0:00:08 > 0:00:12However well we think we know our planet, the natural world
0:00:12 > 0:00:18still has the power to surprise us, to shock us, sometimes even to
0:00:18 > 0:00:23scare us with its extraordinary events and bizarre behaviour.
0:00:23 > 0:00:28Given modern technology, nature's weirdest phenomena are frequently
0:00:28 > 0:00:33caught on camera wherever and whenever they occur, and this means
0:00:33 > 0:00:37that we can bring you the strangest stories our world has to offer.
0:00:39 > 0:00:45From animals that keel over at the first sign of trouble,
0:00:45 > 0:00:47to bears grabbing a takeaway.
0:00:49 > 0:00:52And a pigeon-snatching predator from the deep.
0:00:54 > 0:00:58With the help of eye-witnesses, experts and scientists,
0:00:58 > 0:01:02we're going to try and explain what on earth is going on.
0:01:23 > 0:01:27The natural world can astound us with intriguing behaviour and
0:01:27 > 0:01:31extraordinary designs, and in these weird events,
0:01:31 > 0:01:35nature seems to have torn up the blueprint altogether
0:01:35 > 0:01:39and come up with something truly bizarre.
0:01:39 > 0:01:43Welcome to the world of nature's weirdest designs.
0:01:43 > 0:01:46We're starting with the animals whose design appears to have
0:01:46 > 0:01:49gone wrong right at the drawing board.
0:01:50 > 0:01:53This is the stuff of myths and legends,
0:01:53 > 0:01:57creatures so strange, they have to be seen to be believed.
0:01:57 > 0:02:03From a lobster that looks half-baked, to a snake in two minds.
0:02:04 > 0:02:09But first, we're off to the USA to meet some animals that may
0:02:09 > 0:02:15look normal, yet something is making them act very strangely indeed.
0:02:17 > 0:02:21Healthy looking goats that appear to drop down dead at the drop of a hat.
0:02:23 > 0:02:25Oh, no, I've killed my wife's goat!
0:02:29 > 0:02:32When the farmer Gene McNutt and his family moved to the peace
0:02:32 > 0:02:37and quiet of Tennessee, they had no idea of the strange events
0:02:37 > 0:02:39that would befall them.
0:02:39 > 0:02:44We moved here to Tennessee in 1988.
0:02:44 > 0:02:48My wife immediately wanted a new goat.
0:02:49 > 0:02:52One of our neighbours was kind enough to bring her home
0:02:52 > 0:02:57a six or eight week old goat and that goat became the pet of the house.
0:02:57 > 0:03:01The McNutts adored their pet goat,
0:03:01 > 0:03:05but then Gene had a very unnerving experience.
0:03:06 > 0:03:13One day, the goat falls down and looks like he's gone stiff with
0:03:13 > 0:03:18rigor mortis and I say, "Oh, no, I killed my wife's goat."
0:03:20 > 0:03:22"What have I done? Has it had a heart attack?"
0:03:22 > 0:03:26I'm standing there just in total amazement,
0:03:26 > 0:03:28trying to figure out what am I going to do.
0:03:28 > 0:03:32Had Gene suddenly developed the power to kill goats
0:03:32 > 0:03:33just by looking at them?
0:03:37 > 0:03:39Well, no.
0:03:39 > 0:03:42Suddenly the goat wriggles a little bit,
0:03:42 > 0:03:45gets up and walks off as if nothing had happened.
0:03:45 > 0:03:49I decided to say nothing to my wife about it
0:03:49 > 0:03:51since the goats appeared to be OK.
0:03:51 > 0:03:55I asked the neighbour about the goat
0:03:55 > 0:03:58because it was something that had never happened before,
0:03:58 > 0:04:02and he says, "Oh," he says, "Those are just old nervous goats."
0:04:02 > 0:04:05He says, "They're from around here."
0:04:05 > 0:04:08Gene's experience wasn't a one-off.
0:04:11 > 0:04:15These goats of the Deep South have a tendency to head south,
0:04:15 > 0:04:18and then rise again unharmed.
0:04:20 > 0:04:23So what's causing the goats of Tennessee to keel over,
0:04:23 > 0:04:26only to be resurrected shortly afterwards?
0:04:29 > 0:04:33Well, there could be a clue in what triggers their downfall.
0:04:34 > 0:04:41Almost any noise that is unusual will cause the goat to stiffen
0:04:41 > 0:04:47or fall over and it'll stay in a fallen position for 30,
0:04:47 > 0:04:5045 seconds and sometimes even up to a couple of minutes.
0:04:50 > 0:04:53Shirley's down.
0:04:53 > 0:04:56Sometimes just a quick movement by a person will cause the goat
0:04:56 > 0:04:58to fall over.
0:04:58 > 0:05:01Almost every morning when I feed the goats,
0:05:01 > 0:05:03at least one of them will fall out
0:05:03 > 0:05:06and all I'm doing is pouring feed out of the bucket.
0:05:08 > 0:05:13So, stress or excitement seems to be a factor in falling over.
0:05:14 > 0:05:16When threatened or surprised,
0:05:16 > 0:05:20many animals have a fight or flight response.
0:05:20 > 0:05:24Their muscles suddenly tense up, as they prepare to run away or attack.
0:05:26 > 0:05:30Freezing for a moment is part of a vital survival strategy
0:05:30 > 0:05:35for some wild animals, but it seems that these goats in Tennessee
0:05:35 > 0:05:38have a glitch in their system.
0:05:38 > 0:05:42Instead of freezing for just a split second, they completely seize up.
0:05:43 > 0:05:47This unusual reaction is unique to a particular breed called
0:05:47 > 0:05:52fainting goats, although they don't actually lose consciousness.
0:05:52 > 0:05:54So what makes this happen?
0:05:56 > 0:06:01Well, it's all down to a genetic disorder called myotonia congenita,
0:06:01 > 0:06:04and it affects how their muscles work.
0:06:04 > 0:06:08The muscle fibres contract as normal, but then they don't relax
0:06:08 > 0:06:12afterwards as they should, so these goats become temporarily paralysed.
0:06:13 > 0:06:16It's a condition that they learn to live with.
0:06:16 > 0:06:21When they're young, a lot of things will make them faint,
0:06:21 > 0:06:23but as they get older, even though they'll stiffen up,
0:06:23 > 0:06:27most of the time they'll find something to lean on
0:06:27 > 0:06:32or they'll get their balance because they know that if they're off balance
0:06:32 > 0:06:34then they'll indeed fall over.
0:06:36 > 0:06:39These domesticated goats don't seem to suffer any ill effects,
0:06:39 > 0:06:42but clearly this could be a problem in the wild.
0:06:44 > 0:06:46Wild goats are renowned for their agility.
0:06:50 > 0:06:54If they fell over whenever they were startled or a predator approached,
0:06:54 > 0:06:57this genetic flaw would prove fatal.
0:07:13 > 0:07:17So why did this weird phenomenon turn up in the goats of Tennessee?
0:07:19 > 0:07:22There's a local legend to explain their genetic quirk.
0:07:25 > 0:07:30About 1885, a man came to a little community called
0:07:30 > 0:07:34Caney Springs here in Marshall County, Tennessee.
0:07:34 > 0:07:37With him he brought three or four little goats.
0:07:37 > 0:07:39The unique thing about these three little goats,
0:07:39 > 0:07:44is that when they're startled, they fall over.
0:07:47 > 0:07:51All fainting goats alive today are descended from that one small
0:07:51 > 0:07:56original flock and it appears that inbreeding has led to some
0:07:56 > 0:07:59genetical mis-wiring and their natural defence system
0:07:59 > 0:08:01has gone awry.
0:08:01 > 0:08:04Now, of course, in the wild, this behaviour would be treacherous.
