0:00:02 > 0:00:03My name is Steve Backshall.
0:00:04 > 0:00:06People call me Steve.
0:00:09 > 0:00:12I'm on a mission to find the Deadly 60.
0:00:12 > 0:00:17'That's 60 deadly creatures from around the world.
0:00:17 > 0:00:19'And you're coming with me every step of the way.'
0:00:20 > 0:00:22Ow!
0:00:29 > 0:00:32'Time to hit the trail and see what animals are worthy of making it
0:00:32 > 0:00:35'onto my Deadly 60.'
0:00:35 > 0:00:38We're here, in Arizona's Sonoran Desert.
0:00:39 > 0:00:41'This is the hottest area of the USA,
0:00:41 > 0:00:44'with temperatures getting to over 50 degrees.
0:00:44 > 0:00:48'But deadly environments go hand in hand with deadly animals.
0:00:48 > 0:00:50'We're in the right place.'
0:00:50 > 0:00:52It may get ridiculously hot here,
0:00:52 > 0:00:56but it's not as bleak or unforgiving as many deserts in the world,
0:00:56 > 0:00:58and there's loads of wildlife here.
0:00:58 > 0:01:03In amongst these plants are plenty of ground squirrels, rats, rabbits,
0:01:03 > 0:01:06all sorts of potential prey for predators.
0:01:06 > 0:01:08But they're very fast and very elusive.
0:01:08 > 0:01:11That's not a problem, though, for the birds of prey,
0:01:11 > 0:01:15masters of the sky here by day - and by night.
0:01:15 > 0:01:18'And I'll need a bird of the night
0:01:18 > 0:01:21'to call in my next deadly contender.'
0:01:21 > 0:01:24This impossibly beautiful creature
0:01:24 > 0:01:28is one of the fiercest predators found around here.
0:01:28 > 0:01:31It's a Great Horned Owl.
0:01:31 > 0:01:34And though she might just look very pretty,
0:01:34 > 0:01:37if you're a small mammal running through these bushes,
0:01:37 > 0:01:40this would be your living nightmare.
0:01:40 > 0:01:45Those horns which give it its name aren't actually ears at all.
0:01:45 > 0:01:47Those are just tufts of feathers.
0:01:47 > 0:01:49The ears are actually located...
0:01:49 > 0:01:53I'm a bit nervous about showing you this cos I might lose a finger,
0:01:53 > 0:01:56but just round to the side of the eyes,
0:01:56 > 0:02:00those dark shapes actually mark the ears.
0:02:00 > 0:02:04One is slightly higher than the other on each side of the head.
0:02:04 > 0:02:06So when you see an owl doing this -
0:02:06 > 0:02:08that very distinctive movement -
0:02:08 > 0:02:11it's figuring out what's happening around it
0:02:11 > 0:02:14by the sounds that are coming in and their relationship to the ears.
0:02:14 > 0:02:15SQUAWKS
0:02:15 > 0:02:19'I'm hoping that this bird will act as a sort of a lure.'
0:02:19 > 0:02:23There's another bird which flies mostly during the daytime
0:02:23 > 0:02:27and is the sworn enemy of the Great Horned Owl,
0:02:27 > 0:02:31and it's this bird I want to put on the Deadly 60.
0:02:31 > 0:02:33Just from this owl calling,
0:02:33 > 0:02:36one of them has come and landed over there.
0:02:36 > 0:02:39And there's actually another one coming in to join it now.
0:02:39 > 0:02:41It's a Harris Hawk.
0:02:43 > 0:02:45They're one of the most common birds of prey here
0:02:45 > 0:02:49and the absolute sworn enemy of the Great Horned Owl.
0:02:49 > 0:02:51Look at this!
0:02:51 > 0:02:54Look at our lady here. She's absolutely fixed on them.
0:02:56 > 0:03:01This is one of the most profound hatreds you'll find
0:03:01 > 0:03:03in the whole of the Sonoran Desert.
0:03:03 > 0:03:08At night-time, the Great Horned Owl will take on, catch and kill a Harris Hawk.
