0:00:02 > 0:00:04My name's Steve Backshall...
0:00:06 > 0:00:09..and this is my search for the Deadly 60.
0:00:10 > 0:00:11Amazing!
0:00:11 > 0:00:14That's not just animals that are deadly to me...
0:00:14 > 0:00:17but that are deadly in their own world.
0:00:17 > 0:00:19My crew and I are travelling the planet.
0:00:19 > 0:00:22And you're coming with me, every step of the way.
0:00:26 > 0:00:27Agh!
0:00:30 > 0:00:32For me, Deadly 60 is all about finding out
0:00:32 > 0:00:35what's unique and unusual about deadly animals,
0:00:35 > 0:00:37but we can only go so far. Until now.
0:00:37 > 0:00:41Today, we're going to find out what makes deadly animals tick.
0:00:41 > 0:00:44We're getting inside their heads, inside their skulls.
0:00:44 > 0:00:46We're going Inside Deadly 60.
0:00:53 > 0:00:55This is the Oxford Museum of Natural History,
0:00:55 > 0:00:59and it is my favourite building in the world.
0:01:00 > 0:01:04In this great hall, and endless dusty rooms beyond,
0:01:04 > 0:01:06there's fur and feathers,
0:01:06 > 0:01:10skulls and skeletons, from almost every animal on the planet.
0:01:10 > 0:01:14And to me, these are so much more than just dead animals.
0:01:14 > 0:01:16You can learn so much about creatures
0:01:16 > 0:01:19from their skulls, their skeletons, their teeth -
0:01:19 > 0:01:22how they live, what they feed on, and how they hunt.
0:01:29 > 0:01:32In this special, we're going to have a look inside
0:01:32 > 0:01:35some of the top predators we've encountered on Deadly 60.
0:01:37 > 0:01:40We're going to look under the skin, ruffle some feathers,
0:01:40 > 0:01:44stick our heads in the mouths of these lethal predators,
0:01:44 > 0:01:48and uncover what makes them such successful hunters.
0:01:54 > 0:01:56We couldn't come to a natural history museum
0:01:56 > 0:01:59without at least mentioning the mightiest predators
0:01:59 > 0:02:02that ever roamed the planet - the dinosaurs.
0:02:02 > 0:02:05This is a T-rex, and if he was alive today,
0:02:05 > 0:02:08he would certainly make it onto the Deadly 60.
0:02:08 > 0:02:11In fact, he'd probably eat all the other animals.
0:02:11 > 0:02:14But believe it or not, we already have on our list
0:02:14 > 0:02:17plenty of creatures that are descended from the dinosaurs.
0:02:19 > 0:02:23The animals I'm talking about are all around us.
0:02:24 > 0:02:26They are...the birds.
0:02:30 > 0:02:33Scientists have found many similarities between birds
0:02:33 > 0:02:35and dinosaur skeletons.
0:02:37 > 0:02:39Fossils have shown that dinosaur scales
0:02:39 > 0:02:41may have evolved into feathers.
0:02:44 > 0:02:49If it seems far-fetched that today's birds are descended from dinosaurs,
0:02:49 > 0:02:51have a look at this.
0:02:51 > 0:02:55This is the skeleton of a moa - a giant, flightless bird
0:02:55 > 0:02:59which only went extinct about 400 years ago in New Zealand.
0:02:59 > 0:03:05Have a look at those legs and feet. They look just like a dinosaur.
0:03:07 > 0:03:10Absolutely exactly the same.
0:03:10 > 0:03:16And, looking at that, it's not that much different from...this.
0:03:16 > 0:03:20This is an ostrich, and this is a completely modern bird.
0:03:20 > 0:03:23These are around us now and look at those -
0:03:23 > 0:03:27those could easily be the legs and feet of a dinosaur.
0:03:30 > 0:03:32Ostrich haven't made it onto the Deadly 60.
0:03:32 > 0:03:35But birds that have are the birds of prey.
0:03:35 > 0:03:38And this is a skeleton from a white-tailed eagle.
0:03:38 > 0:03:41There's a lot of things about this that are very special.
0:03:41 > 0:03:46The skull has a fiercely sharp, hooked beak.
0:03:46 > 0:03:50Very, very light, because there's no teeth inside.
0:03:50 > 0:03:55Here, I'm going very carefully because this is ever so fragile...
