Pennod 3 Y Tyrchwyr gyda Iolo Williams

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-Rural Wales offers some of the most

-spectacular sights in Britain.

-But the countryside

-offers much more than just views.

-It's home

-to some our best-loved wildlife.

-But one group of mammals

-is living a secret life.

-By burrowing

-in tunnels miles underground...

-..the way

-these animals live their lives...

-..has been a mystery until now.

-We're going to do something

-that's never been done before.

-By uncovering some of these

-burrowers' tunnels and chambers...

-..we're going to recreate

-an artificial habitat.

-For the first time ever...

-..we'll get an insight

-into their secret lives underground.

-We'll discover what water voles

-do all day in their tunnels...

-..how rabbits cope with nurturing

-dozens of offspring each year...

-..and how small badgers

-learn to cope...

-..with the big world

-beyond the sett.

-Join me, Iolo Williams,

-as we venture...

-..to the magical, hidden,

-subterranean world of the burrowers.

-Spring has sprung...

-..signifying a crucial time

-for the new generation of burrowers.

-It's turned into

-the survival of the fittest.

-Eventually,

-each one of our animals....

-..must turn their backs

-on their burrows...

-..and face the big, wide world.

-In the forthcoming episodes,

-we'll discover...

-..the importance

-of these burrows to the mammals...

-..at this stage in their lives.

-We're back with the rabbits...

-..in this

-remarkable artificial warren.

-Spring is here and

-the rabbits have been very busy...

-..birthing their young.

-Our warren in Devon...

-..is a hive of activity.

-The first litter is the offspring

-of the dominant female...

-..at the beginning of the year.

-Since then, the dominant male

-has been busy mating.

-Each of the does

-now has a nest of baby rabbits.

-Soon they will be fully formed,

-like these confident kits.

-But they still require

-the safety of their warren...

-..with its tunnels and chambers.

-I'm down at the bottom.

-This nest

-has been here longer than the rest.

-I can take a peek inside

-and watch the young kits.

-Judging by the amount of fur they

-have, I'd say they're two weeks old.

-They're dirty creatures,

-to be honest.

-If you could smell the aroma

-in here, you'd know what I mean.

-They regularly

-race through the tunnels.

-The two bucks constantly fight...

-..to establish

-which of them is the dominant one...

-..that will mate

-with all the females.

-They lose their fur when they fight.

-This litter

-was born a couple of weeks ago.

-They're confidently curious...

-..under

-the watchful eye of the mother.

-She knows

-her young are safe underground...

-..and the warren

-soon becomes a nursery.

-To learn more about the warren and

-the rabbits' lives underground...

-..I returned

-to Bicton Park in Devon.

-Earlier in the series...

-..we came across an empty warren.

-It was fumigated

-to reveal each of the entrances.

-Its size was measured underground.

-During winter, workmen

-pumped concrete into the warren...

-..to form a mould.

-A team of volunteers

-has removed the mud...

-..to find out if

-this experiment has been a success.

-Let's find out.

-The warren's structure

-is plain to see.

-Though I've walked over

-numerous warrens in my time...

-..I had no idea

-what existed beneath my feet.

-Wow! Here we are.

-The rabbit warren

-has been uncovered...

-..for the first time ever.

-Look how big it is.

-I didn't expect it to be

-as big as this, I have to admit.

-There are flat pieces on top...

-..which are the entrances.

-You can see the numerous tunnels.

-They form a spider's web...

-..stretching far and wide.

-There are also chambers

-resembling large bulbs...

-..dotted all around.

-The tunnels are interconnected

-with numerous escape routes...

-..in every corner.

-To give you some sort of idea

-how much effort was involved here...

-..the earth the rabbits

-have managed to dig up...

-..is the equivalent of a human...

-..extracting 40 tonnes of earth

-by hand and foot...

-..which is quite remarkable.

-There are other things

-I'd like to show you.

-Here's one of the holes

-leading underground.

-The tunnels are wide enough...

-..to allow two rabbits

-to pass each other underground.

-They have to be wide enough...

-..to accommodate

-two rabbits side by side.

-When animals live underground...

-..other creatures

-either move in with them...

-..or kick them out.

-If you look closely here...

-..you'll notice that tunnel

-is very narrow and short...

-..approximately 1.5m long.

-This isn't

-a rabbit's tunnel but a rat's.

-A family of rats has moved in

-to live alongside the rabbits.

-It's only when you stand back...

-..that you notice

-its scale and complexity.

-That one's a complete warren.

-It's been there for around 20 years.

-I doubt it would get much bigger.

-What's the first stage?

-This the beginning of the process.

-One rabbit

-would've started this warren.

-It would've

-either attracted other rabbits...

-..or have been used

-as a nest to produce offspring.

-It gradually extends

-into new chambers and tunnels.

-The question is, why is this

-located so close to the old warren?

-The reason is that

-the dominant female rabbit...

-..the head

-of the warren over there...

-..has kicked one of the rabbits out.

-It might've grown too large

-or they might've fallen out.

-It's obvious that the rabbit...

-..has started

-building a new warren here.

