties, as the Aussies call them.
0:24:03 > 0:24:07- Look at his skin! It looks prehistoric.- Well, he practically is.
0:24:07 > 0:24:11Salties have been around for more than 200 million years.
0:24:11 > 0:24:13No wonder he looks a bit worn out.
0:24:13 > 0:24:17I hear they've got quite a reputation in Australia?
0:24:17 > 0:24:20Yeah, they're admired and feared at the same time,
0:24:20 > 0:24:24especially in Oz, and the big ones can weigh up to 1,000 kilograms.
0:24:24 > 0:24:28Hang on, that's the same as 15 people!
0:24:28 > 0:24:31Yep, and they're masters of camouflage.
0:24:31 > 0:24:35They lurk in the water, staying as still as a rock or branch
0:24:35 > 0:24:38until they spot their prey.
0:24:38 > 0:24:42- Oh! Bye-bye, cute animal. - That was a wallaby.
0:24:42 > 0:24:44You're right there, it WAS a wallaby.
0:24:44 > 0:24:47The croc's most deadly attack is the death roll,
0:24:47 > 0:24:50where he grabs his prey and rolls it powerfully under the water.
0:24:50 > 0:24:54They eat pretty much everything, including buffalo, wallabies,
0:24:54 > 0:24:58other reptiles, birds, sharks and humans.
0:24:58 > 0:25:01Remind me not to go paddling in the croc creeks.
0:25:01 > 0:25:05They don't really have a taste for humans, but they can be aggressive.
0:25:05 > 0:25:09One croc hassled a fishermen so much he had to be locked up in a cell.
0:25:09 > 0:25:11No way! Croc criminals!
0:25:11 > 0:25:14His jaw is much bigger than the parrot fish's beak,
0:25:14 > 0:25:18but they're both mega toughies in the mouth department.
0:25:18 > 0:25:22Crocodiles are connected to parrot fish by their super-strong jaws.
0:25:22 > 0:25:26They also shake their prey, which connects them to the tiger shark.
0:25:26 > 0:25:28I wonder who'd win in that face off?
0:25:28 > 0:25:30Are you sure it's safe to come out?
0:25:30 > 0:25:33Yes, I've checked and double-checked the area.
0:25:33 > 0:25:37There are no signs of shrimps, octopuses or jellyfish anywhere.
0:25:37 > 0:25:40- Come on, Barney. Let's get on with the Reef-cap.- OK.
0:25:47 > 0:25:50I think we need to go over those connections again.
0:25:51 > 0:25:56The tiger shark is linked to the slashing, shaking sawfish.
0:25:56 > 0:26:00With his deadly sawing teeth, he's also connected to our sea stalker,
0:26:00 > 0:26:03the cone shell with its deadly toothy spear.
0:26:03 > 0:26:07Who would guess that something so innocent contains so much venom?
0:26:07 > 0:26:09Which linked him to the deadly box jelly,
0:26:09 > 0:26:13with his five thousand million stinging cells.
0:26:13 > 0:26:17Our flowery anemone is also venomous, but not that scary.
0:26:17 > 0:26:21How can you be scared of something that has a mouth that's a bottom?!
0:26:21 > 0:26:25- You wouldn't say that if you were that blue fish.- Probably not.
0:26:25 > 0:26:29Anyway, the anemone is linked to the cheerleading boxer crab.
0:26:29 > 0:26:31On his own, he's not so deadly,
0:26:31 > 0:26:34but he borrows the anemone's stinging tentacles.
0:26:34 > 0:26:39The boxer crab shares punching pincers with the mantis shrimp,
0:26:39 > 0:26:42whose knockout right hook makes him tiny but deadly.
0:26:42 > 0:26:46Especially to crabs. That links him to our venomous blue-ringed octopus.
0:26:46 > 0:26:50Don't forget his deadly bite, which connects him to the sea snakes.
0:26:50 > 0:26:53They can hunt down prey in any hole or corner,
0:26:53 > 0:26:56which links them to the white tip reef sharks,
0:26:56 > 0:27:00- whose super skin helps them find their dinner.- They hunt in packs,
0:27:00 > 0:27:03which ties them to our crown of thorn see stars who look harmless
0:27:03 > 0:27:07their own, but in their starry army, they destroy any coral in their path.
0:27:07 > 0:27:11Like the parrot fish, a scary gang of rock chompers who force
0:27:11 > 0:27:14other reef creatures out of their homes.
0:27:14 > 0:27:17Their super-strong jaws connect them to our fearsome croc,
0:27:17 > 0:27:19the hitman that legends are made of.
0:27:19 > 0:27:25Its weapon of choice is shaking, leading us back to the tiger shark.
0:27:25 > 0:27:29Phew, what a line-up. There are some dangerous hitmen in there.
0:27:29 > 0:27:31You know what, I think we're safe now.
0:27:31 > 0:27:34We can put all our protective gear away.
0:27:34 > 0:27:37Are you sure? You never know when you might need it.
0:27:37 > 0:27:39Who's going to get us now?
0:27:39 > 0:27:41It's the end of the show.
0:27:41 > 0:27:43MANIC LAUGHTER ECHOES
0:27:43 > 0:27:46- You can stop the scary laugh now, Barney.- Um, Gem...
0:27:46 > 0:27:48that's not me.
0:27:49 > 0:27:51MANIC LAUGHTER
0:28:07 > 0:28:09Subtitles by Red Bee Media Ltd
0:28:09 > 0:28:12E-mail subtitling@bbc.co.uk