0:03:55 > 0:04:00Look at this breast bone - it's absolutely massive.
0:04:00 > 0:04:02And that's for attaching the flight muscles -
0:04:02 > 0:04:06those incredibly huge pectoral muscles that drive the wings
0:04:06 > 0:04:08and allow it to fly, like this.
0:04:08 > 0:04:13We're big fans of the birds of prey here on Deadly 60,
0:04:13 > 0:04:17and quite a few have earned a place on my list.
0:04:17 > 0:04:19We've raced a peregrine falcon...
0:04:21 > 0:04:23..been hunted by a goshawk...
0:04:25 > 0:04:29..seen the teamwork of vultures...
0:04:29 > 0:04:33experienced the sheer size and majesty of the harpy eagle,
0:04:33 > 0:04:37and in South Africa, had the honour of flying with a black eagle,
0:04:37 > 0:04:42to see how effortlessly they soar the skies in search of their prey.
0:04:44 > 0:04:46Run, run, run!
0:04:48 > 0:04:50And there he is, look!
0:04:50 > 0:04:55We're sharing the air with a black eagle! How good is that?
0:04:58 > 0:04:59I'm having to use a paraglider -
0:04:59 > 0:05:02and the skills of its very experienced pilot -
0:05:02 > 0:05:04just to stay airborne.
0:05:04 > 0:05:08But with a twitch of its tail, and a slight adjustment of its wings,
0:05:08 > 0:05:12this beautiful bird can turn, soar and dive at incredible speeds
0:05:12 > 0:05:14towards its supper.
0:05:17 > 0:05:20The birds of prey are truly masters of the air.
0:05:20 > 0:05:22To help them achieve this,
0:05:22 > 0:05:25they all have a secret hidden under their feathers.
0:05:25 > 0:05:30And to find out what it is, we have to look closely at their bones.
0:05:32 > 0:05:35The thing that keeps birds airborne is lift,
0:05:35 > 0:05:38and the biggest enemy of lift is weight.
0:05:38 > 0:05:41So, everything about the bones of birds of prey
0:05:41 > 0:05:44is all about keeping them as light as possible.
0:05:44 > 0:05:47And to give you a demonstration of quite how light they are,
0:05:47 > 0:05:52these are all of the bones from one white-tailed sea-eagle.
0:05:53 > 0:05:57I know it's a little bit grim having them in a pan like this,
0:05:57 > 0:06:00but...if I put those on one scale there,
0:06:05 > 0:06:07I have here a bag of sugar.
0:06:07 > 0:06:11Let's have a go and see how they balance.
0:06:13 > 0:06:16A full bag of sugar weighs about a kilogram.
0:06:16 > 0:06:19Whoa! Almost there.
0:06:21 > 0:06:24OK, so it's just about balancing now.
0:06:24 > 0:06:26That is utterly remarkable.
0:06:27 > 0:06:32So just how can an eagle this size weigh so little?
0:06:32 > 0:06:36Well, the answer lies in its skeleton.
0:06:36 > 0:06:38The bones of birds aren't solid,
0:06:38 > 0:06:41but are made up of a honeycomb-like structure.
0:06:41 > 0:06:44This makes them strong, yet much lighter.
0:06:44 > 0:06:48They also minimise their weight by having no large jaw bone,
0:06:48 > 0:06:52no teeth, small skulls and small tail bones.
0:06:57 > 0:06:59We're talking about a bird of prey
0:06:59 > 0:07:03that can take things as large as a fox or a sheep,
0:07:03 > 0:07:07and its bones weigh about the same as half a bag of sugar.
0:07:07 > 0:07:10That is totally remarkable.
0:07:12 > 0:07:15All birds of prey have this ultra-lightweight skeleton.
0:07:15 > 0:07:18Combine this with razor-sharp claws and beak,
0:07:18 > 0:07:20and they're pound-for-pound
0:07:20 > 0:07:22some of the deadliest predators on the planet.
0:07:34 > 0:07:37For me, the most beautiful skeletons of any animals
0:07:37 > 0:07:40are those that belong to the snakes,
0:07:40 > 0:07:43and I think they really tell a very strong story as well.
0:07:43 > 0:07:48This here is the skeleton of a very large-bodied heavy snake.