0:03:08 > 0:03:12But in the day, Harris Hawks have something remarkable on their side.
0:03:12 > 0:03:14- They work together as a team. - SCREECH
0:03:14 > 0:03:18And there's two of them sat in the trees right behind me
0:03:18 > 0:03:21watching this little lady.
0:03:21 > 0:03:24They're probably thinking about ganging up on her.
0:03:24 > 0:03:27'Harris Hawks may have the standard issue for birds of prey -
0:03:27 > 0:03:30'they've got lethal talons, razor-sharp beaks
0:03:30 > 0:03:32'and a fast, powerful strike.
0:03:32 > 0:03:35'But weapons aren't everything.
0:03:36 > 0:03:39'These guys have another trick up their sleeves
0:03:39 > 0:03:44'which truly warrants them a place on my Deadly 60.
0:03:47 > 0:03:51'Time to take a closer look at this incredible bird.'
0:03:51 > 0:03:53Look at that!
0:03:53 > 0:03:55Isn't that magnificent?
0:03:55 > 0:03:58Obviously this isn't a wild Harris Hawk.
0:03:58 > 0:04:01You'd never get one of those to fly onto your fist like this.
0:04:01 > 0:04:03This is a falconry bird,
0:04:03 > 0:04:05and this is the absolute classic hawk shape.
0:04:05 > 0:04:09In fact, as she came in to land on my fist, what you'd have seen
0:04:09 > 0:04:12is pretty much exactly the last thing a small mammal would see
0:04:12 > 0:04:14before meeting its end.
0:04:14 > 0:04:18The way she stopped, throwing her wings back, spreading her tail,
0:04:18 > 0:04:22stopped her almost instantly from flight at probably 30, maybe 40mph.
0:04:22 > 0:04:25But the most remarkable thing about this bird of prey
0:04:25 > 0:04:29is that, while most birds of prey tend to be solitary,
0:04:29 > 0:04:31Harris Hawks are very social animals.
0:04:31 > 0:04:34In fact, they hunt with their friends.
0:04:35 > 0:04:40'Like all good teams, each player has got a job to do.
0:04:40 > 0:04:44'We've got a little experiment to show this deadly squad in action.'
0:04:46 > 0:04:48So, we have...
0:04:48 > 0:04:55one, two, three Harris Hawks, all primed and ready.
0:04:55 > 0:04:58Now let's see if we can show you them hunting.
0:05:00 > 0:05:04I've got this leather lure, which they're trained to chase,
0:05:04 > 0:05:06and I'm gonna hide it in here.
0:05:06 > 0:05:11They'll still see it. They have, after all, got "eyes like a hawk".
0:05:11 > 0:05:14We'll see what happens.
0:05:14 > 0:05:18I'm gonna get as far away as humanly possible.
0:05:18 > 0:05:19OK.
0:05:27 > 0:05:29There you go.
0:05:29 > 0:05:31Agh! They're all going for me!
0:05:31 > 0:05:34'Bird one is the frontrunner,
0:05:34 > 0:05:35'flushing the prey from cover,
0:05:35 > 0:05:39'setting up the kill for the next two.'
0:05:39 > 0:05:41And bam! In they go together.
0:05:41 > 0:05:45All three birds hit that lure within a couple of seconds.
0:05:45 > 0:05:49Imagine if you were a rabbit being hit by not just one bird of death, but three!
0:05:49 > 0:05:52You wouldn't stand a chance.
0:05:52 > 0:05:54Now they should,
0:05:54 > 0:05:56if things go to plan,
0:05:58 > 0:06:00share the food a bit.
0:06:00 > 0:06:03Come on, guys! Leave some for your friends.
0:06:03 > 0:06:05SCREECHING
0:06:05 > 0:06:09Scientists believe that when Harris Hawks work together as a group,
0:06:09 > 0:06:12they're more than twice as effective at catching prey
0:06:12 > 0:06:14than on their own.
0:06:14 > 0:06:18For that reason alone, the Harris Hawk makes it onto the Deadly 60.