0:08:04 > 0:08:07It doesn't seem to be too much of a problem in a domestic herd,
0:08:07 > 0:08:11but then having said that, to us, it seems very strange indeed.
0:08:13 > 0:08:16From fainting goats that foxed many farmers,
0:08:16 > 0:08:20we move on to sea creatures which are freaking out fishermen,
0:08:20 > 0:08:24with a design flaw that's clear for all to see.
0:08:27 > 0:08:32We head to the Atlantic Coast of North America, where a fisherman
0:08:32 > 0:08:36landed a lobster that will have you adjusting your TV sets.
0:08:36 > 0:08:40I just jumped aboard the vessel.
0:08:40 > 0:08:45Just caught this blue Maine lobster.
0:08:45 > 0:08:48An astonishing bright blue lobster.
0:08:48 > 0:08:52A vivid contrast to its normally-coloured companion,
0:08:52 > 0:08:56and if one electric blue lobster wasn't shocking enough,
0:08:56 > 0:09:00another turned up, but it didn't stop there.
0:09:01 > 0:09:04Ah, we got ourselves another crazy lobster down here.
0:09:04 > 0:09:06Pretty funky, pretty cool.
0:09:08 > 0:09:13Another was brilliant orange, the colour that lobsters go
0:09:13 > 0:09:16when they're cooked, and yet this one was very much alive.
0:09:17 > 0:09:21And just when they thought they'd seen it all, up from the depths came
0:09:21 > 0:09:28this, an impossible looking lobster with a jaw dropping colour split.
0:09:31 > 0:09:35So, what on earth can explain these colourful crustaceans?
0:09:36 > 0:09:39To find out, we need to delve deeper and take a closer look
0:09:39 > 0:09:42at the colouring of normal-looking lobsters.
0:09:44 > 0:09:48This is what an adult lobster looks like in the wild
0:09:48 > 0:09:52and they get their colour as they grow, from the food that they eat.
0:09:52 > 0:09:56They feed on a diet of crustaceans, shellfish and zooplankton
0:09:56 > 0:09:59and many of these organisms have a red pigment inside them
0:09:59 > 0:10:01called astaxanthin.
0:10:01 > 0:10:05It's the same pigment that makes salmon pink.
0:10:05 > 0:10:08And it even gives flamingos their trademark colour.
0:10:09 > 0:10:14So why don't lobsters turn pink if they're also eating astaxanthin?
0:10:16 > 0:10:18When the red pigment is absorbed into the lobster's body,
0:10:18 > 0:10:22it's laid down in its muscles and into a membrane that
0:10:22 > 0:10:23lies beneath the shell.
0:10:23 > 0:10:27But over a period of time, it migrates into the shell
0:10:27 > 0:10:31where it's transformed by a protein into a blue pigment.
0:10:31 > 0:10:35A little later, it migrates again right up to the
0:10:35 > 0:10:38surface of the shell where it meets another protein which
0:10:38 > 0:10:43transforms it for a second time into a yellow pigment like this.
0:10:43 > 0:10:47Now, when they are all overlaid, we get to see what we see
0:10:47 > 0:10:51when we look at the lobster, this dirty brown-y green colour.
0:10:51 > 0:10:54This layering of colour provides good
0:10:54 > 0:10:58camouflage down on the sea bed where lobsters spend most of their lives.
0:10:59 > 0:11:03It keeps the young safely hidden and allows adults to stalk their prey.
0:11:05 > 0:11:08Understanding the mix of colour layers in normal lobsters
0:11:08 > 0:11:13means we can work out how this design can go wrong.
0:11:13 > 0:11:16What happens if we remove one of those pigment layers,
0:11:16 > 0:11:17say the blue one?
0:11:17 > 0:11:21Well, then we're left with this, an orange-looking lobster.
0:11:22 > 0:11:25But why would a lobster be missing a blue layer?
0:11:27 > 0:11:30Crustacean expert Dr Grant Stentaford
0:11:30 > 0:11:31knows the answer.
0:11:31 > 0:11:34The orange lobsters which are abnormal, are actually missing
0:11:34 > 0:11:37a very important protein, a blue protein which is
0:11:37 > 0:11:40normally in the shell, and that's not produced because of a genetic defect.
0:11:40 > 0:11:46So, it's a genetic design flaw that makes some lobsters bright orange.
0:11:46 > 0:11:49So could the same be true for blue lobsters?
0:11:49 > 0:11:51Well, people may think it's
0:11:51 > 0:11:54because the lobster is missing the red or the yellow pigment
0:11:54 > 0:11:57from the shell, but actually, it's more likely to be due to an
0:11:57 > 0:12:01over-expression of the blue protein, or possibly the fact that the lobster
0:12:01 > 0:12:05is not absorbing those red pigments from the diet that it's eating.
0:12:06 > 0:12:09So the strange looking lobsters of America's East Coast
0:12:09 > 0:12:13are in fact extremely rare colour mutants.
0:12:14 > 0:12:18But what about that extraordinary two-tone lobster?
0:12:18 > 0:12:19What's going on there?
0:12:21 > 0:12:25Just before Halloween in 2012, in the waters
0:12:25 > 0:12:31off of Salem, Massachusetts, this creepy crustacean was hauled in.
0:12:32 > 0:12:35It's mutant orange on one half of its body,
0:12:35 > 0:12:37but normal coloured on the other.
0:12:40 > 0:12:43The men who caught it, Dana and Ryan Duhaime,
0:12:43 > 0:12:45had never seen anything like it before.
0:12:45 > 0:12:48Right away when it came on deck I said, "What is this?"
0:12:48 > 0:12:51I couldn't believe we had a lobster that was orange on one side
0:12:51 > 0:12:54and black on the other and straight, straight, right down the middle.
0:12:54 > 0:12:57We couldn't wait to take it in to show these guys on the dock,
0:12:57 > 0:12:59you know, what do you think of this?
0:13:01 > 0:13:04Unlike us, each side of a lobster's body
0:13:04 > 0:13:06develops completely independently.
0:13:08 > 0:13:11To explain this, we have to go right back to the drawing board.
0:13:11 > 0:13:14Let's look at the beginning of a lobster's life.
0:13:16 > 0:13:19Once the sperm has fertilised the egg,
0:13:19 > 0:13:21it grows and splits into two cells.
0:13:23 > 0:13:28And this is an absolutely critical time for the lobster,
0:13:28 > 0:13:32because this initial spit will define how each side of its body
0:13:32 > 0:13:35develops and remains for the rest of its life.
0:13:35 > 0:13:39Now very occasionally, as it makes this initial split,
0:13:39 > 0:13:43there's a genetic mutation, say in the form of the genes
0:13:43 > 0:13:45that code for colour.
0:13:45 > 0:13:49So, if there's an abnormality on one side, as each of these cells
0:13:49 > 0:13:53is replicated and the lobster grows, then that genetic
0:13:53 > 0:13:56abnormality will be replicated too.
0:13:56 > 0:13:58What we end up with is this,
0:13:58 > 0:14:03a lobster split directly in two with a weird colour mutation on one
0:14:03 > 0:14:08side and it's all down to that initial cell split.
0:14:08 > 0:14:12And that explains what happened with our Halloween lobster.
0:14:12 > 0:14:15But, incredibly, it's not unique.
0:14:15 > 0:14:19This one from Newfoundland has an even stranger design flaw
0:14:19 > 0:14:24which can also be traced back to the original cell split.
0:14:24 > 0:14:26As well as turning black and blue,
0:14:26 > 0:14:29it has a mutation in its sex chromosomes.
0:14:29 > 0:14:35And this means that we end up with a lobster which has female sex
0:14:35 > 0:14:41organs on one half of its body and male sex organs on the other half.
