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0:00:01 > 0:00:05- Rural Wales offers some of the most - spectacular sights in Britain.
0:00:08 > 0:00:12- But the countryside - offers much more than just views.
0:00:12 > 0:00:15- It's home - to some our best-loved wildlife.
0:00:16 > 0:00:20- But one group of mammals - is living a secret life.
0:00:22 > 0:00:25- By burrowing - in tunnels miles underground...
0:00:26 > 0:00:30- ..the way - these animals live their lives...
0:00:30 > 0:00:35- ..has been a mystery until now.
0:00:35 > 0:00:39- We're going to do something - that's never been done before.
0:00:39 > 0:00:44- By uncovering some of these - burrowers' tunnels and chambers...
0:00:44 > 0:00:48- ..we're going to recreate - an artificial habitat.
0:00:48 > 0:00:51- For the first time ever...
0:00:51 > 0:00:55- ..we'll get an insight - into their secret lives underground.
0:00:55 > 0:01:01- We'll discover what water voles - do all day in their tunnels...
0:01:02 > 0:01:07- ..how rabbits cope with nurturing - dozens of offspring each year...
0:01:07 > 0:01:10- ..and how small badgers - learn to cope...
0:01:11 > 0:01:13- ..with the big world - beyond the sett.
0:01:13 > 0:01:17- Join me, Iolo Williams, - as we venture...
0:01:17 > 0:01:21- ..to the magical, hidden, - subterranean world of the burrowers.
0:01:22 > 0:01:24- Subtitles
0:01:29 > 0:01:31- Subtitles
0:01:36 > 0:01:38- Subtitles
0:01:45 > 0:01:50- Last week, we saw how the burrowers - born at the end of the winter...
0:01:51 > 0:01:53- ..were growing and developing.
0:01:59 > 0:02:02- Many rabbits were ready to leave.
0:02:02 > 0:02:06- There were concerns - about one young water vole...
0:02:06 > 0:02:08- ..that wasn't developing well.
0:02:09 > 0:02:12- The young badgers are busy bonding.
0:02:13 > 0:02:17- They've reached an age when - they need to be tested for TB.
0:02:18 > 0:02:21- They've now visited the vet.
0:02:21 > 0:02:24- These experiments and results...
0:02:25 > 0:02:30- ..are crucial to the future of the - individuals and the group itself.
0:02:30 > 0:02:34- We'll discover the results later.
0:02:45 > 0:02:49- Last week, we introduced - another burrower to the series.
0:02:49 > 0:02:52- The mole.
0:02:52 > 0:02:57- We saw how well it adapted - to life underground.
0:02:58 > 0:03:00- Moles, who live - a lonely life underground...
0:03:01 > 0:03:03- ..seldom venture above ground.
0:03:04 > 0:03:07- The tunnels provide - for all their needs.
0:03:07 > 0:03:11- This is important since the mole - must eat every four hours.
0:03:12 > 0:03:17- The mole has a special way to store - food in case it becomes scarce.
0:03:17 > 0:03:20- Moles waste nothing.
0:03:20 > 0:03:25- If a mole can't eat a whole worm, - it bites off the head...
0:03:25 > 0:03:29- ..and paralyzes the worm - with its poisonous saliva.
0:03:29 > 0:03:33- With the worm seemingly lifeless - but still alive...
0:03:33 > 0:03:38- ..the mole takes it to a pantry of - live creatures in a special chamber.
0:03:38 > 0:03:42- The mole can then eat - whenever it wants.
0:03:42 > 0:03:47- These food chambers sometimes - contain thousands of worms.
0:03:53 > 0:03:57- Following on from the success of the - concrete in the rabbit's warren...
0:03:57 > 0:04:00- ..we did the same - to the mole's tunnels.
0:04:00 > 0:04:01- Here's the result.
0:04:01 > 0:04:06- Mole tunnels - have been unearthed here.
0:04:06 > 0:04:11- They stretch all the way from there - to my leg here...
0:04:11 > 0:04:16- ..and almost in a half-circle - around and back.
0:04:16 > 0:04:20- Here and there, - you can see flat areas such as this.
0:04:21 > 0:04:23- That's the mole's tunnel.
0:04:23 > 0:04:29- It stretches for 28.3 metres - in length.
