- 1天前
类别
🐳
动物文字稿
00:14Life on Earth.
00:21Stunning, spectacular, and diverse.
00:30Endless forms, startling and beautiful.
00:34Some animals amaze us with their speed,
00:40their strength,
00:43or their intelligence.
00:52Whilst others fascinate us by, well, being a bit odd.
00:57Creatures that don't normally grab the limelight.
01:01Unconventional and unusual.
01:06Not the big stars, more the character actors.
01:12Let me introduce you to nature's misfits.
01:17I want to show you the extraordinary and rarely seen lives of these evolutionary oddballs.
01:26Their strange habits, their astounding forms, and the hurdles they have to overcome.
01:34It's time nature's misfits got the credit they do.
01:57Before we get going, let's be clear on what makes an animal a misfit.
02:06For some, it's because they appear ill-suited to their habitat.
02:14Others have become so highly specialized in one way that they seem disadvantaged in others.
02:24But first, we'll meet the misfits that stand out because they're different from the rest of their animal family.
02:35So how do these oddities manage to survive?
02:42Could it be that being different can actually give you an edge?
02:56Changqing in China.
02:58In these snowy hills lives a confused creature.
03:12A giant panda.
03:18Pandas are bears.
03:20Close relatives of grizzlies and polar bears.
03:24And of course, bears are ferocious carnivores.
03:31But not the panda.
03:35They've turned their back on their meat-eating past.
03:41And gone veggie.
03:4899% of their diet comes from a single plant.
03:55Bamboo.
03:58Making them a non-meat-eating carnivore.
04:03A true misfit.
04:18In the depths of winter, most bears would be tucked up hibernating.
04:27But not the panda.
04:31The problem is, bamboo contains so little energy that pandas simply can't build up the fat reserves required to hibernate.
04:43Instead, they endure the long freezing winters.
04:49Forcing down bamboo, even when it's frozen stiff.
04:56That's what all the nose twirling is about.
05:02They're breaking up the ice.
05:08A panda must eat up to 18 kilograms of bamboo a day.
05:14Requiring them to feed continuously for 16 hours.
05:21This colossal consumption does have an inevitable consequence.
05:28Pandas have to answer the call of nature 40 times a day.
05:39Giant pandas are so dependent on bamboo that it affects every aspect of their lives.
05:46It even helps explain their relaxed attitude to reproduction.
05:55spring.
05:58Mating season for pandas.
06:06This female is on heat.
06:10Which has aroused the interest of a male.
06:16She's only fertile for a few days and just once a year.
06:23So she needs to get on with things.
06:33That wasn't the response she was hoping for.
06:44She decides to give it another go.
06:51Things aren't going well.
06:54They both know why they're here.
06:56But just can't seem to settle their differences.
07:04Now he gingerly approaches her.
07:15Finally, it happens.
07:20It's little wonder pandas have acquired such a dubious track record for procreation.
07:34Pandas are so reliant on bamboo that if their numbers were to ever dramatically increase,
07:40there might not be enough food to go around.
07:55It all comes back to their veggie and very unbear-like diet.
08:02For our next misfit, it's not their diet that marks them out as different,
08:06but their size that makes them stand out from the rest of their kind.
08:21Vivid colours, incredible eyes, and a lethal weapon of a tongue.
08:41You've got to love chameleons.
08:47But there's one chameleon that is distinctly different.
08:53It's down there, bang in the middle of that big leaf.
09:01Meet the minute leaf chameleon, one of the smallest reptiles on the planet.
09:12Found only on one island off the coast of Madagascar, it's a lizard the size of an ant.
09:21Being this small is tough.
09:27The world's a very dangerous place when you can be mowed down by a millipede.
09:35When it comes to finding a mate, being a miniature misfit can make things rather complicated.
09:42This is a male minute leaf chameleon.
09:48He's constantly keeping an eye out for a partner,
09:51but being so small, he rarely bumps into any others of his kind.
09:59Should he find a potential mate, he has to make the most of it.
10:07A female.
