0:00:02 > 0:00:04# Marauding mice and walls of ice
0:00:04 > 0:00:06# And sharks on a golfing spree!
0:00:06 > 0:00:08# Cicada swarms and martian storms
0:00:08 > 0:00:10# And fish walking out of the sea!
0:00:10 > 0:00:12- # Really?! - Elks in trees and foaming seas
0:00:12 > 0:00:15- # And giant mayfly mobs! - Huh?!
0:00:15 > 0:00:17# Zombie snails and friendly whales
0:00:17 > 0:00:19- # And completely frozen frogs! - You what?!
0:00:19 > 0:00:21# They're wild and weird Wild and weird
0:00:21 > 0:00:23# Really, really wild And really, really weird
0:00:23 > 0:00:26# They're wild and weird Wild and weird
0:00:26 > 0:00:27# They're really, really wild
0:00:27 > 0:00:29# They're really, really wild and weird! #
0:00:29 > 0:00:31Today, it's Super Swarms,
0:00:31 > 0:00:34including the mouse plague that took Australian farmers by storm...
0:00:34 > 0:00:35'They're in my boots!'
0:00:35 > 0:00:39..monarch butterflies in their millions on their Mexican migration,
0:00:39 > 0:00:42and a locust swarm of Biblical proportions.
0:00:51 > 0:00:55Treehouse is all ready for you, Naomi. Just as you requested.
0:00:55 > 0:00:57You'll be as snug as a bug in a rug.
0:00:57 > 0:00:59Whoo!
0:00:59 > 0:01:02- Goodness me, it's roasting in here!- Oh, yeah.
0:01:02 > 0:01:04It's nice, isn't it?
0:01:04 > 0:01:06No, it's like a sauna!
0:01:06 > 0:01:10Well, yeah. I've turned the boiler up, just like you asked.
0:01:10 > 0:01:12- I didn't ask you to do that. - Yeah, you did.
0:01:12 > 0:01:15You said, "Meet me on the sofa and make sure it's warm."
0:01:15 > 0:01:20No, I said, "Meet me on the sofa and make sure it's SWARMS."
0:01:20 > 0:01:23You know, swarms on the TV.
0:01:23 > 0:01:24Oh...
0:01:25 > 0:01:28I'm a bit embarrassed now, actually.
0:01:28 > 0:01:31- Yeah, I might go put some clothes on. - Yeah. Hurry back.- Will do.
0:01:33 > 0:01:37Uh...Tim!
0:01:37 > 0:01:38You'll be needing this.
0:01:38 > 0:01:41Stop looking!
0:01:41 > 0:01:42Saw you laugh, then.
0:01:44 > 0:01:48For our first super swarm, we head to Australia.
0:01:48 > 0:01:49'Picture the scene.
0:01:49 > 0:01:52'It's 1993 on a farm in southern Australia,
0:01:52 > 0:01:53'and a desperate farmer
0:01:53 > 0:01:57'has got something of a mouse problem on her hands.'
0:01:57 > 0:01:59'Yeah, no kidding.'
0:01:59 > 0:02:00They're in my boots!
0:02:02 > 0:02:06'It gets worse. Check out what she does now...'
0:02:06 > 0:02:08'She doesn't go in, does she?'
0:02:08 > 0:02:09Oh, yuck!
0:02:09 > 0:02:11'No! No! Don't go inside!'
0:02:11 > 0:02:12Why would you go inside?
0:02:12 > 0:02:15She has to go in, her pigs are in there.
0:02:15 > 0:02:18'And the mice are so desperate for food
0:02:18 > 0:02:21'they're literally trying to eat her pigs alive.'
0:02:22 > 0:02:25'Fast-forward to 2011
0:02:25 > 0:02:27'and it wasn't much better...'
0:02:27 > 0:02:29New crops have been devoured
0:02:29 > 0:02:33across South Australia, Victoria and Western Australia
0:02:33 > 0:02:36in the worst mouse plague in almost two decades.
0:02:36 > 0:02:39- 'Meet sheep farmer Ian.' - 'Hello, Ian.'
0:02:39 > 0:02:41'As well as feeding all his sheep,
0:02:41 > 0:02:45'he found he was inadvertently feeding millions of tiny mouths,
0:02:45 > 0:02:48'thanks to his massive storage barn of grain.'
0:02:52 > 0:02:56Whoa, whoa. Hang on a minute. Let's just go back a bit...
0:02:56 > 0:02:57'Yeah, look.
0:02:57 > 0:03:02'He's left his barn doors wide open! It's no wonder he's got mice.'
0:03:02 > 0:03:04- Finished?- Yeah.
0:03:04 > 0:03:06I was just stating the obvious.
0:03:07 > 0:03:09Oh!