0:14:41 > 0:14:45Almost all of the two-tone lobsters ever recorded have been
0:14:45 > 0:14:47different sexes on each side.
0:14:49 > 0:14:53This rare half-and-half layout is found in other species,
0:14:53 > 0:14:57again where each side of the body develops independently
0:14:57 > 0:15:00and where the males and the female look different.
0:15:03 > 0:15:06We'll see it in butterflies and other insects.
0:15:06 > 0:15:09In those cases, again, the sexes are different on both
0:15:09 > 0:15:12sides of the animal, and we often see wing differences
0:15:12 > 0:15:15so they can be different shapes and even different colours.
0:15:18 > 0:15:21Two-tone lobsters have been surprising fishermen for a
0:15:21 > 0:15:25while now, but scientists have only recently unravelled
0:15:25 > 0:15:28the colourful tales that explain their appearance.
0:15:29 > 0:15:33And with most lobster populations off the Atlantic Coast increasing,
0:15:33 > 0:15:38we'll no doubt see more of these weird and wonderful colour mutants.
0:15:41 > 0:15:45So, colourful crustacean conundrum solved.
0:15:45 > 0:15:48Now to meet a true creature of legend, face to face.
0:15:51 > 0:15:55On September 17, 2013, snake breeder Ross Gregersen
0:15:55 > 0:15:59was checking the Mojave python eggs he was incubating.
0:15:59 > 0:16:03So here's our last clutch of the year, here's the first Mojave.
0:16:04 > 0:16:08- Ross made a shocking discovery. - Here's our second one.
0:16:09 > 0:16:12When I first saw him, I thought he's either dead
0:16:12 > 0:16:15or he's kinked or something cos his neck's pretty goofy looking.
0:16:15 > 0:16:19I poked him and he shifted and I saw this
0:16:19 > 0:16:23and realised that I have a two headed Mojave.
0:16:23 > 0:16:27Amazingly, both heads of this snake are alive.
0:16:30 > 0:16:33And it's not a one-off.
0:16:33 > 0:16:38For snake enthusiasts, two-headed animals are highly prized,
0:16:38 > 0:16:42especially when the split is perfect and symmetrical like this one.
0:16:45 > 0:16:48Ben Siegel owns a reptile shop
0:16:48 > 0:16:52and his striking looking snake has become world famous.
0:16:53 > 0:16:57This is Medusa, she's our two-headed albino Honduran milk snake.
0:16:58 > 0:17:04She was born a couple of years ago and she's the mascot at our store.
0:17:04 > 0:17:09I've been keeping snakes since I was six, so about 34 years,
0:17:09 > 0:17:11and I've never quite seen one like her before.
0:17:11 > 0:17:14We love her, she's really special to us.
0:17:14 > 0:17:18She's perfect other than... she's more than perfect.
0:17:20 > 0:17:24So how do snakes end up with two heads?
0:17:24 > 0:17:27And what kind of double life do they have to lead?
0:17:29 > 0:17:32A snake with two heads is the result of incomplete twinning.
0:17:34 > 0:17:37It happens when the snake embryo is developing,
0:17:37 > 0:17:39either in the egg or the womb.
0:17:40 > 0:17:43The same thing can happen with human embryos
0:17:43 > 0:17:45if they split into identical twins.
0:17:46 > 0:17:51A glitch in the separation process means it grinds to a halt.
0:17:51 > 0:17:56In this case the result is conjoined snake twins each with a head.
0:17:57 > 0:18:01But as this X-ray shows, the head joins a single spine
0:18:01 > 0:18:04and they share the rest of their body.
0:18:04 > 0:18:07Not surprisingly, such an unusual design
0:18:07 > 0:18:10sets the snake several challenges.
0:18:14 > 0:18:17Gordon Burghardt at the University of Tennessee
0:18:17 > 0:18:19has kept and studied two-headed snakes.
0:18:20 > 0:18:22We had one animal,
0:18:22 > 0:18:28that black rat snake that lived for about 20 years and we recorded
0:18:28 > 0:18:30lots of its behaviour,
0:18:30 > 0:18:33but in the wild, they have, I think, great difficulty.
0:18:35 > 0:18:39For a start, how does a two-headed snake decide which way to go?
0:18:42 > 0:18:44Well, let's look at how normal snakes move
0:18:44 > 0:18:48through the world in their natural environment.
0:18:48 > 0:18:51With no limbs, they propel themselves along
0:18:51 > 0:18:53with a slithering motion.
0:18:53 > 0:18:57Snakes can only travel quickly for short bursts,
0:18:57 > 0:19:01but if a predator appears, they need to make a split second decision
0:19:01 > 0:19:03to find cover.
0:19:04 > 0:19:08This is a problem for a two-headed snake
0:19:08 > 0:19:12because each head has an independently thinking brain,
0:19:12 > 0:19:16so it's always in two minds about which way to go.
0:19:18 > 0:19:21But getting around isn't their only problem.
0:19:21 > 0:19:25What happens when they want to eat?
0:19:25 > 0:19:28When we feed her, we take and put her in an empty, clean, open tub,
0:19:28 > 0:19:33and one of our employees actually takes two food items at the same time
0:19:33 > 0:19:36and tries to lure one head to one side and one head to the other side,
0:19:36 > 0:19:39trying to introduce the food at exactly the same time,
0:19:39 > 0:19:40so they both grab it.
0:19:40 > 0:19:44Often at times, we'll actually, when one head swallows it down quickly,
0:19:44 > 0:19:47we'll give it another food item so that ideally you want them to both
0:19:47 > 0:19:48finish at the same time.
0:19:48 > 0:19:50Then after we feed her, we have to take her
0:19:50 > 0:19:52and wash her heads off with water and soap,
0:19:52 > 0:19:56so that she doesn't smell like her food because then both heads
0:19:56 > 0:19:58will try to attack each other just from the smell of the food
0:19:58 > 0:20:00on the head.
0:20:01 > 0:20:07This may sound bizarre, but smell is a critical sense for snakes.
0:20:07 > 0:20:09Although some have good eyesight when it comes to
0:20:09 > 0:20:14finding their prey, most snakes rely on smell more than vision.
0:20:16 > 0:20:19Their tongues play a vital part in smelling.
0:20:21 > 0:20:24They waft odour molecules into a structure called
0:20:24 > 0:20:30the Jacobson's organ, which detects the smell.
0:20:35 > 0:20:37When it comes to the smell of food,
0:20:37 > 0:20:39they follow their tongues to the meal.
0:20:41 > 0:20:44For a two-headed snake, a meal could be confused with
0:20:44 > 0:20:47the smell of leftovers on its other half.
0:20:47 > 0:20:51Evidence surely that two heads aren't always better than one.
0:20:53 > 0:20:57Fortunately, Medusa is well cared for and this helps reduce
0:20:57 > 0:20:59the chance of a mishap.
0:21:00 > 0:21:03But in some cases, this competition for food may be more
0:21:03 > 0:21:06deep-seated than we imagine,
0:21:06 > 0:21:10as Gordon discovered with one of his two-headed snakes.
0:21:10 > 0:21:12From all the records we had heard about,
0:21:12 > 0:21:15the two heads, the animals have necks and they swallow the prey
0:21:15 > 0:21:17and they go to the common stomach.
0:21:17 > 0:21:20So this was what we had thought was going on,
0:21:20 > 0:21:23until we did some x-rays of the animal actually feeding
0:21:23 > 0:21:28and what we found is that the animal actually had two stomachs.
0:21:28 > 0:21:32So their motivational systems were somewhat independent.
0:21:32 > 0:21:35These were individual animals in a sense that they did co-operate
0:21:35 > 0:21:39and learn to do maybe some things a little bit better together,
0:21:39 > 0:21:42but, basically, they were two minds in the same body.
