Horizon (1964) s52e08 Episode Script

The Secret Life of the Cat

The thing I love about cats is that they're very independent, but very loving.
You can play with them.
They're comforting.
They're furry.
If he's out, I get lonely.
When he's in, fine, I'm all right.
Well, you can see how lovely it is to have him near me and be able to stroke him.
We may love our cats, but how much do we really know them? They have a secret life that remains a mystery.
With leading cat scientists, Horizon has set up an experiment to find out what they get up to.
Wandering round.
Go back.
Go back a bit.
Across the week, 50 cats in this village will be put under 24-hour surveillance.
Good boy! Are you wanting to go outside and we can see what They'll be wearing specially designed cat cameras to show us what they do when they're not at home.
And carrying GPS receivers to reveal their secret journeys.
What's unique about this experiment is that it reveals how 50 cats live, crowded together .
how they hunt and fight Really a classic stand-off.
and the surprising strategies they use to get along.
It raises the intriguing possibility that our cats may be changing and that could be down to us.
I'm going to find Shamley on the map for us.
John Bradshaw and Sarah Ellis are two of Britain's leading cat scientists.
It should sweep round to the right.
They're on their way to the village of Shamley Green in Surrey to recruit cats for the study.
I think one of the things that will be really interesting about this study is, it's every owner's dream to find out what their cat does as soon as they go through that cat flap.
Well, let's hope it's going to betheir dreams are going to be satisfied, it won't be a nightmare.
The cat sniffing into the butcher's next door and stealing sausages.
There are over ten million cats in the UK and the highest density of them are found here, in the southeast of England.
But despite their popularity, scientists know surprisingly little about their behaviour once they've left the cat flap.
Got a fairly wide range of types of housing and, hopefully, types of cat here.
Yeah, definitely.
The built-up area, if I'm looking at the map, seems to be behind us.
And then these houses in front of us look to back all on to fields.
They want to find out more about how far cats travel each day So hopefully we'll get cats roaming out of their back gardens and up into the farms.
how these solitary creatures manage to live side by side I'll expect some of these houses in this more built-up area, there might be multi-cat households.
and where cats really find their food.
I've really been interested in the cat because it's that combination of wild animal and domestic animal, and the changes that are going on within it, that I find fascinating as a biologist.
The scientists are looking to recruit 50 cats of all ages, sizes and breeds.
I've got three cats, if that's any good! I've got one.
On average, cats live to about 15 and weigh in at around four kilos.
This is Lily.
She's an 18-month-old Bengal that I bred.
This is Obi, short for Obi Wan Kenobi.
This is Kato.
Claude's quite a character and he has various girlfriends in the district.
Does quite a lot of hunting.
I want to find out where he gets them all from.
That's what I said.
They go out every night and come back and sleep all day, so it'll be quite interesting to see how far they go.
My husband thinks he just goes ten feet up the woods, but I think he goes a lot further.
He used to belong to a lady over the road, but he left home.
They've now got a dog.
Everyone's gathered in the village hall to meet the scientists and find out more about what the study will involve.
We want to get a picture of your cat's natural, normal life, so don't do anything different, don't change your routines, don't lock the cat flap, don't suddenly call up the local handyman and get a cat flap put in.
Let the cat do what it usually does and hopefully we will build up this picture of what it's like to be a cat in Shamley Green.
I'll now hand over to Alan, who is the technical expert, among many other things.
Alan Wilson's task is to devise a new way to track the cats.
He's a world expert in tracking wild animals.
Where we do most of that work is in Botswana, in Africa.
So we design and build things like this.
This will fit on a lion.
LAUGHTER This will fit on a cheetah The technology that Alan has developed for the big cats is an advanced GPS tracker.
It tracks the animal's position, speed and how fast they're accelerating, step by step.
The collar has got solar panels on the top, it's got electronics in the top here and then the batteries on the bottom, and a radio antenna.
So this will give us the position of our animals to tens of centimetres, 300 times a second, and how fast they're going, so we actually get exquisitely fine detail about what they're doing, where they're moving, what terrain they're moving in, how they're hunting, when they're successful and when they aren't.
It really is opening up whole new measurements that weren't possible before with traditional tracking collars.
The information he's gathered has transformed our understanding about how these fearsome predators live in the wild.
We're going to turn on the GPS loggers.
He now has to do the same for our pet moggies by miniaturising his technology.
And today, he's testing it out for the first time.
This is Zach, this is my dog.
Zach's quite an expert on testing our collars for us.
Here's one of our wildlife collars that we're using in Botswana.
We've developed three smaller GPS modules we want to try on the cats.
And we can then compare the performance of those and see how well they work, compared to what's our gold standard, which is our wildlife collar.
I think it's going to be quite I think they're going to object to it a lot more than our wild cats do.