0:04:29 > 0:04:31- That's incredible.
0:04:31 > 0:04:34- A small animal, - the size of my hand...
0:04:34 > 0:04:37- ..that's the sum total of a mole.
0:04:37 > 0:04:41- But, in contrast - to the other burrowers...
0:04:41 > 0:04:45- ..the mole lives - its entire life underground.
0:04:45 > 0:04:52- It survives on worms - that fall into the tunnels.
0:04:52 > 0:04:58- That's why these tunnels - need to be so long for the mole.
0:05:02 > 0:05:06- The mole is king - for hunting underground.
0:05:06 > 0:05:09- Its best tool is its sensitive nose.
0:05:10 > 0:05:12- It has over 5,000 smelling cells...
0:05:12 > 0:05:16- ..and thousands of nerves - transmitting messages.
0:05:16 > 0:05:21- It also uses its nose - to feel its way around the tunnels.
0:05:21 > 0:05:25- This is important because - a mole's eyes is very small.
0:05:25 > 0:05:28- In the darkness, - it is virtually blind.
0:05:28 > 0:05:31- It is also sensitive - to small movements...
0:05:32 > 0:05:35- ..and can sense immediately - when a worm falls into the tunnel.
0:05:35 > 0:05:40- It searches for the head before - pulling the worm through its paws...
0:05:40 > 0:05:44- ..to clean the meal - before eating it.
0:05:53 > 0:05:57- We've been keeping an eye - on the badgers...
0:05:57 > 0:06:01- ..to see if they communicate - by smell.
0:06:05 > 0:06:08- Badgers can choose - how to mark their territory...
0:06:09 > 0:06:12- ..either by using - their waste material...
0:06:12 > 0:06:16- ..or by marking a tree - using glands under the tail.
0:06:16 > 0:06:20- You need a good nose - to smell the different aromas.
0:06:20 > 0:06:24- They rely far more - on their noses than their eyes.
0:06:24 > 0:06:28- They smell everything carefully - and breathe deeply...
0:06:28 > 0:06:31- ..to evaluate - all the aromas quickly.
0:06:32 > 0:06:35- This is something - I've never seen before.
0:06:35 > 0:06:37- One is rubbing up against the other.
0:06:38 > 0:06:40- What's happening there?
0:06:40 > 0:06:44- This is an important part - of keeping the family together.
0:06:45 > 0:06:49- They rely strongly - on their noses and aromas.
0:06:49 > 0:06:53- They mark each other - with a liquid...
0:06:53 > 0:06:57- ...secreted from a gland - under the tail.
0:06:57 > 0:07:02- As if to say, "You're part - of this family, you can stay."
0:07:02 > 0:07:07- If it's a dark night - and they can't see the creature...
0:07:08 > 0:07:14- ..they can smell it easily - to determine whether it's friendly.
0:07:14 > 0:07:19- Our badgers won't mature sexually - until next spring.
0:07:19 > 0:07:24- That's when their position within - the group becomes all-important.
0:07:33 > 0:07:37- What can you tell us about - the creature from that skull?
0:07:38 > 0:07:42- The main thing - is the strength of the animal.
0:07:43 > 0:07:49- We can see a very strong crest - on this skull.
0:07:49 > 0:07:57- The main biting muscles - have a strong foundation.
0:07:57 > 0:08:00- This joint at the back of the jaw...
0:08:00 > 0:08:03- ..is very strong in badgers.
0:08:03 > 0:08:05- It's the only species...
0:08:05 > 0:08:10- ..where you cannot dislocate the jaw - from the rest of the skull.
0:08:10 > 0:08:14- As a result, - the bite is extremely strong.
0:08:15 > 0:08:17- The skull is strong...
0:08:17 > 0:08:21- ..and the general strength - of the badger is well-known.
0:08:21 > 0:08:27- It can burrow up to 300 metres - of earth underground.
0:08:27 > 0:08:31- When you think of that amount - of earth, it's incredible.
0:08:31 > 0:08:35- The other striking features - are the small bones in the nose.
0:08:37 > 0:08:41- These greatly overlap each other.
0:08:42 > 0:08:47- As a result, if you laid them - all flat, the surface area is huge.
0:08:47 > 0:08:52- That's how the badger - has such a strong sense of smell.