0:07:48 > 0:07:49It's a python of some kind.
0:07:49 > 0:07:53Now, I can't touch this one because it's quite an old skeleton,
0:07:53 > 0:07:55and it might fall apart.
0:07:55 > 0:07:59But what I can do is show you up close - using this little camera -
0:07:59 > 0:08:02what it feels like to fly alongside
0:08:02 > 0:08:08the skeleton of a truly giant snake.
0:08:08 > 0:08:12OK, here at the top, that's the backbone - the vertebrae.
0:08:12 > 0:08:15You can see they're all tightly linked together.
0:08:17 > 0:08:19This interlocking spine
0:08:19 > 0:08:23gives the snake's backbone rigidity and strength.
0:08:25 > 0:08:27And running down here...
0:08:27 > 0:08:30these are its ribs.
0:08:30 > 0:08:34It's obviously got rather more than we have, and the reason
0:08:34 > 0:08:37that that is so important is that muscles attach to bones,
0:08:37 > 0:08:42and where they do attach to bones is where they're at their strongest.
0:08:42 > 0:08:47So, we've got hundreds of ribs alongside each other,
0:08:47 > 0:08:48forming a cage like this.
0:08:48 > 0:08:52The muscles that attach to them can be really, really strong.
0:08:52 > 0:08:56And that relates to how this particular animal hunts.
0:08:56 > 0:08:59It uses those powerful muscles to constrict -
0:08:59 > 0:09:02that is, to squeeze the life out of - its prey.
0:09:04 > 0:09:07I had first-hand experience of a constrictor's power
0:09:07 > 0:09:10when I got into a rather tight squeeze
0:09:10 > 0:09:13with a boa constrictor in Costa Rica.
0:09:14 > 0:09:16This is what constricting means.
0:09:16 > 0:09:20If you see me starting to go blue or purple in the face,
0:09:20 > 0:09:22then I might need a little bit of help!
0:09:22 > 0:09:26Constricting basically means to strangle -
0:09:26 > 0:09:28to suffocate the life out of prey.
0:09:28 > 0:09:34And that's how this magnificent animal...
0:09:34 > 0:09:36SNAKE HISSES ANGRILY
0:09:36 > 0:09:41..manages to kill the mammals it's feeding on.
0:09:41 > 0:09:44Ooh! Its tail's going round the back of my neck now.
0:09:44 > 0:09:49It's just finding places and ways of getting purchase
0:09:49 > 0:09:54to use its really strong muscles in choking me.
0:09:54 > 0:09:58But the snake wouldn't have anywhere near the same strength
0:09:58 > 0:10:01if it didn't have all those ribs to attach its muscles to.
0:10:08 > 0:10:13Actually...yeah...it's amazing how strong it is!
0:10:13 > 0:10:18I mean, this snake is only actually feeding on mammals
0:10:18 > 0:10:22about that sort of size, maximum.
0:10:22 > 0:10:25And it has the strength to choke the life out of me.
0:10:25 > 0:10:31I mean, I must be ten times, twenty times the size of its normal prey,
0:10:31 > 0:10:34and he easily has enough strength to choke me!
0:10:37 > 0:10:40Constrictors will occasionally take on
0:10:40 > 0:10:42much larger animals than themselves.
0:10:42 > 0:10:45So what happens when the meal you're trying to eat
0:10:45 > 0:10:47is four times as wide as your mouth?
0:10:49 > 0:10:53Well, the way they deal with this mouth-splitting meal...
0:10:53 > 0:10:55is pretty horrendous.
0:11:02 > 0:11:06So far, so frightening, but it gets even better
0:11:06 > 0:11:12when you get a look inside one of those big snake's mouths.
0:11:12 > 0:11:17Right... this utterly horrifying skull
0:11:17 > 0:11:20belongs to an African rock python.
0:11:20 > 0:11:22I've got to be very careful how I handle it.
0:11:22 > 0:11:26But this really shows you why it is such a ferocious predator.
0:11:26 > 0:11:28You can see the teeth are so sharp,
0:11:28 > 0:11:32they're actually getting stuck on my rubber gloves.
0:11:32 > 0:11:35They point backwards so that once it's got a hold of its prey,
0:11:35 > 0:11:36it doesn't let go,
0:11:36 > 0:11:39and then...