And they're a lot smaller, so the size of the collar is much And, yes, I don't think it's going to be easy.
Here, at the Royal Veterinary College, Alan Wilson's colleagues are developing a cat-tracking system that is accurate to within centimetres, incredibly lightweight, so the cats will wear it, with a battery life that will last 24 hours.
Zach, come! Cats are known to travel up to 31mph, often under the cover of trees and undergrowth.
So Alan now has to analyse his data and choose a tracker that is robust and accurate enough.
And here it is.
There are 50 of them, and the owners are queuing up to get their hands on one.
Fantastic! Give her another stroke.
Excellent, and let her eat.
Have one of these.
More food for him? Amazing.
Within a few days, we've got 50 collars on 50 cats.
Everything is now in place for the study to begin.
The scientists are setting up base in the village hall.
The operation will run day and night, across the week.
They've brought in an undercover surveillance crew so they can secretly film the cats.
We're having five more cameras dotted around.
One on top of the garage.
So hopefully, we'll be able to see what's going on.
With the technology in place, it's now all down to the cats.
The scientists arrive at the village hall, just as the first day's GPS data is coming in.
301, 302, 303.
Alan's team of engineers have worked through the night, wrangling the data and finding a way to visualise the cats' precise movements over 24 hours.
This is our village green here.
The deli's here, isn't it? Or here.
A detailed picture of the cats' first 24 hours of activity now starts to emerge.
Have you seen this one? It's quite exciting.
Each cat is represented by a different trace.
Brutus, who simply patrols around his home.
Molly, who's drawn to the neighbouring wood.
And Ginger, who heads out to a neighbour's house.
The first question is, how far they travel beyond the cat flap, which is what scientists call the cat's home range.
Sooty, who lives on the edge of the village, grabs everyone's attention.
It's quite a big range.
What do we know about Sooty, John? OK, so Sooty is an ex-farm cat, so that would figure.
Sooty has walked two miles in the first day, but he's gone just 160 metres in each direction from his home.
Sooty's really covering about three hectares.
He tends to travel quite a range in this one particular time period.
But Sooty is unusual.
In the heart of the village the average male cat goes just over 100 metres from his house, and female cats just over half that.
Some of our cats that lived in this much more dense area, actually how far they went was much denser, was much closer, wasn't it? So the cat density is probably much higher here than it is here.
And we've got a much wider roaming on this particular day.
Another thing that's clear is that these cats seem to have distinct patches that they roam in.
Some areas of the village which apparently aren't being used by the cats, but then it may not be, of course, a typical evening.
One day.
Not the greatest of weather.
So the secret world of cats happens close to your back door, just out of sight.
Even if they don't go far from the cat flap, they are still busy patrolling round and round the same area.
Which do you think is the one who's travelled furthest? I think Sooty's the one who's done most walking around.
What we're seeing here on the screen is the very first indication we've ever had of the detail of the pet cat's life when it's outside the home.
Billy's travelled on this excursion up to the farm and back, but looking at Sooty, Sooty may not have ranged quite as far but there's a lot more loops here.
I think the fact that we have got 50 GPS collars on cats in this village is fantastic, because one cat's behaviour will influence another's, undoubtedly, when they're sharing the same physical space.
Thomas is active nearly three times - a little bit after dawn and then in the early afternoon and then a big burst of activity in the evening, 10, 11 o'clock.
Quite a rush to get to this point and so many things could have gone wrong, they don't seem to have done so so far, so I'm really pleased, really excited about what we're going to see over the next week and what data we'll get.
It'll be nice to see as we go over the whole week whether we see any usage in areas we're not seeing Oh, yeah.
So what are the cats actually getting up to when they're out on patrol? In order to find out, the BBC's research and development department has created a new type of camera that will capture a cat's eye view of our world.
Today, Dr Sarah Ellis and Alia Sheikh, who developed the camera, are out to test a prototype.
I wonder if that's recording.
Oh, I see, that's clever.
Is it recording? It's recording now.
Is it? It is.
The cat's welfare is the first priority.
The cameras are very light, and will be fitted onto quick-release collars in case they get caught up.
He's a good boy! We'll give him a bit of fuss, that's lovely.
And we'll play with him.
There's a good boy, such a good boy.
You're a good boy! Are you wanting to go outside and we can see what you're doing with that camera on? The cameras are then made smaller, able to film in the dark, even record sound .
and then connected to the GPS collars so that we can see exactly where cats are and exactly what they are looking at.
We've chosen 14 cats to put cameras on, and soon the world through their eyes starts to unfold.
Hello, Coco.
How are you this morning, hey? Yes.
Cats have excellent long-distance vision, but they can't focus their eyes under 25 centimetres, which is why they have whiskers.
They can jump up to seven times their own height .
and jump down much further.