-If it hadn't been disturbed...

-..perhaps both warrens

-would've eventually linked up.

-Rabbits aren't the only mammals

-to burrow at speed.

-The badgers are busy inspecting

-and using their new burrow.

-Life wasn't always

-this easy for them.

-Each of them has been rescued

-after being found orphaned...

-..in fields and woods.

-Staff at Secret World rescue centre

-have reared them.

-Individually,

-these badgers would not survive.

-As a group,

-they've a better chance of survival.

-One of the badgers arrived

-at the centre later than the rest.

-It's a challenge for her to fit

-into the already-established group.

-She will have to earn her place...

-..and deal with

-the most dominant badger.

-The first thing they do upon

-entering the sett is make a bed...

-..so that they

-can all sleep together.

-If you remember previously...

-..they were very small creatures.

-It's surprising how quickly

-they've grown and developed.

-They're almost four months old now.

-It's nice to see

-the way they've bonded.

-They resemble a close-knit family.

-You'd never think they'd all come

-from different parts of the country.

-They've settled well.

-There are two above me -

-one is lying on top of the other.

-There are a couple beneath me too.

-The chambers are divided.

-There's a sleeping chamber,

-a sewage chamber...

-..and a chamber in which to play.

-It's surprising the way things have

-changed in a short space of time.

-But it's a crucial step...

-..because eventually, they will be

-reintroduced into the wild.

-They must co-operate as a family,

-and at the moment, that's happening.

-Having seen the badgers begin to

-co-operate in our artificial sett...

-..Owen Bidder and I

-headed into the woods...

-..to see

-how badgers co-exist in the wild.

-Are these three female?

-Yes, I think so.

-Yes, I think so.

-

-They're small, aren't they?

-Yes, they are small,

-but the male is larger.

-The females have narrower heads.

-What strikes you when you

-see badgers up close like this...

-..is their prominent

-black and white faces.

-Why do they have that pattern?

-We believe

-it's a way of communicating...

-..how ferocious they can be.

-They're saying, "I can fight,

-so don't try and eat me."

-The head and the mouth

-are very prominent.

-They have sharp teeth

-to defend themselves.

-Something's frightened them.

-I think it's the wind.

-There's a strong wind today

-and they don't like it...

-..because they can't hear

-animals approaching.

-But they like a gentle wind...

-..because it allows them

-to smell the habitat.

-A wind allows them

-to sniff out the territory.

-They commonly use

-a fallen branch of a tree...

-..to start

-burrowing a hole underneath.

-It provides shelter for them.

-Exactly.

-It also helps conceal the burrow.

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-Our young burrowers are growing and

-developing successfully by now...

-..but one pair of mammals

-has been very slow to breed.

-The relationship between the water

-voles was difficult at first...

-..with the pair at loggerheads.

-But the female

-has since formed a nest.

-It's impossible to tell

-how many offspring she's produced.

-When water voles

-are as tiny as this...

-..they're very sensitive

-to any disturbance.

-But we can finally see

-that there are three offspring...

-..which are

-the size of my little finger.

-They are deaf, blind

-and dependent on their mother.

-But soon, their eyes open,

-they gain weight...

-..and are ready to leave the nest.

-They're only a fortnight old...

-..and remarkably, they're already

-half the size of the mother.

-They grow incredibly quickly.

-It's characteristic of water voles.

-Like many small mammals...

-..they must learn

-to develop quickly.

-While they are still suckling,

-they are weaned very quickly...

-..and begin eating solid food,

-as it were.

-This combination

-of rapid development...

-..and constant feeding

-in order to grow...

-..enables them

-to gain necessary weight.

-So many of them perish

-due to malnutrition...

-..and inbreeding

-among the water vole population.

-They must gain substantial weight...

-..in order for them

-to survive in the wild.

-Call it natural selection,

-if you wish.

-Those that thrive will breed

-and ensure the species' continues.

-Water voles

-need to consume enough...

-..to gain an extra one gram

-in weight every single day.

-That's equivalent to

-a woman giving birth to a baby...

-..who'd weigh

-five stone in a few weeks.

-Feeding is crucial. The mother keeps

-a watchful eye on her smallest.

-If he doesn't gain weight...

-..he'll find it hard to survive when

-the time comes to leave the burrow.

-Her family of three

-could become a family of two.

-We've created artificial habitats

-for each of our burrowers.

-But there's another burrower

-that's different from the rest.

-This mammal is reluctant

-to leave the safety of the tunnels.

-It was necessary to create a special

-framework of boxes and tunnels...

-..to film this next burrower -

-the mole.

-Moles live

-a solitary, underground existence...

-..and rarely see daylight,

-making them hard to film.

-Very little footage

-of moles exists..

-..but after a long wait,

-we've captured them on film.

-Idris Jones has been catching moles

-for farmers and gardeners for years.

-He's accustomed to the molehills

-which anger so many gardeners.

-But he's

-never seen moles underground.

-You say this is a feeding run?

-Yes. They live in that hedge.

-They're woodland creatures and

-like living in a safe environment.