0:11:39 > 0:11:44along the top jaw is an extra two rows of teeth.
0:11:44 > 0:11:47That is a really scary mouth.
0:11:47 > 0:11:50But that is not what is most remarkable about this skull.
0:11:50 > 0:11:53The incredible thing is that a snake that big
0:11:53 > 0:11:57can swallow things that are bigger than its own head.
0:11:57 > 0:11:59The way it does that is that back here,
0:11:59 > 0:12:02it has particularly stretchy ligaments
0:12:02 > 0:12:06to allow this jaw and the upper jaw to really stretch apart
0:12:06 > 0:12:08and be absolutely massive.
0:12:08 > 0:12:13And then here, on the lower jaw, it's not joined at all.
0:12:13 > 0:12:19That allows these two independent sections of the lower jaw
0:12:19 > 0:12:24to walk their way down prey, swallowing it whole.
0:12:26 > 0:12:27But it doesn't stop there.
0:12:27 > 0:12:31This snake can divide not just its lower jaw in two,
0:12:31 > 0:12:33but can also divide its upper jaw,
0:12:33 > 0:12:36so that its head is in four main sections.
0:12:36 > 0:12:40Two halves of the lower jaw and two halves of the upper jaw.
0:12:42 > 0:12:44Elastic ligaments connect the four sections,
0:12:44 > 0:12:46allowing them to move independently.
0:12:46 > 0:12:50The snake's jaws walk over the prey,
0:12:50 > 0:12:53guiding its victim down into its stomach...
0:12:53 > 0:12:57where acids will break down the bones, hooves and horns
0:12:57 > 0:13:00into liquid nourishment.
0:13:01 > 0:13:04And whereas our ribs join at our chest,
0:13:04 > 0:13:08the python's aren't connected...
0:13:11 > 0:13:13..and can expand to enable it
0:13:13 > 0:13:18to consume an animal three times as wide as its own head.
0:13:23 > 0:13:27This snake might not eat again for a whole year.
0:13:31 > 0:13:34Some of the most exciting encounters we've had on Deadly 60,
0:13:34 > 0:13:38and sometimes the most frightening, have been with fish,
0:13:38 > 0:13:42but very big fish, with very big teeth.
0:13:42 > 0:13:45I'm talking about the sharks.
0:13:47 > 0:13:52On the Deadly 60, we've met loads of sharks. From the whale shark -
0:13:52 > 0:13:54the biggest fish in the sea...
0:13:54 > 0:13:58What a wonderful, beautiful giant!
0:13:58 > 0:14:01..to sleeker, more nimble blacktip sharks.
0:14:01 > 0:14:03Wow!
0:14:04 > 0:14:08In the Philippines, we met the mysterious thresher shark.
0:14:10 > 0:14:15And in South Africa, the ragged tooth shark.
0:14:18 > 0:14:19Now, I am a total shark freak,
0:14:19 > 0:14:23and I reckon there's few more impressive things in the world
0:14:23 > 0:14:25than looking inside the mouth of a shark.
0:14:25 > 0:14:29This here is from a shortfin mako shark.
0:14:29 > 0:14:32It's one of the fastest sharks in the sea.
0:14:32 > 0:14:34The jaw itself is not actually made of bone.
0:14:34 > 0:14:37It's made of a softer substance called cartilage.
0:14:37 > 0:14:40But there's nothing soft about these teeth.
0:14:43 > 0:14:45Because the mako shark feeds on fish,
0:14:45 > 0:14:47which are slimy and slippery and quick,
0:14:47 > 0:14:51the teeth themselves are quite thin, point backwards,
0:14:51 > 0:14:53and they're impossibly sharp.
0:14:53 > 0:14:57If I was to actually rub my finger down that edge there,
0:14:57 > 0:14:59I'd probably get cut.
0:14:59 > 0:15:03It's mightily impressive. And look at the way here,
0:15:03 > 0:15:07the teeth almost seem to spill right out of the mouth,
0:15:07 > 0:15:10forming a working fish trap.
0:15:10 > 0:15:14This, however, is very, very different.
0:15:14 > 0:15:17And that's because this is a tiger shark,
0:15:17 > 0:15:19and it feeds on completely different things.
0:15:19 > 0:15:25Tiger sharks are swimming dustbins, and will eat just about anything.