0:08:53 > 0:08:57- Its sense of smell is 800 times - stronger than that of a human.
0:08:57 > 0:09:04- If a badger eats a little of - everything - mice, berries, etc...
0:09:04 > 0:09:08- ..why does it require - such a strong skull and muscles?
0:09:09 > 0:09:13- When you look at the life - of a badger...
0:09:13 > 0:09:16- ..they are very social animals...
0:09:17 > 0:09:22- ..they hunt for their families - but they're also very territorial.
0:09:22 > 0:09:24- They defend their territory.
0:09:25 > 0:09:28- The males are often involved - in fierce fights...
0:09:29 > 0:09:31- ..to the point of death sometimes.
0:09:32 > 0:09:37- Like many other animals, - they try to avoid each other...
0:09:37 > 0:09:41- ..but if two are in close proximity, - there will be a skirmish.
0:09:42 > 0:09:44- The injuries can be serious.
0:09:53 > 0:09:57- The rabbits are growing quickly.
0:09:57 > 0:10:00- A few weeks ago, - they were blind and fragile.
0:10:00 > 0:10:04- By now, they are very similar - to their parents.
0:10:04 > 0:10:08- The little rabbits - must also learn quickly.
0:10:08 > 0:10:13- Out in the wide world, - almost everything eats rabbits.
0:10:15 > 0:10:17- The rabbits are now a month old.
0:10:17 > 0:10:21- They've taken every important step - in their development.
0:10:21 > 0:10:24- The time has come - to follow the mother...
0:10:24 > 0:10:27- ..and leave the warren - for the first time.
0:10:27 > 0:10:31- Imagine living in the darkness - of the warren for weeks...
0:10:32 > 0:10:35- ..before venturing out to - the wide world for the first time.
0:10:37 > 0:10:40- But it's also the time - when foxes wait by the holes...
0:10:40 > 0:10:44- ..to exploit the shock and - confusion of the little rabbits...
0:10:45 > 0:10:49- ..as they venture out for - the first, and possibly last, time.
0:10:49 > 0:10:52- Small rabbits know little - about life beyond the warren.
0:10:53 > 0:10:54- They are very nervous.
0:10:54 > 0:10:58- Ceri and I find a vantage point - and wait for them.
0:10:58 > 0:11:03- We've built a cage around the - warren to safeguard the rabbits.
0:11:03 > 0:11:06- For them, - it's a terrifying experience.
0:11:08 > 0:11:13- They smell the fresh air a few times - and out they come.
0:11:13 > 0:11:17- The first steps - into the great outdoors.
0:11:17 > 0:11:19- They see light for the first time.
0:11:20 > 0:11:24- There's new light, - new smells, new sounds.
0:11:24 > 0:11:28- Everything is new to them. - They taste food for the first time.
0:11:29 > 0:11:31- They've only drunk milk.
0:11:32 > 0:11:37- It's surprising to see these - small rabbits cleaning each other.
0:11:37 > 0:11:40- They're tame, they're not related...
0:11:40 > 0:11:43- ..but they're looking out - for each other.
0:11:43 > 0:11:49- It's important for the group - to strengthen the bond between them.
0:11:51 > 0:11:54- It's an important part - of life as a group.
0:11:54 > 0:11:59- When one eats, - another will look out for danger.
0:11:59 > 0:12:04- Everything eats them - buzzards, - tawny owls, stoats, weasels...
0:12:04 > 0:12:06- ..foxes and badgers
0:12:06 > 0:12:11- They're a very important part - of the food chain.
0:12:11 > 0:12:13- A lot of other creatures - rely on them.
0:12:14 > 0:12:18- They must keep an eye out - for everything.
0:12:19 > 0:12:23- The rabbit warren - has been designed carefully...
0:12:23 > 0:12:26- ..with a variety - of tunnels and chambers...
0:12:27 > 0:12:30- ..to allow the rabbits - to escape quickly...
0:12:30 > 0:12:35- ..from stoats or any other creature - that preys on them.
0:12:36 > 0:12:39- That was evident - in the Bicton warren.
0:12:44 > 0:12:50- This is a very interesting feature, - right in the middle of the warren.
0:12:50 > 0:12:56- There's a junction, with tunnels - heading in different directions.
0:12:56 > 0:13:02- If a stoat follows a rabbit - along this tunnel...
