0:00:00 > 0:00:00Here's Backshall's Best Bites. There he is - you've just seen him.
0:00:00 > 0:00:00I won.It's intense, isn't it?
0:00:02 > 0:00:04My name's Steve Backshall.
0:00:04 > 0:00:06Self-confessed shark-obsessed.
0:00:06 > 0:00:10This is one of the most awesome creatures in the sea.
0:00:10 > 0:00:13With over 500 species of sharks in our oceans,
0:00:13 > 0:00:15they range from the super speedy
0:00:15 > 0:00:17to the superpowered.
0:00:17 > 0:00:18The sensitive,
0:00:18 > 0:00:20to the sinister.
0:00:20 > 0:00:24Wow! And with millions of years of evolution behind them,
0:00:24 > 0:00:26they've evolved to be some of the most fascinating animals
0:00:26 > 0:00:27on our planet.
0:00:29 > 0:00:32This is one of the greatest things I've ever seen.
0:00:32 > 0:00:35There is so much more to sharks than first meets the eye.
0:00:36 > 0:00:39So I'm getting under their skin to reveal their
0:00:39 > 0:00:40startling inner secrets.
0:00:43 > 0:00:46This is Shark Bites,
0:00:46 > 0:00:49and these are my top ten favourite sharks.
0:00:51 > 0:00:55Kicking things off and speeding in at ten is a shark with
0:00:55 > 0:00:58some meteoric moves - the mako shark.
0:00:59 > 0:01:03It's on my list because this toothy torpedo can clock speeds of
0:01:03 > 0:01:0750km an hour, making it the fastest shark on the planet.
0:01:09 > 0:01:13I got a closer look at these lightning-quick sharks off the coast
0:01:13 > 0:01:16of San Diego on California's Pacific coast.
0:01:18 > 0:01:21As an idea of how fast they can go, right now,
0:01:21 > 0:01:26our boat's doing about 35km an hour, while a mako does 50 and
0:01:26 > 0:01:29could cruise straight past us as if we were standing still.
0:01:32 > 0:01:35Which makes them incredibly difficult to pin down.
0:01:37 > 0:01:39I think we might have something.
0:01:39 > 0:01:42Just a fin came up alongside the bait
0:01:42 > 0:01:45so that you didn't see it clearly enough to say even that
0:01:45 > 0:01:47it was a shark, let alone that it was a mako.
0:01:47 > 0:01:49There was only one way to find out.
0:01:50 > 0:01:53Mako shark. Coming right at him, coming right at him.
0:01:55 > 0:01:59The two of them are patrolling around us. One second they're there,
0:01:59 > 0:02:01the next second, they're gone.
0:02:01 > 0:02:03They just disappear into the blue.
0:02:03 > 0:02:05As the pair of them circle around me,
0:02:05 > 0:02:08I'm completely blown away by the ease at which they explode...
0:02:09 > 0:02:11..into these serious speeds.
0:02:11 > 0:02:13I don't think I've ever seen anything like it.
0:02:13 > 0:02:15It just always looks like it's on edge,
0:02:15 > 0:02:18always looks like it's ready to burst out into speed.
0:02:18 > 0:02:21So what is their surprising speed secret?
0:02:23 > 0:02:28Not only are these sharks superbly streamlined, with their cylindrical
0:02:28 > 0:02:31shape tapering at both ends, the tail's crescent-shaped,
0:02:31 > 0:02:33perfect for propulsion,
0:02:33 > 0:02:36and the short fins help reduce drag.
0:02:36 > 0:02:40But it's inside this shark that the magic really happens.
0:02:40 > 0:02:44Most sharks are ectothermic - that means cold-blooded.
0:02:44 > 0:02:48The temperature of their blood is the same as the water around them.
0:02:48 > 0:02:51But mako sharks are endothermic -
0:02:51 > 0:02:54they can generate their own heat from within.