-There's no risk of flooding here.

-So they live over there

-and just venture out to feed?

-Yes, just to feed.

-I always thought

-they were field animals...

-..that foraged in the woods,

-but it's the other way around.

-So the feeding run

-is essentially just a tunnel?

-Yes, a network of small tunnels.

-They're three dimensional

-rather than flat.

-Worms and so on

-fall into the runs...

-..and they eat them

-and sometimes store them.

-They bite the heads off -

-their saliva contains anaesthetic...

-..and they bury them in the earth

-and keep them for the winter.

-They're incredible, aren't they?

-They're incredible, aren't they?

-

-Yes, they're clever creatures.

-This mole is a rare example of

-the breed because it's been rescued.

-Moles rarely leave

-their underground tunnels.

-When they do, they're often killed

-by the gardener or farmer.

-This female was caught by a hunter

-who handed her over...

-..for the purpose of the experiment.

-Remarkably, there's

-a similarity between the mole...

-..and a mammal from a completely

-different habitat - the seal.

-They both have smooth bodies...

-..allowing them to move freely

-through the water and the earth.

-Unlike most mammals,

-their legs aren't beneath the body.

-The seal's and mole's front legs

-are at the side of the body.

-In effect, they are both swimming.

-The mole swims through earth

-and the seal through water.

-Two of the young water voles

-are doing well...

-..and are daily gaining weight.

-They are very playful.

-With only a few days to go

-until they leave the burrow...

-..the third sibling

-is very underweight.

-He must learn

-to eat like his parents.

-Lots and lots all the time!

-They are voracious eaters, consuming

-8% of their bodyweight every day.

-They eat

-227 different species of plants.

-There's one food

-they're particularly fond of.

-For most of the year, water voles

-eat grass, reeds and rushes...

-..similar to this vegetation here.

-But it's very coarse to consume...

-..and detrimental to teeth.

-Dyfrig Jones,

-our water vole expert...

-..has been studying these mammals

-for many years.

-This is

-the skull of a water vole, Dyfrig.

-The way it's had to adapt

-to the wild is plain to see.

-Look at its front teeth.

-They're very yellow.

-The enamel is incredibly strong

-and they grow continuously.

-The way the top front teeth work

-in conjunction with the bottom...

-..allows them

-to tear different textures.

-Think about a willow tree.

-They can tear the branches

-with their teeth...

-..to get at the nutrients inside.

-There's an obvious gap between

-the front teeth and the back teeth.

-They call it the diastema gap.

-Yes, it's characteristic

-of the way they chew their food...

-..and the nature

-of the food they eat.

-They use the front teeth to tear and

-the back teeth to grind their food.

-The droppings of the water vole

-are a source of interest.

-They're

-completely and utterly smooth...

-..irrespective

-of what they've eaten and digested.

-They're completely smooth...

-..and that's due to the structure

-of the skull and those back teeth.

-But there's another reason why

-the water voles need strong teeth.

-Unlike any of our other burrowers,

-they burrow with their teeth.

-Their feet are tiny,

-so they burrow with their teeth...

-..and kick the earth

-that has been displaced...

-..out of the tunnel

-with their back feet.

-They're able to dig tunnels

-of up to 70 metres or more...

-..and cut through underground roots,

-occasionally causing trees to fall.

-Soon, the young water voles

-will have to dig their own holes.

-This is true of all the burrowers,

-including the badgers.

-It's inherent in them to burrow.

-The face is long,

-with a thin snout...

-..which gradually thickens as it

-reaches the neck and then the body.

-The legs are short but the paws

-are incredibly powerful.

-Bear in mind

-that these are orphaned badgers.

-Will they know how to burrow without

-the guidance of their parents?

-Sometimes, when badgers

-live in a sett in the wild...

-..parts of the tunnels collapse

-and badgers must dig their way out.

-We've deposited earth in one of the

-tunnels to see what the badgers do.

-They instinctively know

-how to dig their way out.

-Though they have never seen

-another badger do this...

-..they know exactly what to do...

-..and dig their way out right away.

-Years ago, badgers

-were the prey of wolves and bears.

-Since those animals

-have disappeared...

-..the badgers are now

-at the top of the food chain.

-These days, they are

-the most common predator in Wales.

-They eat anything and everything.

-They eat roots, fruit, worms,

-beetles, mice and rabbits.

-They are the most voracious animal

-of all the burrowers.

-But there is one thing

-that the badger cannot escape...

-..and that's TB.

-These are about to embark

-on their final experiment.

-If they pass the test, they

-will be reintroduced into the wild.

-But if they fail,

-they will be culled.

-So we've seen

-our young burrowers...

-..grow, learn and adapt to their

-lives underground and above ground.

-We've seen the way our burrowers

-have adapted perfectly...

-..to their underground lives...

-..and we've also met the mole...

-..with its

-remarkable burrowing skills.

-Next week,

-some of the young animals...

-..are ready

-to venture into the big, wide world.

-And we'll see

-another family of badgers...

-..preparing

-for their release into the wild.

-S4C Subtitles by Adnod Cyf.

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