0:06:18 > 0:06:21SCREECHING
0:06:22 > 0:06:24'Speed, agility and lethal talons
0:06:24 > 0:06:27'are always on hand with birds of prey.
0:06:27 > 0:06:29'But it's their precision teamwork
0:06:29 > 0:06:32'that gets the Harris Hawk onto the Deadly 60.'
0:06:40 > 0:06:42'It's close to midday and temperatures are soaring,
0:06:42 > 0:06:44'but we're on the road again
0:06:44 > 0:06:48'on the search for our next deadly animal.'
0:06:50 > 0:06:53This is the extreme south of the Sonoran Desert.
0:06:53 > 0:06:57If I kept going in that direction for 10-15 miles, I'd be in Mexico.
0:06:57 > 0:07:00It's a real, full-on, rocky wilderness.
0:07:00 > 0:07:04Perfect habitat for the magnificent big cat we're hoping to find.
0:07:04 > 0:07:07It's found throughout North and South America
0:07:07 > 0:07:09and goes by many different names:
0:07:09 > 0:07:11the puma, the cougar,
0:07:11 > 0:07:13and here, the mountain lion.
0:07:14 > 0:07:17'Mountain lions are such secretive creatures
0:07:17 > 0:07:20'that to see one hunting is almost unheard of.
0:07:20 > 0:07:23'Just catching a glimpse of one during the day is a privilege.
0:07:23 > 0:07:25'So how do we know they're deadly?
0:07:25 > 0:07:30'Well, firstly, by looking at their closest cousins.
0:07:32 > 0:07:36'And secondly, by the evidence they leave from their deadly deeds,
0:07:36 > 0:07:38'taking livestock, deer,
0:07:38 > 0:07:41'even attacking the odd person.
0:07:41 > 0:07:45'Their secretive ways certainly won't make them any easier to find.
0:07:50 > 0:07:53'We're heading deep into one of the many canyons found here.
0:07:53 > 0:07:59'My guide is Emil, who's an expert at tracking the mountain lion.'
0:07:59 > 0:08:04These tight canyon walls really help focus the cat's movements
0:08:04 > 0:08:08into a narrow and predictable spot.
0:08:08 > 0:08:12And that's the kind of place we're looking for to set a trail camera,
0:08:12 > 0:08:17where everything moving through this canyon has to pass.
0:08:17 > 0:08:22This just could not be more classic mountain lion territory.
0:08:22 > 0:08:26Just imagine seeing a cat wander out over those rocks.
0:08:26 > 0:08:28Fingers crossed.
0:08:33 > 0:08:37'Emil works on a project that records and studies the lions in this area.
0:08:37 > 0:08:41'And they do this using some very clever camera technology.
0:08:41 > 0:08:45'Cameras are hidden and take a picture of anything that moves in front of it.
0:08:45 > 0:08:48'The question is: Has it captured an image of a mountain lion?'
0:08:48 > 0:08:50Let's see what we got.
0:08:52 > 0:08:55This is an infrared flash,
0:08:55 > 0:08:58and it's actually taking a video clip
0:08:58 > 0:09:01immediately after the photograph is taken.
0:09:01 > 0:09:04- What is that?- Peccary.- No.
0:09:04 > 0:09:07- It's not a razorback, is it? - It's a black bear.
0:09:07 > 0:09:09No!
0:09:09 > 0:09:12- A nice, big, beautiful black bear. - Wow!
0:09:12 > 0:09:14What a great shot!
0:09:14 > 0:09:18Oh, there's the Coues deer, the white-tailed deer.
0:09:21 > 0:09:23- Argh!- There he is.
0:09:23 > 0:09:26Fantastic! Look at that!
0:09:26 > 0:09:28Look at that beautiful cat.
0:09:28 > 0:09:31Oh, that is absolutely wonderful!
0:09:31 > 0:09:33This animal ran through
0:09:33 > 0:09:37- right where I'm sitting now. - Exactly where we're sitting, yeah.
0:09:37 > 0:09:39EMIL CHUCKLES
0:09:39 > 0:09:41- Wow!- Do you know what that is?