0:15:25 > 0:15:29They do eat fish, but they'll happily also eat sea birds...
0:15:30 > 0:15:33..other sharks...
0:15:33 > 0:15:35and even sea turtles.
0:15:35 > 0:15:39But how do they get through the turtle's protective shell?
0:15:41 > 0:15:44If I open this up, wow!
0:15:44 > 0:15:46Right, you can instantly see
0:15:46 > 0:15:48how different those teeth are.
0:15:48 > 0:15:53In close-up, they have a serrated edge, just like a kitchen knife,
0:15:53 > 0:15:55and work almost like a can opener.
0:15:55 > 0:15:57The tiger shark can actually bite
0:15:57 > 0:16:00clean through the shells of sea turtles,
0:16:00 > 0:16:03which is one of its favourite foods.
0:16:03 > 0:16:06But it gets even cooler.
0:16:06 > 0:16:08If I turn this around slightly,
0:16:08 > 0:16:12and you look at the inside of the jaw...
0:16:13 > 0:16:20..lined up there are one, two, three, four, five rows of teeth,
0:16:20 > 0:16:23all waiting to spring into position when the front one breaks.
0:16:23 > 0:16:25It's like a conveyor belt of teeth
0:16:25 > 0:16:28that keeps on going through the shark's life,
0:16:28 > 0:16:30so it doesn't matter if it loses a tooth -
0:16:30 > 0:16:33another one will just roll into its place.
0:16:33 > 0:16:36This would have to be the most formidable predator in the sea.
0:16:41 > 0:16:44I was lucky enough to swim with these magnificent predators
0:16:44 > 0:16:47when the crew and I travelled to the Bahamas.
0:16:51 > 0:16:55Look! That's a seriously big tiger coming in!
0:16:55 > 0:16:57A big female!
0:16:58 > 0:17:02Not only do tiger sharks have serrated teeth,
0:17:02 > 0:17:04but they can get to be huge.
0:17:09 > 0:17:11This female tiger shark
0:17:11 > 0:17:14looks to be twice the size of our cameraman, Simon.
0:17:30 > 0:17:32All my years diving with sharks,
0:17:32 > 0:17:35and they still have the power to surprise me.
0:17:35 > 0:17:38Even that huge bulldog of a female tiger
0:17:38 > 0:17:42was just nosing cautiously between Simon the cameraman and I.
0:17:42 > 0:17:45It was almost like she was being polite,
0:17:45 > 0:17:47she didn't want to jump the queue!
0:17:47 > 0:17:52For all that, though, the tiger shark has to be on the Deadly 60.
0:17:52 > 0:17:56They're big, they're powerful, they have enormous can opener teeth,
0:17:56 > 0:17:59and they're one of the wonders of the ocean.
0:17:59 > 0:18:01That was incredible.
0:18:06 > 0:18:08Over the course of Deadly 60,
0:18:08 > 0:18:11there's one group of animals I keep coming back to,
0:18:11 > 0:18:14because nobody is ever going to doubt that they're deadly.
0:18:14 > 0:18:17And I'm talking about the crocodilians.
0:18:17 > 0:18:19Gharials,
0:18:19 > 0:18:21caiman,
0:18:21 > 0:18:24and the crocodiles.
0:18:26 > 0:18:29This here is the skeleton of a Nile crocodile.
0:18:29 > 0:18:32It's one of the largest reptiles in the world,
0:18:32 > 0:18:35and one of the fiercest crocodiles.
0:18:35 > 0:18:38This one is about 2.5 metres long. They get to be about six.
0:18:38 > 0:18:45Yep, you heard right - six metres! That's as long as a minibus.
0:18:45 > 0:18:48OK, let's get down to specifics. This is the neck, here.
0:18:48 > 0:18:52And you can see that the vertebrae are tightly packed,
0:18:52 > 0:18:55which gives it a rigid, strong structure.
0:18:55 > 0:18:58Just like in constricting snakes,
0:18:58 > 0:19:01this gives the backbone added strength...
0:19:02 > 0:19:05..and allows the crocodile to rip its head from side to side
0:19:05 > 0:19:11and take down enormous prey - things as big as buffalo.
0:19:17 > 0:19:21But how do such enormous predators track down their prey?
0:19:23 > 0:19:27Well, they use the first of many lethal attributes.