0:02:54 > 0:02:58The warmth created in their muscles by activities like swimming and
0:02:58 > 0:03:02digesting their food can be retained in vital areas like the eyes,
0:03:02 > 0:03:06the brain, the digestive tract and the swimming muscles.
0:03:08 > 0:03:13It's a perfect predatory superpower that's clear to see in these mighty
0:03:13 > 0:03:14marine torpedoes.
0:03:16 > 0:03:21And it's this ingenious internal heating and explosive power that put
0:03:21 > 0:03:26the mako on to my list as one super speedy shark.
0:03:31 > 0:03:33If there were a prize for terrifying teeth,
0:03:33 > 0:03:36my next shark would definitely win it.
0:03:36 > 0:03:40Nudging in at nine is the ragged tooth shark,
0:03:40 > 0:03:42which certainly lives up to its name.
0:03:44 > 0:03:48They can measure over three metres in length, and spend their days
0:03:48 > 0:03:51hidden away in coral caves,
0:03:51 > 0:03:53or serenely surveying the seas.
0:03:54 > 0:03:56So why such gnarly gnashers?
0:03:58 > 0:04:01I got a closer look on South Africa's Indian Ocean coast.
0:04:05 > 0:04:07This is the time of day that we've been waiting for.
0:04:07 > 0:04:10It's dusk, the sun is just starting to go down and this is when things
0:04:10 > 0:04:12underwater get really interesting,
0:04:12 > 0:04:14particularly with sharks.
0:04:14 > 0:04:18A shark that during the day has been slow-moving, passive, almost lazy,
0:04:18 > 0:04:20can all of a sudden turn into a fast,
0:04:20 > 0:04:24fearsome and perhaps quite frightening animal with one thing
0:04:24 > 0:04:26on its mind - hunting.
0:04:28 > 0:04:32And it wasn't long before the sun had set and we lost
0:04:32 > 0:04:33all natural light.
0:04:34 > 0:04:36It's a bit spooky, really.
0:04:38 > 0:04:39There!
0:04:42 > 0:04:45A ragged tooth shark.
0:04:47 > 0:04:51Their teeth almost seem to spill out of their mouths.
0:04:54 > 0:04:57They have nearly 100 active needle-sharp teeth
0:04:57 > 0:04:59that are angled backwards,
0:04:59 > 0:05:02and these form a flawless fish trap.
0:05:04 > 0:05:07Menacing, maybe, but they're a perfect predatory tool.
0:05:11 > 0:05:15And it's not just the adults that have these fearsome fangs.
0:05:16 > 0:05:20Unborn babies have them, too, and not only that,
0:05:20 > 0:05:23but they use them...on each other.
0:05:24 > 0:05:29Pregnant females will only ever give birth to a maximum of two young,
0:05:29 > 0:05:34so the strongest will eat their brothers and sisters whilst still
0:05:34 > 0:05:38inside their mother's womb, making sure that they get a chance
0:05:38 > 0:05:39to survive.
0:05:40 > 0:05:44And it's this shocking secret that secures the ragged tooth shark its
0:05:44 > 0:05:49place on my list, and makes it the most sinister shark in our seas.
0:05:51 > 0:05:53Eating its way into eight
0:05:53 > 0:05:56is a shark with an insanely insatiable appetite.
0:05:58 > 0:05:59The tiger shark.
0:06:01 > 0:06:04Often nicknamed the dustbin of the ocean,
0:06:04 > 0:06:08they've been known to swallow tin cans, and even car number plates.
0:06:10 > 0:06:13But they prefer to munch on fast-moving fish
0:06:13 > 0:06:15and armoured turtles.
0:06:16 > 0:06:21I got a closer look at these stripy sharks off the coast of the Bahamas.
0:06:25 > 0:06:27Oh, my goodness.
0:06:28 > 0:06:29Well, this
0:06:29 > 0:06:31is why we came here to Tiger Beach.
0:06:33 > 0:06:35It's a true monster of a tiger shark.