0:03:09 > 0:03:10We've tried poisoning them,
0:03:10 > 0:03:13we've tried all sorts to try and cut their numbers.
0:03:13 > 0:03:15Over here, quick!
0:03:17 > 0:03:19'No way!'
0:03:19 > 0:03:21'Way.'
0:03:25 > 0:03:27Nothing works.
0:03:27 > 0:03:29OK, here are the stats.
0:03:29 > 0:03:32A mouse eats up to a third of its body weight every day,
0:03:32 > 0:03:34that's about eight grams.
0:03:34 > 0:03:38Multiply that by the estimated half-a-million-plus mice
0:03:38 > 0:03:42which are living on Ian's farm, and they could consume...
0:03:42 > 0:03:47Whoa, whoa! Don't tell me, don't tell me. Seeing if I'm still sharp up top.
0:03:47 > 0:03:49Right, 500,000 mice...
0:03:49 > 0:03:51The grain, well, they can consume eight grams a day.
0:03:51 > 0:03:53That's what you said. So, 500,000...
0:03:53 > 0:03:57OK, yes. Ha-ha!
0:03:58 > 0:04:03- Lots of it.- Thanks, Tim. I don't know what I would do without you.
0:04:03 > 0:04:05Or Greg, for that matter.
0:04:05 > 0:04:08WHISPERS: Who's Greg?
0:04:08 > 0:04:10He's been studying Australia's mouse plagues,
0:04:10 > 0:04:13and he's noticed something pretty unusual.
0:04:13 > 0:04:15He goes out of focus before he talks?
0:04:15 > 0:04:17The strange things about house mice is that,
0:04:17 > 0:04:21although they've got almost a global distribution now,
0:04:21 > 0:04:24the only places where they cause these massive mouse plagues
0:04:24 > 0:04:28appear to be in Australia and in Western China.
0:04:28 > 0:04:30- I tell you what the Aussies need.- What?
0:04:30 > 0:04:34- Couple of good old-fashioned mice-munching predators.- Precisely.
0:04:34 > 0:04:37And that's the problem.
0:04:37 > 0:04:40In Australia, mice have few natural predators
0:04:40 > 0:04:44and the local kangaroos and koalas are no competition whatsoever.
0:04:44 > 0:04:49- So, when conditions are right, nothing can stop them.- Hmm.
0:04:49 > 0:04:52Except for one man I know...
0:04:53 > 0:04:56PHONE RINGS Bear with me.
0:04:56 > 0:04:58Hello, mate. It's Tim.
0:04:58 > 0:05:00- How you doing, PP?- Who's PP?
0:05:00 > 0:05:02Pied Piper.
0:05:02 > 0:05:06Listen, bit of a problem in Oz - you available?
0:05:06 > 0:05:08Ah. Really?
0:05:08 > 0:05:11- That's a shame. Still in Hamelin.- Aw.- Yeah.
0:05:11 > 0:05:13All right, mate, not to worry.
0:05:13 > 0:05:16Yeah. Cheers, then. Bye-bye. Bye-bye.
0:05:16 > 0:05:19Those rats, they'll be the death of him.
0:05:19 > 0:05:21- Are you ready for our next super swarm?- Yeah! Go on.
0:05:21 > 0:05:24- Where are we off to?- Mexico.
0:05:24 > 0:05:26Mexico!
0:05:26 > 0:05:27Hold there one second.
0:05:27 > 0:05:29CLOCK TICKS
0:05:29 > 0:05:31Sorry about this.
0:05:33 > 0:05:36Yeah. All right.
0:05:36 > 0:05:38I am ready. Arriba!
0:05:39 > 0:05:41'In early October 2011,
0:05:41 > 0:05:46'the Denning family were hiking through woodland in central Mexico
0:05:46 > 0:05:50'when they became part of one of the most extraordinary events
0:05:50 > 0:05:51'in the natural world.'
0:05:52 > 0:05:55Look at them all! Do you see that, guys?
0:05:57 > 0:06:00- 'A multitude of monarch butterflies.'- Wow!
0:06:00 > 0:06:04'A vision in orange, carpeting small stands of pines.'
0:06:04 > 0:06:07'I bet he's thinking how awesome that is.'
0:06:07 > 0:06:10This is awesome.
0:06:10 > 0:06:11'Ha-ha! Told you.'
0:06:14 > 0:06:18Hard to believe just days before these trees would have been bare.
0:06:19 > 0:06:23So, where have all these swathes of butterflies come from,
0:06:23 > 0:06:24I hear you ask?
0:06:24 > 0:06:26I didn't ask, but, yeah, I'd like to know.
0:06:26 > 0:06:28And why are they here?