0:13:02 > 0:13:05- ..the rabbit can cut across, - cut back...
0:13:05 > 0:13:07- ..and go back out.
0:13:07 > 0:13:10- The stoat ends up confused - in the tunnels.
0:13:10 > 0:13:14- It's incredible. This is - the first time I've seen this.
0:13:14 > 0:13:16- It's a real eye-opener.
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0:13:24 > 0:13:24- Subtitles
0:13:24 > 0:13:26- Subtitles- - Subtitles
0:13:35 > 0:13:36- In Somerset...
0:13:37 > 0:13:41- ..our badgers still live in - the burrow that was built for them.
0:13:41 > 0:13:45- The intention is to release them - into the wild.
0:13:45 > 0:13:50- That's about to happen to a group - of badgers in the RSPCA centre.
0:13:54 > 0:13:56- We're here in Somerset.
0:13:57 > 0:13:59- The sun is shining down on us.
0:13:59 > 0:14:05- We're here to see the badgers - the RSPCA is preparing to release.
0:14:05 > 0:14:09- They're hoping to return them - to the wild.
0:14:09 > 0:14:12- I have some collars in this box.
0:14:12 > 0:14:15- These devices will help us - track the badgers.
0:14:16 > 0:14:20- We can track their whereabouts - for the next six months.
0:14:33 > 0:14:37- The badger has been sedated...
0:14:37 > 0:14:39- ..using anaesthesia.
0:14:40 > 0:14:43- This will allow it - to be marked with a tattoo.
0:14:44 > 0:14:49- If the badger - is discovered again in the future...
0:14:50 > 0:14:54- ..we can make a note - of where it came from.
0:15:09 > 0:15:15- We're also checking to see - if the signal works...
0:15:15 > 0:15:19- ..and if the frequency - on the radio if OK.
0:15:21 > 0:15:24- When we follow the badger - in its habitat...
0:15:25 > 0:15:28- ..in the area it will be - released back into the wild...
0:15:29 > 0:15:32- ..we can make sure - we're tracking the correct badger.
0:15:33 > 0:15:38- We're securing the collar - and radio around the badger's neck.
0:15:42 > 0:15:47- The badger will be returned - to the pen...
0:15:48 > 0:15:52- ..to regain consciousness.
0:15:52 > 0:15:56- When it's alert, it will be - returned to the bottom pen.
0:16:00 > 0:16:03- They don't feel any pain, - they're under anaesthesia.
0:16:04 > 0:16:07- They're not harmed in any way.
0:16:25 > 0:16:28- Life can be difficult for rabbits.
0:16:28 > 0:16:32- They're preyed upon by birds - and other animals...
0:16:33 > 0:16:35- ..but they can defend themselves.
0:16:35 > 0:16:38- Look at their ears.
0:16:38 > 0:16:42- They're large ears - - they have strong hearing.
0:16:42 > 0:16:48- The ears can turn - facing forwards, - to the side and backwards.
0:16:48 > 0:16:53- They have strong eyesight. The eyes - are located at the side of the head.
0:16:54 > 0:16:58- They can see from the back, - all the way around to the front.
0:16:58 > 0:17:04- That makes it almost impossible for - anything to creep up on a rabbit.
0:17:05 > 0:17:07- The nostrils - are moving all the time.
0:17:07 > 0:17:09- They have a strong sense of smell.
0:17:09 > 0:17:12- If a prey does get anywhere near...
0:17:12 > 0:17:15- ..rabbits can run very quickly.
0:17:15 > 0:17:18- They can also burrow underground.
0:17:18 > 0:17:23- Down there, - they're safe from almost anything.
0:17:25 > 0:17:30- Rabbits have the ability to breed...
0:17:30 > 0:17:33- ..and increase - their numbers quickly.
0:17:33 > 0:17:37- That's very important - because they are preyed upon.
0:17:37 > 0:17:40- They need to breed quickly.
0:17:40 > 0:17:44- Do many rabbits survive - the first few months...
0:17:44 > 0:17:46- ..or do they die quickly?
0:17:46 > 0:17:50- About 90% die within the first year.
0:17:50 > 0:17:53- That's why they need - to breed quickly.
0:17:53 > 0:18:00- This has given me my first - opportunity to see rabbits close-up.