10:17It's an opportunity he can't let slip away.
10:22So he makes his move.
10:27This might not look very fast.
10:32But in chameleon terms, this is a sprint.
10:35A reckless headlong dash.
10:48And it nearly ends in disaster.
10:54It'll take more than that to put him off his stride.
11:07He's back on track.
11:21Finally, he catches up with the larger female.
11:34Gently, he climbs aboard.
11:40He's back on track.
11:41And here he'll stay.
11:59Leaf chameleon lovers have to stick together as they so rarely meet one another.
12:19Being miniature means leaf chameleons can specialize at feeding on all the tiny insects in the leaf litter,
12:26food which is out of reach for other chameleons.
12:31They're not the only misfits that benefit by doing things differently from the rest of their kind.
12:39Purple frogs from India are one of just a handful of frogs that live and feed underground, a bit like
12:45moles.
12:47They only ever pop up to the surface for two weeks a year to find a mate.
12:53So there has to be some frog speed dating.
12:59Flying lemurs have independently evolved wings.
13:05Technically, they're gliding, not flying.
13:10And while they're certainly not lemurs, it's still one hell of a trick.
13:20Flying fish are definitely fish.
13:24They take to the air to avoid underwater predators.
13:31Gliding up to 400 meters.
13:43Sometimes, being a bit different works brilliantly.
13:47Other times, it can be risky.
13:50High in the Bale Mountains of Ethiopia lives an unlikely-looking creature,
13:56which seems to have lost all sense of self-preservation.
14:00This is the only place in the world where you find big-headed mole rats.
14:08They've not got high opinions of themselves.
14:12Just very large heads.
14:17It's the big-headed mole rats lifestyle that qualifies them as a misfit.
14:26There are 36 different species of mole rats.
14:31All specially adapted to live underground.
14:37But the big-headed mole rat is different.
14:44They're the only one of their kind that always feeds above ground.
14:52But round here, that's not necessarily a great plan.
15:00These mountain plateaus are home to Ethiopian wolves.
15:19Unusually for a wolf, they rarely hunt in packs.
15:25They're specialist rat catchers.
15:30And work best as solitary hunters.
15:39Big-headed mole rat senses are designed for their old burrowing lifestyle.
15:48Feeble eyesight.
15:51And poor hearing.
16:06Above ground, they're sitting ducks.
16:26A very close shave.
16:32With the mole rats' determination to forage above the ground,
16:36they could really benefit from having a sentry.
16:40A lookout to check the coast is clear.
16:48And that's exactly what these are.
16:50Moorland chats.
16:52Expert foragers on these high mountain plateaus.
17:00They hang around the mole rats.
17:05Feeding on any bugs and worms dug up in their spoil heaps.
17:24In return for this easy meal,
17:26the chats keep an eye out for troublesome wolves.
17:34Alarm calling if they come too close.
18:00By choosing to feed above ground,
18:02big-headed mole rats have turned their backs on millions of years of life.
18:06This is the most important part of evolution.
18:12For this misfit, being able to get direct access to rich grass
18:17must outweigh the risk of being preyed on.
18:27But sometimes there appears little logic as to why an animal has evolved to be different
18:31from the rest of its animal family.
18:40The primeval forests of New Zealand.
18:45Amongst the undergrowth, something stirs.
18:57A parrot.
18:59But a parrot unlike any other.
19:04This is the world's heaviest and only flightless parrot.
19:16But that's just the start of its misfit credentials.
19:21For this is a kakapo.
19:32Kakapo's can be surprisingly nimble on the ground.
19:42But that's no use to them when their favourite food is up in the trees.
19:52It's not as easy as it perhaps should be.
20:06They awkwardly clamber around.
20:12Relying on their bill as an extra claw.
20:21It's all a bit embarrassing, really.
20:25For a bird.
20:39The kakapo's evolved to be flightless because there were no ground predators on New Zealand.
20:50When the first settlers arrived on these islands, their ships also contained cats, weasels and rats.