0:21:45 > 0:21:48So, two-headed snakes are rare enough in captivity.
0:21:48 > 0:21:52Just imagine seeing one in the wild.
0:21:52 > 0:21:55Well, believe it or not, that's what happened fairly recently
0:21:55 > 0:21:58when a group of hikers were out in the Yorkshire hills.
0:21:58 > 0:22:01They spotted one of these, an adder, Britain's only venomous
0:22:01 > 0:22:05species of snake, and snapped a few photos before it slithered away.
0:22:05 > 0:22:08It was only when they looked at them more closely afterwards,
0:22:08 > 0:22:13they recognised that the snake actually had two heads.
0:22:13 > 0:22:18An amazing rarity, a UK first and experts think that the animal
0:22:18 > 0:22:21is already a few months, perhaps even a year old,
0:22:21 > 0:22:25so it's doing a good job of surviving in the wild.
0:22:25 > 0:22:28I'm absolutely enthralled by the thought that this snake
0:22:28 > 0:22:31might still be out there somewhere.
0:22:33 > 0:22:35All of these stories make us stop
0:22:35 > 0:22:39and think twice about what happens when nature's blueprints go wrong.
0:22:41 > 0:22:46Whether it's goats overcome by the slightest excitement,
0:22:46 > 0:22:50mutant lobsters equally in touch with their masculine
0:22:50 > 0:22:57and feminine sides, or snakes who are in two minds about life.
0:22:57 > 0:23:00These wonderful, exceptional animals remind us
0:23:00 > 0:23:04that, incredibly, most of the time, nature gets it completely right.
0:23:07 > 0:23:10Next, we meet animals that are pushing the limits of what
0:23:10 > 0:23:17they're designed to do, deploying shocking tactics to secure a meal.
0:23:17 > 0:23:20There's a fish taking a leap into the unknown,
0:23:20 > 0:23:24and a bird using brain power to expand its menu.
0:23:24 > 0:23:28But first, we're heading to the State of Colorado to investigate
0:23:28 > 0:23:30an alarming animal crime wave.
0:23:32 > 0:23:39It's the early hours of July 31st, 2013 and a shifty individual
0:23:39 > 0:23:43is targeting a one-tonne waste bin at the back of this restaurant.
0:23:49 > 0:23:55This isn't so much dumpster diving as dumpster driving.
0:23:58 > 0:24:01The next night, he comes back and steals another dumpster.
0:24:04 > 0:24:06This black bear is a repeat offender.
0:24:09 > 0:24:13On another night in July, a different shady character is caught
0:24:13 > 0:24:17breaking into this chocolate shop in the town of Estes Park.
0:24:21 > 0:24:24This is a high calorie heist.
0:24:29 > 0:24:32So, what's driving these bears to commit a summer crime wave
0:24:32 > 0:24:34in Colorado?
0:24:36 > 0:24:38Well, when it comes to diet,
0:24:38 > 0:24:41black bears eat pretty much what we eat.
0:24:41 > 0:24:44Fruit, vegetables, meat and fish,
0:24:44 > 0:24:47so our food makes a good meal for them too.
0:24:51 > 0:24:55This restaurant robbery took place in Colorado Springs.
0:24:55 > 0:24:57It's nestled at the base of the Rocky Mountains,
0:24:57 > 0:25:01an area with a huge population of black bears.
0:25:03 > 0:25:09But this is the scene of the crime, a full two miles into the city.
0:25:09 > 0:25:15The bear went for the bins around the back, so what lured him
0:25:15 > 0:25:17so far into town?
0:25:18 > 0:25:21Well, he was almost certainly led by his nose.
0:25:22 > 0:25:27Bears have a sense of smell that's even more powerful than bloodhounds.
0:25:27 > 0:25:31Our bear probably smelled the city leftovers from miles away.
0:25:32 > 0:25:35In fact, he might have visited several
0:25:35 > 0:25:38restaurants before being caught on camera at Edelweiss.
0:25:41 > 0:25:45So now we know how the bear targeted the restaurant.
0:25:46 > 0:25:49But how did he manage to move the heavy dumpster?
0:25:51 > 0:25:54Wildlife cameraman Jeff Turner,
0:25:54 > 0:25:57who's filmed bears for decades, has some ideas.
0:25:57 > 0:26:00The bear's able to do what he does with that dumpster
0:26:00 > 0:26:01for three basic reasons.
0:26:01 > 0:26:04The first reason is the way that his feet are built.
0:26:04 > 0:26:08His feet are built much like a human's or a great ape.
0:26:08 > 0:26:12He can actually stand on the flat of his feet which allows him to
0:26:12 > 0:26:15stand up quite comfortably in order to reach the top of the dumpster.
0:26:15 > 0:26:19And then he's got very dexterous paws like his claws
0:26:19 > 0:26:23and individual use of those digits and his paws allow him
0:26:23 > 0:26:25to actually grip things.
0:26:25 > 0:26:28The edge of that dumpster, he can get a good grip on it.
0:26:28 > 0:26:30And then the third element that allows him
0:26:30 > 0:26:33to move it is his strength. They're very, very strong animals,
0:26:33 > 0:26:35very, very powerful, so it's nothing for him
0:26:35 > 0:26:39to move something that heavy once he's in that position.
0:26:40 > 0:26:42Bears have this dexterity and strength
0:26:42 > 0:26:46because of the way they feed in the wild.
0:26:46 > 0:26:49Perhaps, surprisingly, a lot of their calories come from insects,
0:26:49 > 0:26:54which they find by moving boulders and ripping open rotting logs.
0:26:57 > 0:27:02All in all, bears are actually well designed for dumpster-driving.
0:27:02 > 0:27:05But where was the bear going with its haul?
0:27:06 > 0:27:09Well, it turns out it was wheeling it around the corner
0:27:09 > 0:27:13into a car park, to feast on the contents.
0:27:16 > 0:27:19So, why go for a takeaway each night when it could have dined
0:27:19 > 0:27:21al fresco at the back of the restaurant?
0:27:24 > 0:27:27Bears, it seems, prefer to dine alone.
0:27:27 > 0:27:31They don't like to be caught out unawares either by other
0:27:31 > 0:27:33hungry bears or in this case, by humans.
0:27:35 > 0:27:38All the activity and the bright lights at the back
0:27:38 > 0:27:43of the restaurant are enough to put a bear off his food,
0:27:43 > 0:27:47so he takes his meal-on-wheels to a quieter spot in the car park.
0:27:50 > 0:27:54But why is there a spike in bear crimes in late summer,
0:27:54 > 0:27:56when both of these events occur?
0:27:57 > 0:28:00It's all because bears have to hibernate each winter.
0:28:01 > 0:28:05Before they can do this, they must pile on the pounds
0:28:05 > 0:28:09so they have enough fat to live off during the cold months.
0:28:09 > 0:28:13From the end of July onwards, they all start binge eating.
0:28:14 > 0:28:17That's what triggers the late summer crime wave.
0:28:19 > 0:28:24It certainly provides the motive for that raid on the chocolate shop.
0:28:24 > 0:28:26Last week, a young black bear broke into
0:28:26 > 0:28:30Rocky Mountain Chocolate Factory in Estes Park and had a heyday stuffing
0:28:30 > 0:28:34himself silly full of chocolate treats from the popular candy shop.
0:28:35 > 0:28:39Seven times the bear came in, took a pile of chocolate
0:28:39 > 0:28:43and went outside to eat it, getting a massive sugar hit.
0:28:48 > 0:28:50And there's a theory for why the bears in Colorado,
0:28:50 > 0:28:53a landlocked state,
0:28:53 > 0:28:57might be more prone to pilfering than bears living near the ocean.