0:09:41 > 0:09:44It looks like... I'm not gonna say. It looks like a cat
0:09:44 > 0:09:48- just coming right down towards the front of the lens.- Absolutely.
0:09:48 > 0:09:51Unfortunately the face is just out of the frame.
0:09:51 > 0:09:56- But it'll be on the video. - We'll have a video of this one.
0:09:56 > 0:09:59Oh! Look at that!
0:09:59 > 0:10:02- Wonderful!- All right.
0:10:02 > 0:10:04EMIL CHUCKLES
0:10:04 > 0:10:09And she was here at 3:20 in the afternoon.
0:10:09 > 0:10:12- Broad daylight. - It's quarter to three right now.
0:10:12 > 0:10:16Well, if we sit here long enough, you never know.
0:10:16 > 0:10:18If we sit here long enough, one will walk by.
0:10:18 > 0:10:21- Well, we saw a couple of lions. - Great stuff!
0:10:21 > 0:10:23That's absolutely fantastic!
0:10:23 > 0:10:26Can you believe they were walking here in the middle of the day?
0:10:26 > 0:10:28Yeah, now that I'd like to see.
0:10:30 > 0:10:32PURRING
0:10:33 > 0:10:37Our mission to find a mountain lion has taken a really exciting twist.
0:10:37 > 0:10:40Local biologists have tracked one particular mountain lion
0:10:40 > 0:10:43that's been ranging through hundreds of miles of mountains.
0:10:43 > 0:10:46But today they've got to try and capture it.
0:10:46 > 0:10:51This could be our perfect opportunity to get right up close to a mountain lion.
0:10:51 > 0:10:55'The scientists want to catch the lion to remove a tracking collar
0:10:55 > 0:11:01'holding information about its movements for the last six months.'
0:11:01 > 0:11:05All this modern technology, and our best chance of finding a lion
0:11:05 > 0:11:07is old-fashioned tracking.
0:11:07 > 0:11:11These dogs have been trained to pick up the scent of a mountain lion.
0:11:11 > 0:11:15They're wearing GPS collars so we know exactly where they go.
0:11:15 > 0:11:19With a bit of luck, they'll lead us straight to the lion.
0:11:19 > 0:11:22They're looking very excited.
0:11:22 > 0:11:23Good luck, guys!
0:11:23 > 0:11:26'These sniffer dogs will follow the scent of the lion,
0:11:26 > 0:11:29'and, like a domestic cat avoiding a dog,
0:11:29 > 0:11:33'the lion will climb a tree when they get close.
0:11:33 > 0:11:35'The dogs will then wait at the base of the tree
0:11:35 > 0:11:38'until the scientists arrive to capture the animal.
0:11:38 > 0:11:41'Without the dogs, the lion would just keep running
0:11:41 > 0:11:45'and the team wouldn't stand a chance of getting near it.
0:11:50 > 0:11:53'A mountain lion could cover a huge area in search of food -
0:11:53 > 0:11:56'up to 100 square miles.
0:11:56 > 0:11:58'And in this kind of habitat,
0:11:58 > 0:12:01'that's a whole lot of holes to hide in.'
0:12:04 > 0:12:06VOICES OVER RADIO
0:12:06 > 0:12:08Just had the most amazing call on the radio.
0:12:08 > 0:12:11The guys with the hounds have located the lion.
0:12:11 > 0:12:15They think it's coming down the dry river bed we're on now, right towards us.
0:12:15 > 0:12:18VOICES OVER RADIO
0:12:21 > 0:12:23It's all going off on the rocks ahead of us.
0:12:23 > 0:12:26- DOGS BARKING - The dogs are going mad.
0:12:26 > 0:12:30It looks like the lion's gone into a hole somewhere in these rocks.
0:12:32 > 0:12:35VOICES OVER RADIO
0:12:45 > 0:12:46DOGS HOWL
0:12:46 > 0:12:49Where do we think the lion is?
0:12:49 > 0:12:51- This hole right here. - We can't get up.
0:12:51 > 0:12:54We're trying to get up in there and look in.