20:59When threatened, the kakapo's principal defence mechanism is to stand very, very still.
21:09This strategy has not worked out well for the kakapo.
21:14Now there are only 125 left in the wild.
21:18Which brings us to another major issue.
21:23Kakapo's are one of the world's slowest breeding birds.
21:27And have a delightfully eccentric mating ritual.
21:37Night.
21:39This is when kakapo's minds turned to finding a mate.
21:46A male limbers up.
21:51He plods along a well-worn path.
21:54His personal stomping ground.
21:59In a small hollow that he's carefully excavated, he settles down and calls out for a mate.
22:16The deep, low tone drifts across the valleys.
22:22It can be heard up to three miles away.
22:28He'll do this for up to eight hours, every night, for three months.
22:38As is often the case, it's the females that are the picky ones.
22:43They're only interested in breeding once every five years.
22:49Despite his best efforts, it's not going to happen tonight.
22:54Or any time soon, by the looks of it.
22:56What'sبر.
23:01With no natural predators to keep a check on their population,
23:05kakapo's evolve to be slow breeders.
23:10happily now their numbers are increasing again just very slowly
23:17being the world's most peculiar ill-equipped and unlikely parrot
23:22more than qualifies the kakapo to join the misfit gang
23:28which brings us to our next set of non-conformists animals that all appear
23:35hopelessly ill-suited to the environment in which they live and we're better to
23:40start than a muddy shoreline in Japan
23:53mud skippers look like creatures that began to evolve then got stuck halfway
24:01a fish that can live out of water
24:10although hauling themselves along on their fins doesn't make it look like they've
24:14really cracked it yet survival is tough enough as it is so there must be a good
24:20reason to add that extra level of difficulty well it's all about the mud
24:30it may not look appetizing but mudskippers eat and thrive on mud
24:39it's rich in tiny plants and animals which they filter out
24:58and they've got a neat trick to stay alive in this hostile environment to
25:04breathe on land mudskippers store water in their cheeks surrounding their gills
25:13every now and then topping up the oxygen levels in the water with a big gulp of
25:18air they're not breathing the air directly the air they're gulping in mixes with the
25:28water around their gills allowing them to draw out the oxygen and they're also able to
25:43breathe directly through their skin but being a fish and a tropical fish at that
25:50they're taking a big risk
25:59drying out is their biggest danger only when their skin's wet can they breathe through it
26:12if it dries out they will quickly suffocate to avoid this they're constantly rolling around in the mud
26:26in order to keep their skin moist
26:40mudskippers do seem to be rather disagreeable creatures but perhaps it's a result of having to eat mud every
26:51day
26:51yeah
26:52yeah
26:52yeah
27:02yeah
27:03yeah
27:04yeah
27:22Our next metaphorical fish-out-of-water is also a little ungainly on the land.
27:40Penguins, loved by all.
27:48They are certainly endearing creatures.
27:57Of course, we are used to seeing them in the frozen vastness of Antarctica.
28:02But there is one penguin that has chosen a different path.
28:10Yes, this is a penguin taking a stroll in a forest.
28:16It is a fiordland crested penguin, and this is South Island, New Zealand.
28:23They are here to raise their chicks.
28:29With no natural ground predators, it is a very safe place to nest.
28:37Like any self-respecting penguin, they still love fish, which are, understandably, in short supply in the forest.
28:50Every day, the adults shuffle back and forth to the sea to feed, using crystal clear forest streams as convenient
29:03highways.
29:16The chicks are left to fend for themselves, and like many young birds, they are rather clumsy on land.
29:26It is often early in life that animals seem most ill-suited to their environment,
29:34and face their greatest threats.
29:40A remote, sandy spit in the middle of the Pacific.
29:45Black-footed albatross chicks.
29:49They have been raised on this tiny island, and are now ready to take to the air.
29:56These are mythical birds of the open ocean, completely at one with their environment.
30:04Surely an albatross can't be a misfit.
30:09Once airborne, they are fine.
30:12It is that tricky learning process that puts them in the misfit camp.