0:28:57 > 0:29:00In this sort of an environment in the interior of the continent,
0:29:00 > 0:29:03they don't necessarily have access to salmon like they would on the
0:29:03 > 0:29:06coast, so their main source of food at this time of year
0:29:06 > 0:29:08would be berries.
0:29:08 > 0:29:11And berry crops are less nutritious than fish,
0:29:11 > 0:29:14and notoriously unpredictable.
0:29:15 > 0:29:18One year they might be plentiful, the next, they could be thin
0:29:18 > 0:29:23on the ground, driving hungry bears into town to stock up before winter.
0:29:25 > 0:29:29And just one last thing that explains why our bear is
0:29:29 > 0:29:31so confidently calling for a takeout.
0:29:34 > 0:29:37Just look at the way he approaches the dumpster that first night.
0:29:39 > 0:29:44He already knows that this is a giant lunchbox to go.
0:29:44 > 0:29:48And he's clearly enjoyed the contents of these before
0:29:48 > 0:29:54and that's because he probably learned his larceny many years ago.
0:29:55 > 0:29:59Bear cubs learn where to find food from their mothers.
0:29:59 > 0:30:02Research suggests that the cubs of females that forage in urban
0:30:02 > 0:30:05areas grow up to do the same as their mothers.
0:30:07 > 0:30:10And there's increasing evidence that these bears will
0:30:10 > 0:30:14head into town even when there's plenty of natural food on offer.
0:30:15 > 0:30:20The result is a new, streetwise, bear-gang on the block.
0:30:21 > 0:30:24Not only do they have a taste for fast food,
0:30:24 > 0:30:26they've got the brawn, the brains
0:30:26 > 0:30:29and the light-fingeredness to get at it all.
0:30:32 > 0:30:35Our bear's midnight feast came to an abrupt end
0:30:35 > 0:30:38when the owners of the Edelweiss restaurant bear-proofed their
0:30:38 > 0:30:43dumpster and cut off his supply of schnitzel and black forest gateaux.
0:30:43 > 0:30:47But then biologists quite often have to relocate thieving bears
0:30:47 > 0:30:48into the wilderness.
0:30:48 > 0:30:51Trouble is, this doesn't always work.
0:30:51 > 0:30:55You see, these animals have extraordinary navigational ability.
0:30:55 > 0:30:59Even the cubs can build quite complex mental maps far
0:30:59 > 0:31:02better than our own. It's like they've got their own sat-nav.
0:31:02 > 0:31:05So if you take them 60, 70 miles away,
0:31:05 > 0:31:09within a day or two, they can be right back in town.
0:31:10 > 0:31:13But the quest for food takes our next animal
0:31:13 > 0:31:16into even more uncharted territory.
0:31:17 > 0:31:21It's life and death on the waterways of Southern Europe.
0:31:24 > 0:31:28This is Albi, a beautiful town in the South of France.
0:31:29 > 0:31:34It's steeped in history, and famous for the picturesque bridges
0:31:34 > 0:31:36which cross over the River Tarn.
0:31:37 > 0:31:40But these waters hide a shocking secret.
0:31:42 > 0:31:45When pigeons come to drink and bathe on the river bank,
0:31:45 > 0:31:46they are dicing with death.
0:31:48 > 0:31:51A predator is watching their every move.
0:31:53 > 0:31:57And French scientists are capturing astonishing events,
0:31:57 > 0:31:59never seen before.
0:32:12 > 0:32:15Hundreds of miles away in the Spanish city of Zaragoza,
0:32:15 > 0:32:20people are stopping in their tracks to watch the same disturbing scenes.
0:32:20 > 0:32:23THEY SPEAK SPANISH
0:32:26 > 0:32:31One by one, the unsuspecting birds are being plucked from the bank.
0:32:33 > 0:32:37So what is preying on these pigeons and dragging them to a watery grave?
0:32:39 > 0:32:42Huge fish.
0:32:42 > 0:32:46But surely they're risking their own lives to leap onto land?
0:32:46 > 0:32:51So what kind of freakish fish would do something so unnatural?
0:32:51 > 0:32:55Closer inspection reveals a monstrous head with long
0:32:55 > 0:32:57protruding feelers.
0:32:57 > 0:33:01It's a colossal kind of catfish and this species
0:33:01 > 0:33:04isn't meant to be here at all.
0:33:05 > 0:33:09In the 1980s, fishing enthusiasts brought these catfish
0:33:09 > 0:33:14from colder climes, introducing them to several parts of Southern Europe.
0:33:14 > 0:33:19Since then, their numbers have grown steadily, but this is the first
0:33:19 > 0:33:23time they've ever been seen lunging onto land to catch birds.
0:33:25 > 0:33:28To explain why they're making such a splash in the south of France,
0:33:28 > 0:33:32we need to understand how they normally find food, something
0:33:32 > 0:33:37that freshwater fish expert, Jeremy Wade, knows a lot about.
0:33:38 > 0:33:42People tend to think of European catfish as being fairly
0:33:42 > 0:33:45sluggish creatures, snuffling around on the bottom,
0:33:45 > 0:33:49eating things like worms, crustaceans and mussels.
0:33:49 > 0:33:52Normally they live in quite muddy water,
0:33:52 > 0:33:56that's why they've got those feelers stretched out in front of them.
0:33:56 > 0:33:59They have their eyes set towards the top of their head,
0:33:59 > 0:34:02they're very aware of what's going on above them.
0:34:02 > 0:34:05They're very opportunistic so they'll feed on small fish
0:34:05 > 0:34:09but also water birds, things like ducks that are swimming or
0:34:09 > 0:34:13floating on the surface, but I've not heard of them taking pigeons before.
0:34:13 > 0:34:15Catfish are voracious predators.
0:34:15 > 0:34:19To catch their prey, they sneak up behind it.
0:34:20 > 0:34:24At the last moment, the catfish opens its mouth creating a huge
0:34:24 > 0:34:28inrush of water that literally sucks the creature in alive.
0:34:30 > 0:34:33But this won't work with pigeons stood on the bank.
0:34:33 > 0:34:38So how have the catfish managed to modify their technique?
0:34:38 > 0:34:41The catfish are approaching very stealthily.
0:34:41 > 0:34:44They're coming in very close to the water's edge and they appear to
0:34:44 > 0:34:47have their feelers stretched out in front of them and what they're doing
0:34:47 > 0:34:50with those is feeling vibration.
0:34:50 > 0:34:53They seem to be targeting the birds that are moving,
0:34:53 > 0:34:56rather than the ones that are standing still.
0:34:56 > 0:34:58The prey is not going to come to the fish,
0:34:58 > 0:35:01the fish has to go to the prey, which in this case involves
0:35:01 > 0:35:04launching itself on land, making a lunge, a grab.
0:35:05 > 0:35:08These catfish are doing something rarely seen
0:35:08 > 0:35:09anywhere in the world.
0:35:09 > 0:35:13They are propelling themselves into elite company,
0:35:13 > 0:35:16alongside one of nature's most formidable hunters.
0:35:21 > 0:35:25Killer whales off the Patagonian coast also beach themselves
0:35:25 > 0:35:27to catch young sea lions.
0:35:29 > 0:35:34This spectacular behaviour is a risky tactic,
0:35:34 > 0:35:36but at least if they get stuck on the beach,
0:35:36 > 0:35:40these mammals are able to breathe air and the reward
0:35:40 > 0:35:44of a high protein meal is well worth the risk.
0:35:46 > 0:35:50The European catfish are taking the same gamble by hunting pigeons
0:35:50 > 0:35:52but the risks are even greater.
0:35:52 > 0:35:56They can't breathe air and they could end up beached.
0:35:58 > 0:36:02It's the chance of catching the pigeon that makes it all worthwhile.
0:36:04 > 0:36:07But French researchers have found that not all
0:36:07 > 0:36:09the catfish are making the leap onto land.