0:06:35 > 0:06:37It's one the largest
0:06:37 > 0:06:40purely predatory creatures on earth.
0:06:40 > 0:06:42While I'm not on their menu,
0:06:42 > 0:06:44it doesn't stop them from being curious,
0:06:44 > 0:06:46and as sharks don't have hands,
0:06:46 > 0:06:48they'll investigate with their teeth.
0:06:48 > 0:06:50It's going for your fin, Si. No, draw in your foot.
0:06:50 > 0:06:52Draw in your foot, seriously.
0:06:52 > 0:06:53Whoa, whoa, whoa! Si, Si, Si!
0:06:57 > 0:06:59This is absolute chaos.
0:07:01 > 0:07:05They may be intrigued by us, but when they really want a meal,
0:07:05 > 0:07:08these hungry hunters rely on stealth to catch their prey.
0:07:11 > 0:07:13For a surprise attack,
0:07:13 > 0:07:17tiger sharks use camouflage known as countershading.
0:07:17 > 0:07:21In the ocean, light from the sun falls from above, and if you see
0:07:21 > 0:07:26this shark from underneath, its light belly blends in with the sky.
0:07:26 > 0:07:28But if you look down on the shark from above,
0:07:28 > 0:07:32you see its dark upper surface against the seabed below.
0:07:32 > 0:07:36But tiger sharks also ambush their prey at the surface,
0:07:36 > 0:07:39and that's where their stripy pattern comes in.
0:07:39 > 0:07:42It mimics the movement of light on the water,
0:07:42 > 0:07:43breaking up their outline and
0:07:43 > 0:07:46allowing for them to get close enough to their prey
0:07:46 > 0:07:47to launch an attack.
0:07:51 > 0:07:53Almost hidden in the shallows,
0:07:53 > 0:07:56tiger sharks wait for the perfect moment to strike,
0:07:56 > 0:07:59stealthily snatching their feathery feast.
0:08:02 > 0:08:06And it's this clever camouflage that sees them devour a place on my list
0:08:06 > 0:08:11as not only surprising, but as the most ravenous shark in our seas.
0:08:14 > 0:08:17Snapping in at seven is a shark with a bucket-load of bite...
0:08:19 > 0:08:20..the lemon shark.
0:08:21 > 0:08:25And not only are they snappy, these sharks are seriously smart.
0:08:27 > 0:08:30Female lemon sharks will return to exactly the same place that they
0:08:30 > 0:08:32were born to give birth to their young.
0:08:35 > 0:08:39They choose to do this in shallow water mangroves.
0:08:39 > 0:08:42The twisted roots offer the babies protection from larger predators as
0:08:42 > 0:08:44they grow up.
0:08:44 > 0:08:47And within this rich ecosystem is a constant supply of food.
0:08:50 > 0:08:53The youngsters spend around seven years here before heading out to
0:08:53 > 0:08:55deeper waters.
0:08:56 > 0:08:59So these mangroves are vital to their survival.
0:09:01 > 0:09:03But these shark safe havens are under threat.
0:09:05 > 0:09:09They're in the exact places where people want to build up tourism and
0:09:09 > 0:09:10hotel complexes.
0:09:11 > 0:09:15So if we want to protect sharks, we must also protect their homes...
0:09:16 > 0:09:19..allowing them to grow into the awesome adults they become.
0:09:20 > 0:09:24Once they're fully grown, they can reach around three metres in length,
0:09:24 > 0:09:27and it's the lemon sharks' yellow-tinged, pitted skin
0:09:27 > 0:09:29that earns them their name...
0:09:30 > 0:09:34..providing the perfect camouflage cover as they scour the sandy
0:09:34 > 0:09:37seabed for stingrays, crabs and crayfish.
0:09:40 > 0:09:43But what I love is how these sharks get a good grip on
0:09:43 > 0:09:44their hidden prey.
0:09:46 > 0:09:49The warm waters of the Caribbean are a great place to find them.