30:17These ugly ducklings are cumbersome and awkward on land.
30:22And for a seabird, they are pretty inept in the water, too.
30:34Albatross are such huge birds, they simply can't take off without a strong headwind.
30:41Or a very long run-up.
30:50The chicks practice along the shore.
30:57But eventually their maiden fright will have to be over open water.
31:07This is not the place to linger.
31:19Tiger sharks.
31:25A dozen of them are drawn to the island, purposely to prey on the fledgling chicks.
31:29Let's go.
32:03From the shore, others watch on, waiting for their moment.
32:18One chick builds up courage and sets off.
32:32No sooner is it airborne, the wind drops.
32:35It ditches.
32:38Let's go.
32:42Let's go.
32:44Let's go.
32:53Let's go.
33:12Amazingly, it escapes.
33:21Others also get away.
33:29Once airborne, they'll never look back, leaving their misfit phase behind them.
33:46Beneath the waves, deep down, is a creature that can't escape its misfit ways.
33:52Simply getting around is enough to give them a headache.
34:05A nautilus is the creature that time forgot.
34:09A living fossil.
34:15A primitive inhabitant of the deep sea, which first evolved 400 million years ago.
34:22Distantly related to octopuses and squid, they're the sole survivors of a once abundant group of sea creatures.
34:32Having potted around underwater for near on half a billion years, you might expect them to be perfectly adapted to
34:39life in the ocean.
34:41But of course, we wouldn't be talking about them if that was the case.
34:52Nautili move by forcing water out of a specially adapted tentacle, using the same principle as a jet engine.
35:06But with their jet propulsion thrusting them shell first, their eyes are effectively pointing backwards.
35:20Which makes them rather prone to the odd collision.
35:36With 400 million years of not knowing what hazards you're swimming into, it's amazing they've survived a time.
35:49They can't even avoid the relatives.
35:55Nautili are able to reverse directions.
35:59By bending their tentacle round under their shell, they can gingerly move forward.
36:08Although this doesn't appear to be any improvement.
36:19Nautili may struggle with getting around, but having barely changed for hundreds of millions of years, it can't be doing
36:26them too much harm.
36:28At least their ocean home is pretty constant.
36:34Whereas our next misfit has to deal with some of the most extreme seasonal changes.
36:48The high Arctic.
36:51A bleak and inhospitable place.
36:56This is not where you'd expect to find a caterpillar.
37:04It's the start of summer.
37:07And these Arctic woolly bear caterpillars are in a race against time.
37:15They feast while they can.
37:19Making the most of long summer days.
37:26Their goal is to reach an optimum weight to enable them to pupate into a moth.
37:31Completing their life cycle.
37:37But this far north, summer is brief.
37:44Soon the days begin to shorten.
37:50Winter is coming.
37:53Winter is coming.
37:58Winter is coming.
37:59Winter is coming.
38:00Winter is coming.
38:01Winter is coming.
38:01Winter is coming.
38:05Winter is coming.
38:14Winter is coming.
38:16Winter is coming.
38:17It's under a rock to await its fate.
38:24Still alive, its body starts to freeze.
38:29Its heart stops beating.
38:33Blood turned to ice.
38:43The depths of winter.
38:50For five months, temperatures won't rise above minus 30.
39:10Spring, and the thaw begins.
39:26The caterpillar miraculously rises from the dead, and begins to feed.
39:41But no matter how fast the woolly bears eat, they won't be able to pupate this year either.
39:52The cold closes in once again.
40:00The years pass, the seasons come and go, and still the caterpillars feed while they can, before being wrapped again
40:09in an icy embrace.
40:12By breaking down their cell components, and flooding their bodies with antifreeze chemicals, amazingly, the caterpillars can survive.
40:23Withstanding temperatures as low as minus 70 degrees centigrade.
40:42Eventually, a very special summer arrives, as this will be its last.
40:52only now has it eaten enough to make the transformation into an adult.
40:59It's seven years old.
41:02The world's oldest caterpillar.
41:19Days later, the adult moth emerges.