0:06:28 > 0:06:30Again, I didn't ask,
0:06:30 > 0:06:32but I am pretty curious now.
0:06:33 > 0:06:35If only there was - I don't know -
0:06:35 > 0:06:38a butterfly expert to help fill in all the blanks...
0:06:38 > 0:06:42- There is! Richard Fox.- Brilliant.
0:06:42 > 0:06:47He's spent years studying the intricacies of butterfly behaviour.
0:06:49 > 0:06:51Basically, it's too cold in the wintertime
0:06:51 > 0:06:53across most of the United States,
0:06:53 > 0:06:57and certainly in Canada, for these butterflies to survive.
0:06:57 > 0:06:59So they've got to move or die.
0:06:59 > 0:07:01Ah!
0:07:01 > 0:07:04So the monarchs are quite literally flying for their lives
0:07:04 > 0:07:07away from the cold North, where they usually live.
0:07:07 > 0:07:10Yep, and it's a seriously long-haul flight.
0:07:10 > 0:07:14Starting in Canada, these butterflies cover over 2,000 miles
0:07:14 > 0:07:18and fly for anything up to 10 weeks to reach these winter roosts.
0:07:18 > 0:07:21That is INSANE.
0:07:21 > 0:07:23They must have a MASSIVE brain.
0:07:23 > 0:07:27- They have a brain the size of a pinhead.- Well, that's his opinion.
0:07:27 > 0:07:31And yet they're able to navigate across a continent.
0:07:31 > 0:07:33Which is remarkable when you think about it,
0:07:33 > 0:07:36- because you have got a brain the size of an orange...- Thank you.
0:07:36 > 0:07:40- ..and yet you can't find your way to the shower.- Yes, I can!
0:07:40 > 0:07:42HE SNIFFS HIMSELF
0:07:44 > 0:07:47And they're not flying blind.
0:07:47 > 0:07:50Monarchs come equipped with some serious in-built sat nav.
0:07:52 > 0:07:56In their brains they have a compass,
0:07:56 > 0:08:01which uses sunshine as a way of working out north and south.
0:08:01 > 0:08:04And in their antennae, their feelers,
0:08:04 > 0:08:06they have a clock
0:08:06 > 0:08:09which enables them to take account
0:08:09 > 0:08:11for the passage of the sun across the sky.
0:08:14 > 0:08:15As they travel further south,
0:08:15 > 0:08:19monarchs from all over the United States are funnelled together
0:08:19 > 0:08:22by the Gulf Coast and the Rocky Mountains.
0:08:22 > 0:08:24In a good year, I reckon that could be the best part
0:08:24 > 0:08:26of a million monarchs.
0:08:26 > 0:08:30In a good year it might be 150 million monarchs.
0:08:30 > 0:08:33Erm...OK. Move on.
0:08:33 > 0:08:34With so many butterflies,
0:08:34 > 0:08:37it literally becomes an orange explosion.
0:08:38 > 0:08:40Speaking of orange explosions...
0:08:42 > 0:08:44DYNAMITE BOOMS
0:08:46 > 0:08:49I will not be trying that again. Hang on... What?
0:08:49 > 0:08:52Do you want to go back to Australia for our final super swarm?
0:08:52 > 0:08:54Yeah, let's do that.
0:08:55 > 0:08:58In 2010, the country was hit by a plague
0:08:58 > 0:09:01which was both uncontrollable and unstoppable.
0:09:03 > 0:09:04LAUGHTER
0:09:04 > 0:09:08Ow, ow, ow, ow!
0:09:10 > 0:09:11Hang on one second...
0:09:12 > 0:09:16Never, ever go to Australia.
0:09:18 > 0:09:21Yeah. Sorry about that. OK.
0:09:21 > 0:09:24Oww!
0:09:24 > 0:09:28At this primary school near the outback town of Mildura,
0:09:28 > 0:09:31the kids were enjoying their playtime when the swarm hit.
0:09:32 > 0:09:35There were millions.
0:09:35 > 0:09:37Billions.
0:09:37 > 0:09:39Quite a lot of them.
0:09:39 > 0:09:41It just felt disgusting.
0:09:41 > 0:09:45Mostly all the girls were just going, "Ah!"
0:09:45 > 0:09:48See, on their own, they don't look too scary, do they?
0:09:48 > 0:09:51HE SCREAMS
0:09:51 > 0:09:54It's just like that lad said. You big wuss!
0:09:54 > 0:09:56Why would you do that?
0:09:58 > 0:10:00But whilst the locusts were causing chaos in the town,
0:10:00 > 0:10:04it was altogether more serious out amongst the farms.
0:10:04 > 0:10:06Here, the locusts were not just an inconvenience,
0:10:06 > 0:10:09they were a devastating force.