0:09:53 > 0:09:56Crazy as it seems, we're getting in there.
0:09:58 > 0:10:02To analyse this feisty shark's bite in three dimensions,
0:10:02 > 0:10:06we're heading in with a time slice rig made up of 20 small cameras.
0:10:09 > 0:10:11With seriously super senses,
0:10:11 > 0:10:15it doesn't take them long to suss out we have a box of fish with their
0:10:15 > 0:10:16name on it.
0:10:17 > 0:10:19There are sharks everywhere.
0:10:19 > 0:10:22I'm getting absolutely beaten up here.
0:10:23 > 0:10:25And after a little bit of feeding practice...
0:10:25 > 0:10:28Yes, perfect.
0:10:28 > 0:10:32..it's time to take a closer look at this shark's brilliant bite.
0:10:35 > 0:10:38The lemon shark's mouth is on the underside of its head,
0:10:38 > 0:10:40so in order to take a bite,
0:10:40 > 0:10:42it really needs to lift its snout,
0:10:42 > 0:10:47but it does have an extra adaptation to give it a bit more reach.
0:10:47 > 0:10:48In mammals like us,
0:10:48 > 0:10:53the upper jaw is fused to our skull and can't move, but in the shark's,
0:10:53 > 0:10:57both the upper and lower jaw can move freely, and lunge forward to
0:10:57 > 0:10:59capture prey.
0:11:02 > 0:11:06A marvellous modification for a far-reaching bite.
0:11:08 > 0:11:11And this free-moving jaw also allows them to open
0:11:11 > 0:11:13their mouths much wider,
0:11:13 > 0:11:16so small prey is simply hoovered up.
0:11:20 > 0:11:24So this savvy shark is one of my top ten favourites, and the snappiest
0:11:24 > 0:11:26shark in our seas.
0:11:30 > 0:11:34Securing spot six is a highly honed hunter with -
0:11:34 > 0:11:37let's be honest - a rather bizarrely shaped head.
0:11:40 > 0:11:41The hammerhead shark.
0:11:43 > 0:11:46Like all sharks, they have a sixth sense of finely tuned
0:11:46 > 0:11:49electroreceptors, to detect their dinner.
0:11:53 > 0:11:56But the hammerhead makes it onto my top ten because
0:11:56 > 0:11:58it is seriously supercharged.
0:12:00 > 0:12:03I was lucky enough to get a closer look at one in the warm waters of
0:12:03 > 0:12:05the Bahamas.
0:12:08 > 0:12:11This is one of the most awesome creatures in the sea.
0:12:11 > 0:12:15I don't believe it. It's a great hammerhead.
0:12:15 > 0:12:18You can instantly see how different it is.
0:12:19 > 0:12:24That hammer-shaped head is absolutely incredible.
0:12:24 > 0:12:29Their wide-set eyes give them almost 360 degrees of vision,
0:12:29 > 0:12:33helping them spot fast-moving prey like fish and squid.
0:12:33 > 0:12:36But it's their sensitive head that sets them apart from other sharks.
0:12:40 > 0:12:46The hammerhead's remarkable head is kind of a bit like a metal detector.
0:12:46 > 0:12:49All living things give off an electrical field.
0:12:49 > 0:12:54I am now. The shark's head is covered in tiny electroreceptors,
0:12:54 > 0:12:57which sense these electrical fields.
0:12:57 > 0:13:00They're called the ampullae of Lorenzini.
0:13:00 > 0:13:05A big great hammerhead's head could be a metre in width from eye to eye.
0:13:05 > 0:13:08This gives them more space for those ampullae
0:13:08 > 0:13:10compared to other species of sharks,
0:13:10 > 0:13:14making them much more accurate at scanning the seabed for food.
0:13:16 > 0:13:19Sweeping back and forth, they search for a signal,
0:13:19 > 0:13:22hunting down their prey like a marine metal detector.