0:19:30 > 0:19:33Living in water, crocs need to be able to open their mouths
0:19:33 > 0:19:34without the risk of drowning.
0:19:34 > 0:19:36When the head's submerged,
0:19:36 > 0:19:39a valve at the back of the tongue seals the throat
0:19:39 > 0:19:43and completely stops water pouring down into the lungs.
0:19:43 > 0:19:47Air tubes open behind this valve and run to the nostrils
0:19:47 > 0:19:49enabling the crocs to breathe
0:19:49 > 0:19:52as they lie concealed beneath the water's surface.
0:19:56 > 0:19:58They can lie underwater not breathing
0:19:58 > 0:20:00for as long as three hours.
0:20:00 > 0:20:03And in order to conserve oxygen and energy,
0:20:03 > 0:20:07they can slow their heart rate from 40 to three beats per minute.
0:20:10 > 0:20:12So that's all pretty impressive,
0:20:12 > 0:20:15but let's come to the business end of the beast.
0:20:15 > 0:20:18This is the skull. This is from quite a decent sized Nile croc.
0:20:18 > 0:20:24And the most noticeable thing is just the incredible weight of it.
0:20:24 > 0:20:27I mean, it's probably about the weight of a sack of potatoes.
0:20:27 > 0:20:30I couldn't hold it like this for much longer,
0:20:30 > 0:20:33so I'm going to put it down.
0:20:33 > 0:20:35That huge head houses
0:20:35 > 0:20:38some of the strongest jaws in the animal kingdom.
0:20:38 > 0:20:41And also some of the most brutal teeth.
0:20:44 > 0:20:47OK, let's get a look at these fantastic teeth.
0:20:47 > 0:20:51That one there is probably the most impressive.
0:20:51 > 0:20:53It's about the size of my thumb.
0:20:53 > 0:20:59These teeth interlock and spill out of the jaw.
0:20:59 > 0:21:03They keep on growing and they get replaced if they get broken.
0:21:03 > 0:21:07Now that is a serious set of gnashers.
0:21:09 > 0:21:14With their formidable deadly attributes - powerful jaws,
0:21:14 > 0:21:19pointed teeth and stealth skills - crocodiles are the perfect predator.
0:21:32 > 0:21:36It's easy to see crocs as prehistoric dinosaurs,
0:21:36 > 0:21:40but they actually highly sophisticated creatures.
0:21:42 > 0:21:44Not only that, but at feeding time,
0:21:44 > 0:21:48they often reveal an unexpectedly social side.
0:21:48 > 0:21:53After a croc makes a kill, others come and join the feast.
0:21:55 > 0:22:00While some crocs will anchor the prey down using their huge jaws,
0:22:00 > 0:22:05another takes a bite, locks its neck and back muscles,
0:22:05 > 0:22:08and begins to spin.
0:22:08 > 0:22:13This is known as the death roll, and something has to give.
0:22:17 > 0:22:21The croc tears off a chunk of meat, which can be quite a mouthful.
0:22:23 > 0:22:28A large crocodile's bite is five times more powerful than a lion's.
0:22:30 > 0:22:33Working together, every last bit is eaten.
0:22:35 > 0:22:40Bones, horns, hooves. Nothing is left to waste.
0:22:48 > 0:22:51Crocodiles often lose teeth doing this,
0:22:51 > 0:22:55but for them, it's no big deal.
0:22:55 > 0:23:00Over their lifetime, they can grow up to 3,000 new ones.
0:23:03 > 0:23:07But not all reptiles use force - brute force and strength -
0:23:07 > 0:23:08to hunt down their prey.
0:23:10 > 0:23:13In this box, I've got a very different kind of skull.
0:23:13 > 0:23:16This belongs to a monitor lizard.
0:23:16 > 0:23:20It's also a reptile, but it couldn't be more different.
0:23:23 > 0:23:27While the crocodile's skull is incredibly bony and heavy -
0:23:27 > 0:23:30all of the gaps are filled in with thick bone -
0:23:30 > 0:23:33this monitor lizard's skull is incredibly light.
0:23:33 > 0:23:36You can see that instead of thick bone,
0:23:36 > 0:23:38it has tiny little struts to hold the skull together.
0:23:38 > 0:23:40That means it's much lighter,
0:23:40 > 0:23:43and the animal itself can be much faster over longer distances
0:23:43 > 0:23:45and longer periods of time.