0:10:11 > 0:10:15Professor Simpson is one of the world's leading experts on locusts,
0:10:15 > 0:10:18and knows all about their destructive power.
0:10:18 > 0:10:22They eat, each day, about their own body weight in food.
0:10:22 > 0:10:25And in the interest of scientific experiments,
0:10:25 > 0:10:28- that would be like you eating all of these doughnuts.- What's that?
0:10:28 > 0:10:32I've got to eat all these doughnuts?! Ha! Anything for you.
0:10:32 > 0:10:33Mmm.
0:10:33 > 0:10:35Oh.
0:10:35 > 0:10:37It's a big one. Mm!
0:10:37 > 0:10:40And when you multiply that single locust
0:10:40 > 0:10:43by hundreds of millions, or billions,
0:10:43 > 0:10:47you can get the sort of devastation that we've seen.
0:10:47 > 0:10:49But what's really weird about locusts
0:10:49 > 0:10:54is that they all start life as a harmless little grasshopper.
0:10:54 > 0:10:57One who shuns company and prefers a solitary life.
0:10:58 > 0:11:01Aww! All alone.
0:11:01 > 0:11:04So what could possibly change them from a shy singleton
0:11:04 > 0:11:07into a voracious, gregarious plague insect?
0:11:07 > 0:11:08I bet the prof knows.
0:11:13 > 0:11:17When they get brought together by food and their environment,
0:11:17 > 0:11:20they flip from being shy, solitary animals
0:11:20 > 0:11:24into being actively aggregating, potentially swarm-forming creatures.
0:11:26 > 0:11:27The prof had a theory
0:11:27 > 0:11:29that it was something to do with
0:11:29 > 0:11:31being in close contact with other locusts,
0:11:31 > 0:11:35and so they set about testing this theory in a rather unusual way.
0:11:37 > 0:11:38You know, I'd imagine
0:11:38 > 0:11:41that with an epidemic of this proportion on their hands,
0:11:41 > 0:11:43the experts are working around the clock
0:11:43 > 0:11:46to come with some real hi-tech solution to all this.
0:11:47 > 0:11:51So we sat for many, many hours in hot rooms,
0:11:51 > 0:11:54tickling locusts on different body parts with a paintbrush...
0:11:54 > 0:11:59Brilliant. Great to see the world's best minds on the case there.
0:11:59 > 0:12:03- Yeah, I wonder what that revealed.- Yeah. Ugh!
0:12:03 > 0:12:05And we found that touch alone
0:12:05 > 0:12:09can cause a locust to switch, very quickly,
0:12:09 > 0:12:11into the swarming form.
0:12:11 > 0:12:15After five weeks, their wings are finally ready,
0:12:15 > 0:12:17so now the locusts can take to the air
0:12:17 > 0:12:21and, for the farmers, this is the start of the real nightmare.
0:12:21 > 0:12:25These airborne swarms have become unstoppable eating machines.
0:12:29 > 0:12:30Finished?
0:12:34 > 0:12:39Yeah. I can't move, let alone sprout wings and fly.
0:12:39 > 0:12:41Meanwhile, back at Sydney University,
0:12:41 > 0:12:45- Professor Simpson has made a remarkable discovery.- Yeah.
0:12:45 > 0:12:48Let me guess, his antics with a paintbrush revealed
0:12:48 > 0:12:52that, in fact, each locust was trying to eat the one in front of it.
0:12:52 > 0:12:54- Correct!- Really?
0:12:55 > 0:12:58They're on a forced march, if you like.
0:12:58 > 0:13:00To avoid being somebody else's lunch,
0:13:00 > 0:13:02they're chasing the lunch in front of them.
0:13:04 > 0:13:06Pretty crazy, huh?
0:13:06 > 0:13:08Australia's 2010 locust plague
0:13:08 > 0:13:10lasted 12 long months.
0:13:10 > 0:13:11And the food bill?
0:13:11 > 0:13:132 billion!
0:13:19 > 0:13:22- Which reminds me, you need to pay me for all those doughnuts.- What?!
0:13:22 > 0:13:26- And you need to work them all off. Come on, get up, give me 10.- Oh, OK.
0:13:26 > 0:13:29Ah! One.
0:13:29 > 0:13:32Ooh! Two.
0:13:32 > 0:13:34- See you next time.- Oooh, three.
0:13:34 > 0:13:36I don't feel very well. Ugh!
0:13:38 > 0:13:40# Wild and weird, wild and weird
0:13:40 > 0:13:43# Really, really wild and really, really weird
0:13:43 > 0:13:45# They're wild and weird Wild and weird
0:13:45 > 0:13:50# They're really, really wild and really, really wild and weird. #
0:13:52 > 0:13:55Wild and weird!