0:13:24 > 0:13:28So the hammerhead secures a spot as one of my favourite sharks because
0:13:28 > 0:13:30of its sensational super senses.
0:13:34 > 0:13:37No shark programme would be complete without an appearance from the most
0:13:37 > 0:13:38famous shark of all.
0:13:40 > 0:13:43So, firing in at five is the mighty great white...
0:13:45 > 0:13:47..one of the greatest hunters on the planet.
0:13:51 > 0:13:56Reaching lengths of up to six metres and weighing as much as a car,
0:13:56 > 0:13:59great whites prey on fish and marine mammals like seals.
0:14:02 > 0:14:06And these colossal carnivores rule their waters.
0:14:09 > 0:14:12I was lucky enough to have the chance to swim alongside them
0:14:12 > 0:14:17in the open ocean off Guadalupe Island near the coast of Mexico.
0:14:19 > 0:14:22A lot of people might ask why I would even consider going outside of
0:14:22 > 0:14:26the cage with a great white shark, and for me, it's very simple.
0:14:26 > 0:14:30I spent a lot of my life trying to convince people that sharks are not
0:14:30 > 0:14:33the misunderstood man-eating monsters that a lot of people think
0:14:33 > 0:14:36they are, and this is kind of the best way of proving that.
0:14:36 > 0:14:40These animals have so much to fear from us, and we have next to nothing
0:14:40 > 0:14:41to fear from them.
0:14:43 > 0:14:46So, it was time for me to kit up and prove it.
0:14:50 > 0:14:54So, I think it's time to head out through the open cage door.
0:14:59 > 0:15:03Out of the blue and as if from nowhere, a shadow appeared.
0:15:03 > 0:15:06Look, look at that coming straight towards us.
0:15:09 > 0:15:12This stealthy approach is just one of the reasons
0:15:12 > 0:15:14they're such awesome predators.
0:15:16 > 0:15:18Another is those terrific teeth.
0:15:22 > 0:15:26The jaws of the great white are perhaps what this shark is best
0:15:26 > 0:15:27known for.
0:15:27 > 0:15:30And with good reason! At any one time,
0:15:30 > 0:15:34a great white may have 300 scalpel-sharp serrated teeth in its
0:15:34 > 0:15:40mouth in rows. The front row is used to capture and devour prey.
0:15:40 > 0:15:44The other rows are like spares on a conveyor belt.
0:15:44 > 0:15:48When the front row falls out, the others roll forward
0:15:48 > 0:15:49to take their place.
0:15:49 > 0:15:53This shark may get through 20,000 teeth in a lifetime,
0:15:53 > 0:15:56ensuring they never run out of their greatest asset.
0:15:59 > 0:16:03Team those serrated teeth with two tonnes of explosive power,
0:16:03 > 0:16:06and speeds of up to 40km an hour...
0:16:07 > 0:16:11..and this shark is able to drive its prey clear out of the water.
0:16:15 > 0:16:19So all of these perfect predatory tools propel the great white onto
0:16:19 > 0:16:24my top ten as one of the most ferocious fish in our seas.
0:16:28 > 0:16:30Now, nothing is more surprising than
0:16:30 > 0:16:33some seriously sensational superpowers,
0:16:33 > 0:16:36and in at four is my favourite shark superhero...
0:16:37 > 0:16:38..the epaulette shark.
0:16:40 > 0:16:44It's only found in the coastal waters of Australia and New Guinea.
0:16:44 > 0:16:46But unlike most sharks,
0:16:46 > 0:16:50it makes its home in shallow, tidal, coral-rich waters.
0:16:51 > 0:16:55So its speckled skin helps it blend into the background.
0:16:56 > 0:16:58Essential for a little fish
0:16:58 > 0:17:01that sits on the menu of its larger neighbours.
0:17:02 > 0:17:07So when they're around, the epaulette does well to stay hidden.