41:25It must now find a partner and mate.
41:32The woolly bears can only complete their life cycle because of their incredible adaptation.
41:42It's their extraordinary solution to living in such a hostile and marginal habitat.
41:55Many animals have unique adaptations that make them highly specialised.
42:02Marine iguanas are the only lizards on the planet that feed in the sea.
42:08Grabbing mouthfuls of seaweed whilst holding their breath.
42:16With a sticky 60 centimetre tongue and some of the largest claws of any mammal.
42:23Giant anteaters can devour 30,000 termites in a day.
42:31Their bodies are so highly specialised, they can now only ever feed on these tiny insects.
42:40Which isn't a bad thing.
42:41By weight, termites are more protein rich than any other food source.
42:49Texas blind salamanders spend their entire lives in the pitch black of caves.
42:56With zero light, eyes would be utterly useless.
42:59A drain on precious energy.
43:02Now they sense their prey with receptor cells dotted along their bodies.
43:10But being such a specialist animal can also have its downsides.
43:14To be honest.
43:23Vanuatu, in the South Pacific.
43:26On a pristine tropical island like this, you might expect to find all manner of exotic-looking crabs.
43:44But here, there's a real oddity.
43:56This mighty beast is a coconut crab.
44:05With a metre-wide leg span, weighing up to four kilograms, this is the world's largest land invertebrate.
44:20The crabs have evolved to be giants, to feast on a tropical delicacy.
44:28The clue's in the name.
44:30But just to be clear, coconut crabs do actually eat coconuts.
44:38They're one of the few animals strong enough to break the tough husk.
44:47The whole process can take several hours.
44:53But the reward is well worth it.
45:03Coconut crabs' outlandish size and strength might be an advantage when it comes to feeding.
45:15But it can be fatal when it comes to reproducing.
45:20Like all crabs, these giants have to release their eggs in the sea.
45:28But unlike most crabs, they can't breathe underwater.
45:36And because they've grown so heavy, if they're ever washed out of their depth, they'll never recover.
45:41Eventually, drowning.
45:49A female.
45:51Her belly bulging with eggs.
46:00Carefully, she edges towards the pounding waves.
46:04One missed step could mean disaster.
46:08A female.
46:09A female.
46:20A female.
46:20A female.
46:21A female.
46:23A female.
46:29A female.
46:31A female.
46:32A female.
46:33A female.
46:33A female.
46:34A female.
46:35A female.
46:36A female.
46:36A female.
46:36A female.
46:37A female.
46:38safe. Coconut crabs incongruous size has evolved so they can feed on coconuts, but they're
46:49not the only misfits whose very special diet has resulted in a very specialised body.
47:05Madagascar, in dead of night, a ghoulish creature awakes. Half bat, half monkey,
47:24and with a grotesquely elongated finger.
47:30The eye-eye is undoubtedly very peculiar, like a cross between ET and Nosferatu. In fact,
47:38it's a type of lemur, a primate, a misfit in our own animal family.
47:55Their curious features allow them to find their favourite food. That extraordinary finger taps
48:04at the branch up to ten times a second. Ears pick up on the unmistakable echo of a hollow.
48:17Teeth gnaw a hole. They're the only primates whose teeth grow constantly throughout their
48:27lives, just like rodents. Finally, she hooks the prize. An insect grub.
48:44Eye-eyes feed almost exclusively on these grubs, fishing them out from rotten wood.
48:55Normally, birds like woodpeckers would feed like this, using their bills to break through the wood.
49:02But woodpeckers never reached the eye-eyes island home of Madagascar.
49:09Instead, these primitive primates have evolved to fill the woodpecker's niche, exploiting a resource
49:16that no other animal can get to.
49:22On first impressions, other misfits' strange bodies are much harder to explain.
49:40On the forest floor in Malaysia, an alien creature emerges.
49:52It's an insect, a type of fly, and this is a male.
50:07If you think he looks unearthly now, just wait to see what happens next.
50:26He starts by gulping in air, forming clear bubbles in his head.