0:12:54 > 0:12:56'There's only one thing to do:
0:12:56 > 0:12:58'in order to see if there's a lion up there,
0:12:58 > 0:13:01'I'll have to climb up very carefully
0:13:01 > 0:13:03'and have a closer look.'
0:13:10 > 0:13:13- Can you see the end of it? - Well...
0:13:13 > 0:13:18There definitely has been a cat in here very recently.
0:13:18 > 0:13:22Steve, does that thing go on back up in there or not?
0:13:22 > 0:13:25No. Doesn't seem to.
0:13:26 > 0:13:27It stops here.
0:13:32 > 0:13:34All of a sudden, with everything going crazy
0:13:34 > 0:13:39and us being certain that we had our mountain lion,
0:13:39 > 0:13:41total silence.
0:13:41 > 0:13:43The trail's gone cold.
0:13:43 > 0:13:48It seems like the cat's managed to get out of the canyon and head off into the distance,
0:13:48 > 0:13:52so our chances of finding it now are slim to none.
0:13:52 > 0:13:54But we came this close.
0:13:55 > 0:13:58Anyway, despite the fact that we didn't quite make it,
0:13:58 > 0:14:04there has to be no doubt that a cat this beautiful that manages to range throughout the Americas
0:14:04 > 0:14:06so strong, so powerful,
0:14:06 > 0:14:07it's got to be on the Deadly 60.
0:14:09 > 0:14:12'Whether we've seen one in the flesh or not,
0:14:12 > 0:14:13'this awesome predator,
0:14:13 > 0:14:19'capable of avoiding dogs, horses, trackers, and this camera crew,
0:14:19 > 0:14:23'has certainly got to go on the Deadly 60.'
0:14:28 > 0:14:33Despite what many people think about deserts being alive with snakes,
0:14:33 > 0:14:39they can be quite shy of people and often very hard to find.
0:14:39 > 0:14:43Luckily, though, we've got some Deadly 60 technology on our side.
0:14:45 > 0:14:47Matt, talk us through how this works.
0:14:47 > 0:14:49This antenna's directional,
0:14:49 > 0:14:53so it'll tell you the strongest signals where the snake is.
0:14:53 > 0:14:56- So if you listen, you can... - BLEEPS
0:15:03 > 0:15:07- It's a little louder that way. - It does seem stronger in that direction.
0:15:07 > 0:15:09Perfect. I'm following you.
0:15:09 > 0:15:14I should point out that this isn't just a magic snake-finding device.
0:15:14 > 0:15:17All the animals we'll be looking for have been caught
0:15:17 > 0:15:19and implanted with a radio transmitter
0:15:19 > 0:15:22about the size of my little finger.
0:15:22 > 0:15:24That's the signal we're trying to pick up now.
0:15:25 > 0:15:28'So this is what we're looking for.
0:15:28 > 0:15:32'Rattlesnakes are the classic desert predator,
0:15:32 > 0:15:35'arguably the most sophisticated snake on the planet,
0:15:35 > 0:15:39'with hinged fangs, a superfast strike
0:15:39 > 0:15:42'and an amazing sense of smell.
0:15:43 > 0:15:47'This is the animal most people try and avoid.
0:15:51 > 0:15:55'Even with this technology, it won't be easy finding a rattler,
0:15:55 > 0:15:59'and with the temperature soaring to over 35 degrees,
0:15:59 > 0:16:02'the crew are really having to work hard.
0:16:04 > 0:16:06'Matt's picked up a signal,
0:16:06 > 0:16:08'but it isn't coming from a rattlesnake.'
0:16:08 > 0:16:11- Sounds pretty strong. - Yeah. Here and a bit further.
0:16:11 > 0:16:14It sounds like it's right under my feet in some way.
0:16:14 > 0:16:16Yeah, we're very close.
0:16:16 > 0:16:20'It's a Gila monster, an animal I've never seen up close before.
0:16:20 > 0:16:23'If we can catch it, it'll be a real bonus
0:16:23 > 0:16:26'and a true contender for a place on the Deadly 60.
0:16:30 > 0:16:32'Now I've got to be extra careful here
0:16:32 > 0:16:34'as one bite could put me in hospital.'