0:36:11 > 0:36:15It's just a select group of medium sized fish,
0:36:15 > 0:36:17ones which are about a metre long.
0:36:19 > 0:36:23So why do only these fish hunt the pigeons?
0:36:23 > 0:36:26You've got a very gently sloping riverbed there.
0:36:27 > 0:36:31The medium sized fish are able to get within range of the pigeons
0:36:31 > 0:36:33without the pigeons realising they're there.
0:36:33 > 0:36:36A bigger fish tries that, actually half its head is going to be
0:36:36 > 0:36:38out of the water.
0:36:38 > 0:36:40Before it gets close, that pigeon's going to
0:36:40 > 0:36:42realise something's up and get out of the way.
0:36:42 > 0:36:46So these medium sized fish are doing it because they can.
0:36:46 > 0:36:50But hunger may also be driving them to find food on land.
0:36:50 > 0:36:54Maybe the bigger fish are running the river, they are the ones that
0:36:54 > 0:36:57have first choice of the normal foodstuffs, but you have this
0:36:57 > 0:37:00interesting situation where the medium sized fish have access
0:37:00 > 0:37:05to something else that the bigger fish don't seem to be able to reach.
0:37:05 > 0:37:0928% of the lunges result in a meal.
0:37:09 > 0:37:13That's a good hit rate for any predator.
0:37:13 > 0:37:18Fuelled by a high protein diet, these medium sized catfish look set
0:37:18 > 0:37:20to join the big boys pretty quickly.
0:37:21 > 0:37:27And the irony is, as soon as they grow, pigeon will be off the menu.
0:37:28 > 0:37:30But all of this begs the question.
0:37:30 > 0:37:33Given the benefits of this feathered food supply,
0:37:33 > 0:37:37why haven't catfish done this before, in more locations?
0:37:38 > 0:37:40It's to do with where they are.
0:37:40 > 0:37:44An introduced species, these cold blooded killers are now
0:37:44 > 0:37:47living in warmer climes for the first time.
0:37:47 > 0:37:50What I think is probably a factor here is water temperature.
0:37:50 > 0:37:53The water in this part of France is significantly warmer
0:37:53 > 0:37:57than in their historical home range and what this is going to do
0:37:57 > 0:37:58is raise their metabolic rate.
0:37:58 > 0:38:02It's going to make them more active, more predatory in their behaviour,
0:38:02 > 0:38:04they eat more, they grow bigger, faster.
0:38:07 > 0:38:10So, there's a good chance that pigeons will be a la carte
0:38:10 > 0:38:14in more places across Southern Europe as catfish numbers increase.
0:38:16 > 0:38:19To take advantage of their new home, these fish have shown
0:38:19 > 0:38:24remarkable ingenuity, completely changing the way they behave.
0:38:25 > 0:38:26They may look primitive,
0:38:26 > 0:38:31but catfish are really amazingly adaptable animals.
0:38:32 > 0:38:37In the wild, they live for decades and they grow to a colossal size.
0:38:37 > 0:38:39The European record was a fish caught in Italy.
0:38:39 > 0:38:47It measured nearly 3m in length and weighed in at a staggering 144kg.
0:38:47 > 0:38:49It's no wonder that there are stories out there
0:38:49 > 0:38:54about these animals feeding on water birds the size of swans
0:38:54 > 0:38:58and even swallowing dogs that were swimming in fresh water.
0:38:58 > 0:39:02They truly are, if a little unexpectedly, monsters of the deep.
0:39:05 > 0:39:09Big fish have crossed a line in Europe to hunt birds,
0:39:09 > 0:39:15but in our next story in Israel, the tables are dramatically turned.
0:39:20 > 0:39:25Not far from Tel Aviv, in a city park,
0:39:25 > 0:39:29the local hooded crows have been doing something unheard of.
0:39:31 > 0:39:35Like many urban birds, they'll happily take a hand-out,
0:39:35 > 0:39:38but these crows aren't settling for crumbs.
0:39:38 > 0:39:41Local resident Oren Hasson
0:39:41 > 0:39:46enjoys watching their everyday antics in the park.
0:39:46 > 0:39:51Then, one day, Oren filmed a crow taking a piece of bread.
0:39:51 > 0:39:57It dropped it into the water and then...
0:39:57 > 0:40:03Yes, yes, that crow just caught a live fish.
0:40:03 > 0:40:07Crows have never been seen catching fish before and what's really
0:40:07 > 0:40:13extraordinary, is that they appear to be using bait to lure them in.
0:40:15 > 0:40:20So how have these crows learned to fish for a living?
0:40:20 > 0:40:26First, we need to know more about the bird family that they belong to.
0:40:26 > 0:40:28The corvids.
0:40:30 > 0:40:34Many of the corvids have a reputation for their curiosity
0:40:34 > 0:40:38and their problem-solving abilities, and I hope to demonstrate that now
0:40:38 > 0:40:42with this raven, because underneath here I've got a test for him.
0:40:42 > 0:40:43Now go on, jump down.
0:40:43 > 0:40:48Immediately, he's started pulling out the string
0:40:48 > 0:40:52because he knows that on the end of that is a ball
0:40:52 > 0:40:56with some food in it and now he's got the reward.
0:40:56 > 0:40:58Pretty smart, eh?
0:40:59 > 0:41:04And remarkably, there are other cases of corvids in the wild using
0:41:04 > 0:41:07ingenious techniques to find food.
0:41:07 > 0:41:10These rooks have made a pit stop at a motorway service
0:41:10 > 0:41:12station in the UK.
0:41:12 > 0:41:14They've worked out how to get food from the very
0:41:14 > 0:41:19bottom of the litter bins without risking getting inside.
0:41:19 > 0:41:24They use the bin liner as a tool, pulling it up to haul the food out.
0:41:26 > 0:41:30So, birds like crows can be pretty clever.
0:41:32 > 0:41:36But how have the crows in Israel developed their angling abilities?
0:41:38 > 0:41:42Many birds dunk dry bread into water to moisten it before they eat it.
0:41:44 > 0:41:47Perhaps one accidentally ended up with a fish in its mouth.
0:41:49 > 0:41:53That crow might have realised that the fish was a far better meal
0:41:53 > 0:41:55and got hooked on fishing.
0:41:56 > 0:42:00But then several other crows were deliberately seen using
0:42:00 > 0:42:01bread as bait.
0:42:04 > 0:42:07Cambridge Crow expert, Nicky Clayton,
0:42:07 > 0:42:09thinks there's another intriguing possibility.
0:42:09 > 0:42:13Was the bird able to figure out that bread would make a good tool
0:42:13 > 0:42:15to use to lure the fish?
0:42:15 > 0:42:20Did it have a plan, a series of steps in its head that it's worked out
0:42:20 > 0:42:24before it's actually executed any of the behaviours?
0:42:24 > 0:42:29So could these crows be thinking through a clear strategy?
0:42:31 > 0:42:35What's intriguing about the video is whether the hooded crows
0:42:35 > 0:42:39are actually capable of delayed gratification.
0:42:39 > 0:42:43That is do they understand that by using a piece of bread
0:42:43 > 0:42:47as a tool to lure the fish, they can actually get a much better reward
0:42:47 > 0:42:51later, the fish, rather than just eating the piece of bread right now.
0:42:53 > 0:42:57Delayed gratification for an animal like this crow is no mean
0:42:57 > 0:43:01achievement, particularly as it's not something that comes easily
0:43:01 > 0:43:02to humans.
0:43:02 > 0:43:05Child psychologists have known for a long time that
0:43:05 > 0:43:10if you offer children under five one marshmallow now,
0:43:10 > 0:43:15or two marshmallows later and then you leave one on a plate for 15
0:43:15 > 0:43:20minutes, by the end of that period it's almost invariably gone.