0:17:11 > 0:17:16But as the tide goes out, the larger sharks are forced to deeper waters,
0:17:16 > 0:17:20leaving the smaller epaulettes free run of the rock pools left behind...
0:17:22 > 0:17:25..where they search the cracks and crevices for their preferred prey of
0:17:25 > 0:17:27worms and crustaceans.
0:17:37 > 0:17:43But the tide hasn't stopped, and the epaulette is left high and dry.
0:17:47 > 0:17:50In order to breathe, all fish, including the sharks,
0:17:50 > 0:17:53need to extract oxygen from the water,
0:17:53 > 0:17:55but once the epaulette is on land,
0:17:55 > 0:17:58it needs to summon its superpower.
0:17:58 > 0:18:02First, it slows down its heart rate, and in turn,
0:18:02 > 0:18:05slows down the transfer of blood around the body.
0:18:05 > 0:18:10Secondly, it dilates or expands its blood vessels.
0:18:10 > 0:18:13This can reduce its blood pressure by as much as half.
0:18:14 > 0:18:17And finally, and perhaps most impressively,
0:18:17 > 0:18:20it reduces friction to vital areas of its brain.
0:18:21 > 0:18:23With all these things combined,
0:18:23 > 0:18:27this amazing shark can cope without oxygen for over an hour.
0:18:30 > 0:18:32And as if being a fish out of water wasn't enough...
0:18:34 > 0:18:36..this shark can walk.
0:18:39 > 0:18:43Its flexible fins allow it to push itself over the coral.
0:18:45 > 0:18:49So if all else fails, it can walk to water.
0:18:51 > 0:18:53And for all of these reasons,
0:18:53 > 0:18:58the epaulette shark definitely deserves its place on my top ten,
0:18:58 > 0:19:02as it's a shark with some seriously sensational superpowers.
0:19:06 > 0:19:10Thrashing in at number three is a solitary shark that roams the vast
0:19:10 > 0:19:11open ocean.
0:19:13 > 0:19:14The oceanic whitetip.
0:19:15 > 0:19:20Diving to depths of 1,000 metres and travelling up to 100km each day,
0:19:20 > 0:19:24they cruise the deep, desolate seas in their search for food.
0:19:26 > 0:19:29And it's their ludicrously large fins that help them
0:19:29 > 0:19:30navigate the abyss.
0:19:32 > 0:19:35Let's see it in action off Hawaii's Pacific Ocean coast.
0:19:39 > 0:19:43The oceanic whitetip, it is a deep-sea shark.
0:19:43 > 0:19:48It's what's known as a pelagic fish, one that sticks to the open ocean.
0:19:48 > 0:19:52They're mostly solitary, so incredibly difficult to find.
0:19:52 > 0:19:56But after three days of searching, we're in luck.
0:19:56 > 0:19:58We have a shark.
0:19:58 > 0:19:59Our first oceanic whitetip.
0:20:01 > 0:20:04Finding food is tough out here.
0:20:04 > 0:20:07These sharks need to make the most of every opportunity, so they
0:20:07 > 0:20:10immediately investigate us.
0:20:10 > 0:20:12She seems really interested in the cameras.
0:20:12 > 0:20:14And she's just testing them out,
0:20:14 > 0:20:16seeing if they might be something that's good to eat.
0:20:16 > 0:20:19So if they want to test something, want to feel what it's like,
0:20:19 > 0:20:22they have to do it with their teeth and with their snout.
0:20:22 > 0:20:26It's a feast-or-famine existence out here, but these ocean explorers have
0:20:26 > 0:20:30evolved perfectly to take on the epic expedition while
0:20:30 > 0:20:31looking for food.
0:20:34 > 0:20:37Earning its name from the distinctive white tips to its fins,
0:20:37 > 0:20:42the oceanic whitetip uses these tools to cross the great oceans.
0:20:42 > 0:20:47The pectoral fins are stiff and rigid, composed of keratin,
0:20:47 > 0:20:49cartilage and muscle.