0:16:38 > 0:16:40Oh, yeah, here it is, right here.
0:16:40 > 0:16:43- Got it, got it, got it.- Well done!
0:16:45 > 0:16:48- Oh, wow!- She's right there, right?
0:16:48 > 0:16:51OK.
0:16:51 > 0:16:52This is gonna be awkward.
0:16:52 > 0:16:55- I might go up there.- Go around.
0:16:55 > 0:16:59She will try to get away real quick if you're not careful.
0:16:59 > 0:17:03Just don't get your hands anywhere near that mouth.
0:17:04 > 0:17:06Got her by the tail.
0:17:06 > 0:17:09- Bring her out gently.- OK.
0:17:10 > 0:17:12Oh, wow!
0:17:12 > 0:17:15Now if you can get behind the neck.
0:17:15 > 0:17:18STEVE GRUNTS
0:17:23 > 0:17:25- There you go.- Fabulous!
0:17:25 > 0:17:27Absolutely fabulous!
0:17:27 > 0:17:31Well, this wasn't what we came out here looking for,
0:17:31 > 0:17:35but this is a creature which is definitely worthy of the Deadly 60.
0:17:35 > 0:17:39Matt, this is the first Gila monster I've ever seen!
0:17:39 > 0:17:41- Right on.- Great job! Absolutely wonderful!
0:17:41 > 0:17:43- Incredible, aren't they?- Yeah.
0:17:43 > 0:17:48That is an absolutely beautiful creature.
0:17:49 > 0:17:53'Unlike rattlesnakes, Gila monster venom attacks the nervous system
0:17:53 > 0:17:55'and stops their prey breathing.
0:17:55 > 0:18:00'Luckily, it isn't usually fatal to humans, but it's famously painful.
0:18:03 > 0:18:06'Gila monsters eat small birds, mammals and lizards.
0:18:06 > 0:18:09'But their favourite food are bird and reptile eggs.
0:18:09 > 0:18:13'Its fantastic sense of smell helps it locate its prey.
0:18:13 > 0:18:16'It's said that a Gila can follow the trail of an egg
0:18:16 > 0:18:18'rolled along the ground.'
0:18:20 > 0:18:22They're almost preposterous-looking creatures.
0:18:22 > 0:18:25The head looks like a dinosaur.
0:18:25 > 0:18:29This thick tail is full of fat.
0:18:29 > 0:18:32These are sort of storage of energy
0:18:32 > 0:18:35which they can use, I guess, when hibernating in winter.
0:18:35 > 0:18:39Look at these claws, almost like a bird of prey's talons,
0:18:39 > 0:18:42perfect for digging and scrabbling around in the dirt.
0:18:42 > 0:18:46But the head really is the business part of the Gila monster.
0:18:46 > 0:18:49You can see it's fat and blocky, really sturdy,
0:18:49 > 0:18:53got really positive muscles for driving heavy jaws.
0:18:53 > 0:18:56And it's set up a bit like a pit bull terrier.
0:18:56 > 0:18:58When they get ahold of you, they don't let go.
0:18:58 > 0:19:01What they're actually doing with that bite
0:19:01 > 0:19:03is allowing saliva to drip down onto their teeth
0:19:03 > 0:19:06and actually get chewed into the wound,
0:19:06 > 0:19:08and that venom is pretty potent.
0:19:08 > 0:19:10It would certainly give me a nasty shock.
0:19:10 > 0:19:13They're one of the only venomous lizards in the world.
0:19:13 > 0:19:17That alone should give the Gila monster a place on the Deadly 60.
0:19:19 > 0:19:22'Squat, slow and... well, a bit strange,
0:19:22 > 0:19:25'it's not a typical Deadly 60 candidate.
0:19:25 > 0:19:28'But being one of the only lizards in the world with a venomous bite
0:19:28 > 0:19:32'gets the Gila monster on the Deadly 60.
0:19:37 > 0:19:39'While we sweat it out on the search,
0:19:39 > 0:19:41'take a look at the demo me and the crew did
0:19:41 > 0:19:46'to show you how the rattlesnake is such an effective killer.