0:43:23 > 0:43:25And who can blame them!
0:43:29 > 0:43:32When crows resist temptation like this,
0:43:32 > 0:43:35they also reveal another remarkable ability.
0:43:35 > 0:43:40They've got an awareness of time, and that's something,
0:43:40 > 0:43:43planning ahead, remembering the past that was thought
0:43:43 > 0:43:48until quite recently to be unique to human beings.
0:43:48 > 0:43:54So, crows can make and learn to use tools to help them find food.
0:43:54 > 0:43:58And they're capable of forward planning and delayed gratification.
0:44:00 > 0:44:03So how is all of this possible for a bird brain?
0:44:06 > 0:44:10It turns out that crows are a cut above most of their feathered
0:44:10 > 0:44:12friends when it comes to the old grey matter.
0:44:14 > 0:44:16When we look at the structure of crow brains,
0:44:16 > 0:44:20they have areas which are enlarged compared to other birds
0:44:20 > 0:44:25and these same areas are the ones that in our brains relate to
0:44:25 > 0:44:29memory, planning ahead and delayed gratification.
0:44:31 > 0:44:34These amazing new discoveries are leading scientists to make
0:44:34 > 0:44:38striking comparisons between crows and great apes.
0:44:40 > 0:44:42Relative to their body size,
0:44:42 > 0:44:46crows and chimpanzees have equivalent sized brains.
0:44:46 > 0:44:51They both use tools and scientific tests are starting to show
0:44:51 > 0:44:58that by some criteria, crows are as intelligent as chimpanzees.
0:44:58 > 0:45:02Somehow, these very different animals have both developed similar
0:45:02 > 0:45:04kinds of brainpower.
0:45:09 > 0:45:10It's a mind-blowing thought.
0:45:12 > 0:45:15Who'd have guessed that feeding bread to birds in the park
0:45:15 > 0:45:18could lead to such startling revelations?
0:45:20 > 0:45:23These stories show the extraordinary mental
0:45:23 > 0:45:27and physical lengths that animals will go to get a meal.
0:45:28 > 0:45:33Whether it's a bear pushing the boundaries,
0:45:33 > 0:45:36an astonishing fish out of water,
0:45:36 > 0:45:39or a bird brained genius.
0:45:42 > 0:45:45These animal innovators have stretched the very
0:45:45 > 0:45:48limits of what their brains and bodies are designed to do.
0:45:51 > 0:45:55Next, to the design of some of nature's weirdest defences,
0:45:55 > 0:45:58improbable strategies for personal protection or
0:45:58 > 0:46:01the survival of a whole species.
0:46:03 > 0:46:08From birds acting like lame ducks, to shrinking reptiles.
0:46:10 > 0:46:14But we start in the USA with a defence strategy that appears
0:46:14 > 0:46:16to have backfired terminally.
0:46:19 > 0:46:23From time to time, Americans stumble upon apparently dead bodies.
0:46:26 > 0:46:30- Uncle, pick it up!- I ain't touching that thing.- Must be poisoned.
0:46:30 > 0:46:33- I don't want to touch stuff like that.- Is it going to bite?
0:46:34 > 0:46:37Finding what looks like the corpse of a baby rat can be
0:46:37 > 0:46:39an unsettling experience.
0:46:40 > 0:46:43Watching one lose the will to live in front of your eyes
0:46:43 > 0:46:45is even weirder.
0:46:48 > 0:46:50Has it died of fright?
0:46:53 > 0:46:57Well, no, because these are North American mammals called
0:46:57 > 0:47:00Virginia possums, often known as possums for short.
0:47:02 > 0:47:06See this thing? It looks dead, doesn't he?
0:47:06 > 0:47:09But he isn't. He's just playing possum.
0:47:12 > 0:47:14So what is this possum playing at?
0:47:16 > 0:47:20The American expression "playing possum" refers to someone
0:47:20 > 0:47:25pretending to be dead, and it was inspired by this behaviour.
0:47:25 > 0:47:29This bizarre phenomenon is known as thanatosis.
0:47:29 > 0:47:32The possum goes stiff, then opens its mouth
0:47:32 > 0:47:34and drools with its tongue hanging out.
0:47:35 > 0:47:41Its eyes stay open but its breathing becomes slow and shallow.
0:47:41 > 0:47:45Despite appearances, its heart continues to beat at a normal rate.
0:47:46 > 0:47:52The possum isn't really shutting down, it's just faking it.
0:47:52 > 0:47:55At first glance, this is a fatally flawed defence strategy.
0:47:57 > 0:48:04- The possum is in mortal danger.- Oh, my gosh!- So why doesn't it run away?
0:48:06 > 0:48:10Well, needless to say, possums are not as daft as they look.
0:48:11 > 0:48:15Their natural predators include horned owls, coyotes,
0:48:15 > 0:48:17bobcats, foxes and racoons.
0:48:19 > 0:48:24But with a top speed of about 7mph, running isn't an option,
0:48:24 > 0:48:29so the possum doesn't stand a chance against most of these animals.
0:48:29 > 0:48:32Yet pretending to be dead when confronted with something
0:48:32 > 0:48:36that wants to eat you still seems like a strange response.
0:48:38 > 0:48:42But seeing a coyote hunt a possum suggests how faking death
0:48:42 > 0:48:45might be the best way of avoiding real death.
0:48:49 > 0:48:52The coyote thinks the possum is dead already
0:48:52 > 0:48:54so it doesn't bother to kill it.
0:48:56 > 0:49:00It switches from full-on attack mode to a more gentle,
0:49:00 > 0:49:02meal-handling behaviour.
0:49:03 > 0:49:08But the possum is still on the menu so surely real death is inevitable.
0:49:10 > 0:49:14Predators don't always get stuck into a meal straight away.
0:49:16 > 0:49:21Some species, like owls and foxes, actually hide food for later.
0:49:22 > 0:49:25Anyone keeping chickens will know about this scenario.
0:49:27 > 0:49:30The fox takes one carcass away from the coup
0:49:30 > 0:49:35and hides it in a food cache, returning for another body.
0:49:36 > 0:49:39Substitute a death-feigning possum for a chicken
0:49:39 > 0:49:43and it would find itself being abducted to the cache site
0:49:43 > 0:49:44and then left.
0:49:46 > 0:49:52Left for dead, at which point the possum would make its escape.
0:49:53 > 0:49:57The case of the coyote reveals the second reason that
0:49:57 > 0:49:59playing dead works.
0:49:59 > 0:50:02Predators often kill opportunistically
0:50:02 > 0:50:04and if they aren't actually ravenous,
0:50:04 > 0:50:09they might lose interest in the prey when it appears lifeless.
0:50:09 > 0:50:12That means the possum still has a chance.
0:50:12 > 0:50:16Whilst the coyote's back is turned, it can slip away,
0:50:16 > 0:50:20slightly worse for the experience, but at least it's alive.
0:50:25 > 0:50:30So, faking your own death is a risky but effective strategy.
0:50:32 > 0:50:35But possums aren't the only animals to evolve what might
0:50:35 > 0:50:39seem like counter-intuitive anti-predator strategies.
0:50:43 > 0:50:49It happens here in the UK too. These are little ringed plovers.
0:50:49 > 0:50:51They lay their eggs on a patch of shingle.
0:50:52 > 0:50:57The eggs are speckled for camouflage, but on the ground,
0:50:57 > 0:51:04they're still vulnerable to predators like foxes and jackdaws.
0:51:04 > 0:51:07This jackdaw knows the eggs are there somewhere,
0:51:07 > 0:51:10but the parent birds have left the nest and are flapping
0:51:10 > 0:51:16about right under the jackdaw's nose, but this is all a ruse.