0:20:49 > 0:20:52They function very much like the wings of a plane,
0:20:52 > 0:20:54preventing the shark from sinking.
0:20:54 > 0:20:56The dorsal fin stabilises the animal,
0:20:56 > 0:20:58preventing it from rolling over onto its back.
0:20:58 > 0:21:01It's almost like the keel on a boat.
0:21:01 > 0:21:05And the tail fin, that's very much the engine room of this predator,
0:21:05 > 0:21:07propelling it forward to catch fast food.
0:21:10 > 0:21:15Armed with these foolproof fins, they cruise the vast open oceans,
0:21:15 > 0:21:19making this a true adventurer of the abyss.
0:21:22 > 0:21:26And while these fabulous fins propel the oceanic whitetip
0:21:26 > 0:21:27onto my top ten,
0:21:27 > 0:21:30they're one of the main reasons that shark populations
0:21:30 > 0:21:32are in serious trouble.
0:21:35 > 0:21:39These fins, which give all sharks their control and power,
0:21:39 > 0:21:42are served as a delicacy in some parts of the world.
0:21:44 > 0:21:46In a soup.
0:21:46 > 0:21:49Prepare to be shocked.
0:21:49 > 0:21:53Did you know that the demand for shark fin soup means we're losing a
0:21:53 > 0:21:56staggering number of sharks from our seas?
0:21:56 > 0:22:00Around 11,000 sharks are killed every single hour
0:22:00 > 0:22:03at the hands of humans.
0:22:03 > 0:22:05And many of them purely for their fins.
0:22:06 > 0:22:10But sharks, no matter their shape or size, are an essential part of our
0:22:10 > 0:22:15marine ecosystem, and having evolved over 450 million years,
0:22:15 > 0:22:19they are, in my mind, some of the most magnificent creatures
0:22:19 > 0:22:19that we have.
0:22:24 > 0:22:28And getting back to my top ten, my next shark certainly proves that.
0:22:31 > 0:22:34This sleek silhouette secures second place.
0:22:36 > 0:22:37It's the thresher shark.
0:22:39 > 0:22:41A fish with a fantastic physique.
0:22:42 > 0:22:44Reaching up to six metres in length,
0:22:44 > 0:22:48these sharks come armed with a scythe-like tail that can be as long
0:22:48 > 0:22:49as their body.
0:22:51 > 0:22:54I got a closer look at them off the islands of the Philippines in
0:22:54 > 0:22:55south-east Asia.
0:22:57 > 0:22:59We head for the edge of the deep water,
0:22:59 > 0:23:02a sea stack reef where thresher sharks have been spotted before.
0:23:04 > 0:23:08And it's not long till a strange shape emerges from the dark.
0:23:09 > 0:23:11Coming towards us!
0:23:13 > 0:23:14No way!
0:23:17 > 0:23:20Oh, my... It's a thresher shark.
0:23:21 > 0:23:25This is one the greatest things I've ever seen.
0:23:25 > 0:23:29They're instantly recognisable with their long, elegant tail,
0:23:29 > 0:23:33and it's this that enables them to be a predator of precision.
0:23:36 > 0:23:40Thresher sharks feed on small, fast fish,
0:23:40 > 0:23:42but rather than chase them down,
0:23:42 > 0:23:45it corrals them the same way a cowboy would with its cattle.
0:23:45 > 0:23:47When small fish feel intimidated,
0:23:47 > 0:23:51they instinctively come together in a tight group known as a bait ball.
0:23:51 > 0:23:55And that's where the thresher shark's long tail comes in.
0:23:56 > 0:23:59It whips it over its head in about a third of a second,
0:23:59 > 0:24:04lashing out at the bait ball at about 30mph.
0:24:04 > 0:24:07This makes physical contact with the fish, but also creates a
0:24:07 > 0:24:11pressure wave that stuns them, making them easy pickings
0:24:11 > 0:24:13for the thresher.