0:19:46 > 0:19:50'But to do this, we need to turn the lights out.'
0:19:51 > 0:19:53This is a thermal imaging camera.
0:19:53 > 0:19:58It actually picks up the heat generated by objects around you.
0:19:58 > 0:20:01So things like...
0:20:01 > 0:20:04this cactus here.
0:20:04 > 0:20:07Obviously cactus have an awful lot of water in them,
0:20:07 > 0:20:09and all that water is still quite warm,
0:20:09 > 0:20:12so the cactus stands out beautifully
0:20:12 > 0:20:14against the black of the sky.
0:20:14 > 0:20:17And if I turn this onto the camera crew...
0:20:17 > 0:20:20And Johnny, the cameraman,
0:20:20 > 0:20:22the camera's dark,
0:20:22 > 0:20:25and his head is almost white.
0:20:25 > 0:20:28So, got a foxy bit of kit. Let's go see what we can find.
0:20:33 > 0:20:36'This detection of heat is exactly how a rattlesnake
0:20:36 > 0:20:39'is able to see its prey in the dark.
0:20:39 > 0:20:41'It has supersensitive heat sensors
0:20:41 > 0:20:45'on its face that pick up the heat given off from its prey's body,
0:20:45 > 0:20:48'allowing the snake to catch its supper
0:20:48 > 0:20:50'in the pitch black of night.'
0:20:52 > 0:20:57A good-sized rat is eyeing me up from the rocks in front of me.
0:20:57 > 0:21:00You can see the warmth generated by his body heat.
0:21:00 > 0:21:03His eyes, particularly, seem to be very hot.
0:21:12 > 0:21:16I'm being watched very intently
0:21:16 > 0:21:18from no more than about ten feet away,
0:21:18 > 0:21:22by a very bright pair of yellow eyes.
0:21:23 > 0:21:26This is an Elf Owl.
0:21:26 > 0:21:28He's probably...
0:21:28 > 0:21:32no more than about that high, I'm guessing.
0:21:32 > 0:21:35He is beautiful.
0:21:35 > 0:21:38'This is exactly what a rattlesnake would see
0:21:38 > 0:21:39'if it was looking at this owl.
0:21:43 > 0:21:49'Now let's turn the lights back on and see if we can find one.'
0:21:54 > 0:21:56Ow!
0:22:01 > 0:22:05Some of these cactus could be well over 100 years old.
0:22:05 > 0:22:08Even older than Nick, our sound man.
0:22:09 > 0:22:12STEVE LAUGHS
0:22:15 > 0:22:20There's a lot of reasons why reptiles do so well in dry desert environments like this.
0:22:20 > 0:22:22Firstly, being so-called cold-blooded,
0:22:22 > 0:22:26they get their energy from the sun, and there's plenty of that here.
0:22:26 > 0:22:29Also, they have remarkable watertight skin,
0:22:29 > 0:22:33so they don't sweat or use any water from the outside environment.
0:22:33 > 0:22:36They have the ability, in times when there's not much food around,
0:22:36 > 0:22:39to just lie around and do nothing,
0:22:39 > 0:22:41and, in extreme cases, even hibernate.
0:22:43 > 0:22:46Oh! Look what you just stepped over.
0:22:46 > 0:22:48- Oh, my goodness. - Johnny, look at this.
0:22:48 > 0:22:53Well! We're out looking for reptiles...
0:22:53 > 0:22:55but this one wasn't on our minds.
0:22:55 > 0:22:58It's a deadly tortoise.
0:22:58 > 0:23:02- Matt, what species is this? - That'd be the Desert Tortoise.
0:23:02 > 0:23:06- I guess it's called that because it lives in the desert.- Yeah.
0:23:06 > 0:23:08THEY LAUGH
0:23:08 > 0:23:13- Those things do a good impression of a rock.- They certainly do.
0:23:13 > 0:23:17The Desert Tortoise has a way of dealing with heat and predators.
0:23:17 > 0:23:19It doesn't need to hide in the rocks.
0:23:19 > 0:23:23It takes its own home and protection along with it.