0:18:01 > 0:18:04- The younger ones are very pretty.
0:18:05 > 0:18:08- Yes, we have some - very young rabbits here.
0:18:08 > 0:18:12- Some have only just emerged - from the warren.
0:18:12 > 0:18:15- The larger rabbits are really large.
0:18:15 > 0:18:18- Are they as large as that - in the wild?
0:18:19 > 0:18:24- They do look rather large. That's - the dominant one in this group.
0:18:25 > 0:18:28- It has a white tail - - I like the white tail.
0:18:28 > 0:18:31- It's a warning - if they lift their tails.
0:18:31 > 0:18:33- To the others, yes.
0:18:33 > 0:18:35- They all have a white tail.
0:18:36 > 0:18:40- When there's danger, - they lift their tails and race away.
0:18:41 > 0:18:43- It's a warning to other rabbits.
0:18:43 > 0:18:47- They all stay close to each other.
0:18:47 > 0:18:51- The first journey out of the warren - is a success.
0:18:51 > 0:18:54- They've learnt - a valuable lesson about survival.
0:18:55 > 0:18:58- The rabbits aren't the only ones - ready for adventure.
0:19:12 > 0:19:17- The water voles were born much later - than the badgers and rabbits.
0:19:18 > 0:19:23- They've developed quickly, leaving - their homes after a fortnight.
0:19:23 > 0:19:28- One of the voles hasn't developed - as quickly as the others.
0:19:38 > 0:19:41- This one hasn't put on - as much weight as the other.
0:19:42 > 0:19:44- This is a cause for concern.
0:19:44 > 0:19:47- It's time to see - if it's ready or not.
0:19:48 > 0:19:52- Today, they will leave the burrow - and swim for the first time.
0:19:54 > 0:19:58- Having looked out of the tunnel...
0:19:58 > 0:20:01- ..this water vole - faces a new challenge.
0:20:01 > 0:20:06- It searches its habitat before - swimming for the first time.
0:20:11 > 0:20:17- These two enjoy playing together but - one of the little ones is missing.
0:20:18 > 0:20:20- There's no sign of the smallest one.
0:20:22 > 0:20:26- It's eager to join the others - but it's still unsure.
0:20:32 > 0:20:36- After eating some food, the little - one ventures to the water's edge.
0:20:36 > 0:20:39- It's not as confident - as its brother and sister.
0:20:56 > 0:21:01- Even though it's happy, it hasn't - learned how to get out of the water.
0:21:01 > 0:21:03- Its mother is on hand - to offer some help.
0:21:04 > 0:21:07- The father cares far less!
0:21:13 > 0:21:17- These water voles have made the most - of their fortnight in the burrow.
0:21:18 > 0:21:20- They can burrow and swim very well.
0:21:35 > 0:21:41- We've had the results - of the TB tests back.
0:21:41 > 0:21:47- Unfortunately, one of the animals - we have here has TB.
0:21:47 > 0:21:49- That animal has been put down.
0:21:49 > 0:21:52- On a positive note, - all the others are clear of TB.
0:21:53 > 0:21:58- They will go one step further - as they are returned to the wild.
0:22:01 > 0:22:06- We've learnt many new things - over the past fortnight.
0:22:06 > 0:22:10- We've seen water voles - growing incredibly quickly...
0:22:11 > 0:22:16- ..we've seen a mole feeding, - and storing worms.
0:22:16 > 0:22:20- We've seen badgers - learning how to burrow...
0:22:20 > 0:22:24- ..and the importance of smell - to their social lives.
0:22:24 > 0:22:28- We've also seen little rabbits - creating a close community...
0:22:29 > 0:22:32- ..before venturing out - into the wider world.
0:22:32 > 0:22:35- But the burrowers have a lot - to teach us again.
0:22:36 > 0:22:39- Next week, - we discover how the animals cope...
0:22:39 > 0:22:42- ..with the vast numbers - that are born each year.
0:22:43 > 0:22:47- How will the water voles adapt - to life outside the burrow?
0:22:48 > 0:22:51- A look at our badgers developing...
0:22:51 > 0:22:56- ..and Ceri and I visit - the rabbits on Skokholm Island.
0:23:23 > 0:23:26- S4C Subtitles by Adnod Cyf.
0:23:26 > 0:23:27- .