50:36He forces these bubbles into the stalks supporting his eyes.
50:49Like blowing up a balloon, the stalks stretch, getting longer and longer.
51:10A few final adjustments, and a couple of hours in the sun to let its skin go hard, and the
51:17look is complete.
51:22Meet the stalk-eyed fly.
51:28These bizarre stalks don't help the fly see any better.
51:35In fact, quite the opposite.
51:36It's thought they reduce the effectiveness of their eyesight.
51:40So there must be another benefit that's allowed these implausible appendages to evolve.
51:53In the evening, a group of males gather.
51:58They size each other up.
52:01Eyeball to eyeball.
52:03Eyeball to eyeball.
52:09There's some aggressive posturing.
52:15But a full-on fight never breaks out.
52:21The stalks are sort of measuring sticks, a way to gauge how strong a rival is.
52:33As they square up, the male with the widest stalks wins.
52:48Males with broad stalks are also considered the more desirable by the females,
52:53and will therefore produce the most offspring.
52:58It's sexual selection, rather than natural selection,
53:02that has allowed the stalk-eyed fly's unique appearance to evolve.
53:09Our final misfit has to be one of the most peculiar, yet most endearing animals on the planet.
53:24It's not often you see a sloth in a rush.
53:30This is a three-toed sloth.
53:33A female.
53:37And she's ravenously hungry.
53:41It's the leaves that she's after.
53:47However, in order to protect themselves, rainforest leaves are often tough, rubbery and full of toxins.
53:55They're indigestible and lacking in energy.
54:01But that hasn't stopped the sloth.
54:05With large, multi-chambered stomachs containing a unique mix of bacteria, they're able to deal with the tough leaves.
54:16But it's not a quick process.
54:22Sloths have the slowest digestion of any mammal.
54:27It can take them two weeks to process a single meal.
54:33And it's a hopelessly inefficient process.
54:39Sloths had two options.
54:46Either they had to eat more or do less.
54:55Sloths evolved to do less.
55:02Their entire lifestyle is all about expending as little energy as possible.
55:09The word sloth has come to mean laziness.
55:13But sloths aren't lazy.
55:14They've just developed a laid-back survival technique.
55:21They've just developed a little bit.
55:22Although watching them does make you feel like a nap.
55:31But their legendary, lethargic manner does have a downside.
55:42Harpy eagles.
55:48And jaguars.
55:53Both regularly hunt sloths.
56:01Without speed as a defense, sloths had to go down another route.
56:08Camouflage.
56:12They've become the world's only vaguely green mammal.
56:19Of course, there are plenty of green bugs.
56:24Green lizards.
56:26And green birds.
56:31But can you name another green mammal?
56:36There aren't any.
56:39So how have they done it?
56:41Their thick, coarse fur has evolved to house entire communities of algae.
56:48Single-celled plants.
56:53It's the algae that's turned them green.
56:56The perfect way to blend into the forest.
57:02Sloths may come across as comical and incongruous.
57:06But they're actually highly evolved.
57:09And extremely well adapted at their chosen way of life.
57:17In fact, all misfits prove that being different does give you an edge.
57:22It can make you very successful.
57:26The result is a group of wonderfully eccentric creatures.
57:32Creatures we should be grateful we share our planet with.
57:42Yet now, largely due to our influence, over half of the animals in this program are endangered.
57:55It's because these animals are so specialised, they're often more prone to the threats that face all wildlife.
58:01That's why we should be looking out for them more than ever before.
58:06They deserve our admiration, these misfits, these quirks of nature, turning their oddness into opportunity.
58:15They might be a bit weird, but they're equal to any of the wonders of the planet, in the glorious
58:20spectacle that is life on Earth.
58:31Tonight on BBC Two, take a walk by the River Lea.
58:34And along the way, discover London's industrial past at eight.
58:38And later, the multi-Oscar-winning musical La La Land gets its network premiere at nine.
58:45But on the way next this morning, more homes under the hammer.
58:57We'll see you next time.
评论