0:23:23 > 0:23:25Great stuff.
0:23:36 > 0:23:38That one is a snake.
0:23:38 > 0:23:41'Matt's locked on to a signal from a rattlesnake.
0:23:41 > 0:23:46'We're getting close and we need to be really careful where we tread.'
0:23:50 > 0:23:52- Where?- You see him?
0:23:52 > 0:23:55OK, he's right there? Good.
0:24:00 > 0:24:01Perfect.
0:24:03 > 0:24:06If you can get him on the first shot, that's good.
0:24:06 > 0:24:09One fell swoop.
0:24:11 > 0:24:13Come around the other side now.
0:24:13 > 0:24:16RATTLING
0:24:16 > 0:24:18Listen to that!
0:24:18 > 0:24:24That is THE sound of the Sonoran Desert.
0:24:25 > 0:24:27RATTLING
0:24:32 > 0:24:35Let's get him out in the open where we can look at him.
0:24:37 > 0:24:39RATTLING
0:24:40 > 0:24:42Listen to that rattle!
0:24:45 > 0:24:47LOUD RATTLING
0:24:47 > 0:24:52That wonderful sound is really the signature sound of the desert.
0:24:52 > 0:24:54You hear it in all the Western movies.
0:24:56 > 0:24:59Interlocking segments of keratin,
0:24:59 > 0:25:02the same substance that's in our fingernails,
0:25:02 > 0:25:06rattle together and create that incredible buzzing sound.
0:25:07 > 0:25:11'Matt's marked the wild snakes he's studying with some paint
0:25:11 > 0:25:13so he can identify them.'
0:25:14 > 0:25:18This is a tiger rattlesnake.
0:25:18 > 0:25:21The dark and light bands running across the body
0:25:21 > 0:25:24are for camouflage and are what give it its name.
0:25:25 > 0:25:30These tongs look like they're squashing the snake, but it's a resilient creature.
0:25:30 > 0:25:33They're not doing it any harm at all.
0:25:33 > 0:25:38It's not a particularly big snake, but it does have very potent venom.
0:25:38 > 0:25:41Certainly enough to mean I have to be very wary of it.
0:25:41 > 0:25:43What a beauty!
0:25:43 > 0:25:47Actually, what this is is an incredible predator.
0:25:47 > 0:25:49The reason for that is a supersense.
0:25:49 > 0:25:51Looking at the front of the head,
0:25:51 > 0:25:55the snake almost appears to have two sets of nostrils.
0:25:55 > 0:25:59The lower ones are what's called a loreal pit,
0:25:59 > 0:26:03which picks up the warmth generated by the moving muscles of its prey.
0:26:03 > 0:26:07It can literally see animals moving in the dark.
0:26:08 > 0:26:12'Exactly as we saw earlier with our thermal camera.'
0:26:14 > 0:26:17So all it has to do is to sit and wait
0:26:17 > 0:26:21for a small mouse or other warm-blooded mammal to walk too close by,
0:26:21 > 0:26:24and then it'll strike with its potent venom.
0:26:24 > 0:26:28First of all, it instantly starts to slow the prey down.
0:26:32 > 0:26:35But the prey also starts to bleed internally
0:26:35 > 0:26:37and to urinate as it runs away,
0:26:37 > 0:26:41leaving a scent trail which the rattlesnake can follow.
0:26:42 > 0:26:45'So, dangerous to us they may be,
0:26:45 > 0:26:47'but the rattlesnake is going on the Deadly 60
0:26:47 > 0:26:53'because of its ability to track, ambush and immobilise its prey.
0:26:57 > 0:27:00'Venom, speed, supersenses, camouflage,
0:27:00 > 0:27:03'and... did I mention venom?
0:27:03 > 0:27:06'Well, there you go. The rattlesnake.
0:27:10 > 0:27:12'Coming up next time on the Deadly 60:
0:27:23 > 0:27:25Look at that!
0:27:38 > 0:27:40Subtitles by Red Bee Media Ltd
0:27:40 > 0:27:42E-mail subtitling@bbc.co.uk