0:23:49 > 0:23:52It's that lightweight skeleton that makes monitor lizards
0:23:52 > 0:23:55one of the most versatile hunters of the reptile world.
0:23:58 > 0:24:00They're nimble climbers,
0:24:00 > 0:24:02even expert divers.
0:24:02 > 0:24:06Whatever it takes to get a meal.
0:24:06 > 0:24:08And as well as killer claws,
0:24:08 > 0:24:11they carry a face full of ferocious teeth.
0:24:15 > 0:24:17Get a load of those teeth.
0:24:17 > 0:24:20Very, very different to the crocodile teeth.
0:24:20 > 0:24:24They're curved backwards, so that once this gets a bite on something,
0:24:24 > 0:24:26it's certainly not letting go.
0:24:26 > 0:24:29And these are the lower jaws.
0:24:29 > 0:24:31If you see that together,
0:24:31 > 0:24:35you can also see that the bottom jaw has enough movement
0:24:35 > 0:24:37to allow the monitor lizard
0:24:37 > 0:24:40to take bites out of the things that it's feeding on.
0:24:42 > 0:24:46So, we've seen how its lightweight skeleton and gripping claws
0:24:46 > 0:24:49make it ultra-rapid when chasing down prey.
0:24:49 > 0:24:51Add to that its fiercely sharp teeth,
0:24:51 > 0:24:54and jaws that allow the monitor lizard
0:24:54 > 0:24:56to crush the skull of its prey in one bite,
0:24:56 > 0:25:01and you can see why they had to be on the Deadly 60.
0:25:02 > 0:25:05I've seen these animals in the wild, and believe me,
0:25:05 > 0:25:07they are absolutely fearsome.
0:25:07 > 0:25:12Everyone keep your eyes peeled and give me a shout if you see anything.
0:25:12 > 0:25:14In the Philippines, we heard that monitor lizards
0:25:14 > 0:25:18were sniffing around the garbage heaps of a local village.
0:25:18 > 0:25:21And it wasn't long before we came face to face with one.
0:25:21 > 0:25:22(He's there!)
0:25:32 > 0:25:37This is a bit closer than I would really be comfortable with.
0:25:37 > 0:25:43Inside that mouth is one long line of teeth
0:25:43 > 0:25:46that are honestly razor-sharp,
0:25:46 > 0:25:51backwards curving, and covered with...
0:25:54 > 0:25:56He's tasting my face!
0:25:56 > 0:25:58He just stuck his tongue in my eye!
0:26:03 > 0:26:06OK, this is where I start to get a little bit nervous.
0:26:06 > 0:26:08He can move very, very fast.
0:26:08 > 0:26:11From there, he can have his arm in his mouth in a second.
0:26:11 > 0:26:14Look at him tasting my hand!
0:26:19 > 0:26:24As I was saying, the mouth has razor-sharp teeth
0:26:24 > 0:26:27which are covered in bacteria.
0:26:27 > 0:26:32And those bacteria, once they get into a wound, once he cuts you open,
0:26:32 > 0:26:36will almost instantly start to become infected.
0:26:36 > 0:26:40Any bite from a monitor lizard is very, very serious indeed.
0:26:42 > 0:26:46Luckily, this guy can see that I'm not food.
0:26:53 > 0:26:55So, our Deadly 60 superheroes -
0:26:55 > 0:26:58from birds of prey to sharks to crocodiles -
0:26:58 > 0:27:00are phenomenally complex machines.
0:27:00 > 0:27:03And these skeletons are the structures which drive them.
0:27:03 > 0:27:07They're incredibly different, but they have a lot in common, too.
0:27:07 > 0:27:11There's so much more than meets the eye to animals, so much to learn.
0:27:11 > 0:27:14All you have to do is get really under their skin!
0:27:20 > 0:27:21Ow!
0:27:21 > 0:27:24Ooh! Just stung right into the end of the tongs.
0:27:24 > 0:27:31Join me next time for more animal encounters on Deadly 60.
0:27:31 > 0:27:33Ooh! He actually flicked venom straight at me.
0:27:44 > 0:27:47Subtitles by Red Bee Media Ltd
0:27:47 > 0:27:50E-mail subtitling@bbc.co.uk