0:51:16 > 0:51:18Look at the bird in the foreground,
0:51:18 > 0:51:22pretending to have a broken wing, trying to look injured
0:51:22 > 0:51:26and vulnerable and show that they would be an easy meal.
0:51:26 > 0:51:29This is a distraction designed to draw the predator
0:51:29 > 0:51:32away from their eggs.
0:51:32 > 0:51:38In this case it didn't work. But the strategy is often successful.
0:51:38 > 0:51:41As soon as the threat has passed, they drop the act
0:51:41 > 0:51:43and return to business as usual.
0:51:46 > 0:51:49Birds are likely to perform these distraction displays
0:51:49 > 0:51:52at the most critical point in their breeding cycle,
0:51:52 > 0:51:55notably when the eggs are just about to hatch.
0:51:55 > 0:52:00If they fail there, then they've wasted an entire breeding season.
0:52:00 > 0:52:03Oh, and one last note on these bizarre displays.
0:52:03 > 0:52:07On land, it's likely that you'll see birds performing them.
0:52:07 > 0:52:11Because they're very agile, they can fly away if there's any trouble.
0:52:11 > 0:52:15Less mobile animals, well, if they practise this sort of deceit
0:52:15 > 0:52:17and get it wrong, it could be fatal.
0:52:19 > 0:52:24Some of nature's best defences involve going unnoticed.
0:52:24 > 0:52:28We're off to Madagascar to discover the ultimate in downsizing.
0:52:30 > 0:52:35A huge island off the coast of Africa, Madagascar is a strange
0:52:35 > 0:52:41looking land, and home to an impressive array of animal oddities.
0:52:43 > 0:52:46Some of the weirdest are the chameleons.
0:52:46 > 0:52:49Here, there are more species of these larger than life
0:52:49 > 0:52:52lizards than anywhere else on earth.
0:52:52 > 0:52:55These eye-catching characters are shaped in the classic
0:52:55 > 0:52:57chameleon design.
0:53:00 > 0:53:05They're big, bold and famous for their telescoping tongues.
0:53:13 > 0:53:17And, of course, for their legendary ability to change colour.
0:53:17 > 0:53:21They use this to communicate with each other
0:53:21 > 0:53:25and to blend into the background to avoid predators.
0:53:29 > 0:53:32But in 2012, scientists were exploring the furthest
0:53:32 > 0:53:37fringes of Madagascar when they discovered this.
0:53:37 > 0:53:42A tiny chameleon, and the world's smallest reptile.
0:53:43 > 0:53:47It was so astonishing that it made headline news.
0:53:51 > 0:53:58It measures just 29mm, and this is a fully grown adult.
0:53:58 > 0:54:02This strange new species, named Brookesia micra,
0:54:02 > 0:54:05is a fraction of the size of its flashy cousins.
0:54:08 > 0:54:13So why would a lizard adopt this extreme miniaturised design?
0:54:15 > 0:54:18Frank Glaw, of the Zoological State Collection in Munich,
0:54:18 > 0:54:23made this diminutive discovery and he was instantly intrigued.
0:54:23 > 0:54:28It's always a great exciting feeling if you discover new species,
0:54:28 > 0:54:31especially if you can immediately recognise it as new.
0:54:31 > 0:54:35In this case, it was so small, it was immediately clear
0:54:35 > 0:54:40that it is different from all the other dwarf Brookesias
0:54:40 > 0:54:45and so it was very exciting to have this small animal in our hands.
0:54:46 > 0:54:50Brookesia micra belongs to a family of highly specialised
0:54:50 > 0:54:52dwarf chameleons.
0:54:54 > 0:54:57These little lizards have found a niche down in the leaf
0:54:57 > 0:54:59litter of Madagascar's forests.
0:55:01 > 0:55:05Scientists think there may be less predators here, and certainly
0:55:05 > 0:55:09their dull brown colouring means they're very well camouflaged.
0:55:11 > 0:55:15There are more of these dwarf chameleon species in Madagascar
0:55:15 > 0:55:17than anywhere else in the world.
0:55:20 > 0:55:24But why is Madagascar such a hot spot for these
0:55:24 > 0:55:27incredibly tiny chameleons?
0:55:27 > 0:55:32What is it about this place that might favour a tiny design?
0:55:32 > 0:55:37Well, it's possible that island life tends to promote the little guy,
0:55:37 > 0:55:39something known as insular dwarfism.
0:55:41 > 0:55:44It suggests that when a normal sized species is
0:55:44 > 0:55:48trapped on an island or on an isolated patch of land,
0:55:48 > 0:55:51over time, it actually evolves into a smaller creature.
0:55:53 > 0:55:57This shrinking process might happen if food was in short supply.
0:55:59 > 0:56:02Only the smaller individuals will survive,
0:56:02 > 0:56:03because they can get by on less.
0:56:05 > 0:56:08When they reproduce, they'll have smaller offspring,
0:56:08 > 0:56:11and so on and so on.
0:56:11 > 0:56:14Down-sizing, then, can be a long term survival plan.
0:56:16 > 0:56:19OK, so that might explain how the other dwarf
0:56:19 > 0:56:23chameleons on Madagascar's mainland came about,
0:56:23 > 0:56:27but Brookesia micra was found on a little island
0:56:27 > 0:56:29off of Madagascar's north coast.
0:56:30 > 0:56:34Here, resources are even more limited.
0:56:34 > 0:56:36We have the large island of Madagascar that favoured
0:56:36 > 0:56:39evolution of tiny Brookesias, and then
0:56:39 > 0:56:44we have tiny offshore islands and so we could expect that natural
0:56:44 > 0:56:49selection will favour even more tiny chameleons than on the mainland.
0:56:49 > 0:56:53So, Brookesia micra's diminutive design may be
0:56:53 > 0:56:55the result of a double dose of down-sizing.
0:56:57 > 0:57:01This remarkable little animal has yet to reveal all of its secrets,
0:57:01 > 0:57:06and, incredibly, scientists think there's a chance that these
0:57:06 > 0:57:08chameleons may get even smaller in the future.
0:57:10 > 0:57:13Shrinking yourself as a defence strategy is certainly pretty weird,
0:57:13 > 0:57:18but then again it's working for the miniature chameleons of Madagascar.
0:57:18 > 0:57:21The question is though, just how much smaller could they get?
0:57:21 > 0:57:26Well, it appears that there might be a limit to miniaturisation
0:57:26 > 0:57:28governed by the complexity of one organ.
0:57:28 > 0:57:32It's not the heart, it's not the lungs, it's not the liver,
0:57:32 > 0:57:34it is in fact, the eye.
0:57:36 > 0:57:39As these stories show us, many of nature's defence plans
0:57:39 > 0:57:42are stranger than we could possibly imagine.
0:57:44 > 0:57:47Whether it's a possum faking its own death,
0:57:47 > 0:57:53birds deploying distraction techniques
0:57:53 > 0:57:58or lizards shrinking into the background,
0:57:58 > 0:58:00they're all strange and curious designs
0:58:00 > 0:58:03showing nature at its weirdest.
0:58:05 > 0:58:06So there you have it.
0:58:06 > 0:58:09We have witnessed some shocking events,
0:58:09 > 0:58:12uncovered some fascinating new science
0:58:12 > 0:58:15and also seen the weird and the wonderful.
0:58:15 > 0:58:18And with its bizarre animal behaviour
0:58:18 > 0:58:20and strange natural phenomena,
0:58:20 > 0:58:23there's no doubt at all that the natural world still has
0:58:23 > 0:58:28the power to leave us both baffled and amazed.
0:58:28 > 0:58:30And with so much more to discover,
0:58:30 > 0:58:34it also leaves us with one last question.
0:58:34 > 0:58:35What on earth next?