0:24:15 > 0:24:18And with its prey cornered, the thresher shark moves in...
0:24:20 > 0:24:23..unleashing its killer tail to stun its supper.
0:24:26 > 0:24:30And for me, that's why the thresher shark is one of the most awesome and
0:24:30 > 0:24:32most striking of all the sharks.
0:24:35 > 0:24:38So what could possibly beat all of these stunning sharks?
0:24:40 > 0:24:43Choosing my all-time favourite has not been easy.
0:24:45 > 0:24:50But there's one truly gargantuan shark that completely blows my mind
0:24:50 > 0:24:51every single time.
0:24:53 > 0:24:55In at number one...
0:24:55 > 0:24:56is the whale shark.
0:24:58 > 0:25:03Not only is it the largest shark, but the largest fish in the world.
0:25:04 > 0:25:07Reaching record lengths of over 18 metres,
0:25:07 > 0:25:10which is longer than a double-decker bus,
0:25:10 > 0:25:13they can weigh in at a mighty 30 tonnes.
0:25:15 > 0:25:18Mozambique on the east coast of Africa is a great place
0:25:18 > 0:25:20to find them.
0:25:22 > 0:25:24Whale shark.
0:25:24 > 0:25:25Wow, look at the size of that!
0:25:25 > 0:25:28Huge! Right, we're looking good.
0:25:28 > 0:25:30OK, Eric. It's Steve in.
0:25:37 > 0:25:42Is there anything more majestic in the world's oceans?
0:25:44 > 0:25:48HE LAUGHS
0:25:44 > 0:25:48He's feeding!
0:25:48 > 0:25:54When it's eating like this, you can see that this is actually a hunter.
0:25:55 > 0:25:59And this shark has a very surprising diet.
0:26:01 > 0:26:05This gigantic creature consumes tens of thousands
0:26:05 > 0:26:08of tiny microscopic plankton -
0:26:08 > 0:26:10minute plants and animals that float in the water...
0:26:12 > 0:26:13..but are hardly visible to the eye.
0:26:16 > 0:26:18For an animal of this size,
0:26:18 > 0:26:22constantly chasing shoals of feisty fish would use far too much energy.
0:26:25 > 0:26:30So instead, these colossal creatures cruise around making the most of
0:26:30 > 0:26:32this super-abundant food supply...
0:26:33 > 0:26:34..with their mammoth mouths.
0:26:37 > 0:26:40Whale sharks are what are known as filter feeders.
0:26:40 > 0:26:44Water passes into their enormous mouths before heading over 20
0:26:44 > 0:26:48filtering pads which separate their plankton prey from the water.
0:26:48 > 0:26:52The water continues down and out through the gills, while the heavier
0:26:52 > 0:26:55plankton concentrates into a big ball and is swallowed down
0:26:55 > 0:26:56into the stomach.
0:26:59 > 0:27:01You know...
0:27:01 > 0:27:04..it's such a huge creature,
0:27:04 > 0:27:07it's one of the wonders of nature that all the things it feeds
0:27:07 > 0:27:10on are so tiny.
0:27:12 > 0:27:15So the whale shark's surprising diet,
0:27:15 > 0:27:19mega mouth and gargantuan size mean I had to make it
0:27:19 > 0:27:23my all-time favourite, the most colossal shark of all.
0:27:26 > 0:27:31So there we have it, my ten favourite shark bites.
0:27:31 > 0:27:35Look at the size of that tail! That is just insane!
0:27:35 > 0:27:39And for me, with all of the startling secrets they've revealed,
0:27:39 > 0:27:42there's no doubt that there's much more to sharks
0:27:42 > 0:27:44than first meets the eye.
0:27:44 > 0:27:45Such dramatic animals.
0:27:47 > 0:27:51They've patrolled our seas since long before the dinosaurs,
0:27:51 > 0:27:54so I think it's time we learnt not just to fear,
0:27:54 > 0:27:58but to admire and respect these lords of the sea.