So far, the experiment has revealed just how close to home most of the cats in the village stay.
But as everyone knows, when cats stray into each other's areas, trouble begins.
GROWLING AND HISSING For some cats, the privet hedges and gravel paths off our back gardens are a battle ground.
There was one cat that came into the garden.
It wasn't so much a fight, it was a showdown between the two of them sort of staring at each other.
He was out all the time, he was like the king cat of the close, and he was always fighting and literally no-one would come Any other cat would be, like, "Oh, it's Kato.
" I heard this tremendous fight going on, so I got the ladder, climbed up the hedge to see what was going on, and the cat was having a fight with the neighbour's cat on top of the hedge.
On top of the hedge? That was Scarface? Scarface.
He does come in occasionally, frightens the life out of them.
Charlie runs up the stairs to hide.
Scientists think that many cats have a territory much smaller than its home range.
It's territory is its own personal space where it eats, sleeps and rears its young.
When another cat enters this space, they instinctively want to defend it.
CAT MEOWS One of the questions for the scientists is how cats establish and defend these territories.
Ginger has lived in the village for ten years, and seems to be a pretty placid, well-behaved cat.
We think that he just goes next door, catches the odd bird, and sleeps.
We don't think he goes out at night, because when you watch him, he doesn't seem to like getting or being out in the rain or he doesn't like the cold, In the summer he'll just sit and sunbathe in the garden, so, yes, it will be interesting.
But appearances deceive.
Ginger, it turns out, has a secret life.
Here's Ginger, he came over here and if we just move forward.
The GPS data shows he's making a deliberate, provocative journey into another cat's garden.
To see what he's up to, the scientists put a camera on him.
At 8.
36pm Ginger leaves the house.
He spends a few minutes patrolling his own back garden.
Then takes a trip across the village common.
At exactly 8.
48pm, Ginger stops dead in his tracks.
Just as he's entered the other cat's garden.
And that cat is at home.
HISSING AND GROWLING YOWLING Eventually Ginger makes a run for it.
HISSING If you want to come in and have a look, we've got some footage that's This is from Ginger, and Ginger's been roaming around the area near its house, going through some fields.
Moving quite fast.
He's stopped.
You can see right away there, there's a pair of eyes from another cat.
HISSING GROWLING He's running towards the other cat.
I think he's trying to get a bit of distance, really, more than anything, because the other cat came towards him.
Definitely doesn't want to be anywhere near him anyway.
Wow! That's OK.
It looks like really a piece of classic stand-off between two cats, where they are using hissing, growling and yowling to really try and keep a distance from each other.
And it looks as if it was reasonably effective there.
And this is Tigger, the cat whose garden he was in.
She lives in the house on the other side of the common.
Didn't hear anything last night.
We do hear fights on occasions but I didn't hear anything last night.
I'm surprised, actually, because I always thought No, she doesn't.
She does fight.
So this is how cats establish, defend and even expand their territories.
Our night-time pictures reveal that these stand-offs are going on all the time.
GROWLING But although they found this happening over and over again, rarely did it lead to fighting.
They are descended from a solitary species, so if they blunder into one another, then it's very difficult for either of them to back down, because turning your back on another cat is a dangerous thing to do, and most cats will have learnt that very early on.
They would actively defend a piece of land which contains their core resources.
Cats do sometimes actually fight.
There are actual wounds, claws and teeth get used.
But most cats will tend to try and avoid conflicts because if you rely on yourself for survival, it is not good in terms of fitness to get yourself injured.
It's incredibly costly.
So this is a big part of what your cat does beyond the cat flap.
Patrolling and facing off the neighbours' cats .
but, above all, trying to avoid a scrap.
Big Ginge.
Big Ginge! Pebbles with a hat on, looking quite cross.
The way they avoid fighting isn't just by having stand-offs.
The scientists think there's something intriguing happening, where the cats' spaces overlap in the middle of the village.
This is Phoebe, she's been living here for six years.
And this is Kato.
He's been here even longer, and his owner wants to find out why the two cats have become permanent enemies.
He's got enemies across the road.
And do you know who that is? Phoebe.
Phoebe, OK.
Sarah thinks that she may now have the answer.
The GPS data reveals this is what Kato gets up to over 24 hours as he travels around the cul-de-sac.
And when you put Phoebe's trace on the screen, you get a snapshot of HER daily routines.
So, in the green, huge amount of overlap in the space that they use.
There is, isn't there? For cats, which seek their own space, these two cats are on top of each other.
No wonder they are stressed.
But they don't seem to be fighting much.
So what's going on? It's 11.
50pm, here's Kato heading out on his night patrol.
He stays mostly around the cul-de-sac, and takes a trip into the local woods.
He comes back around dawn.
An uneventful night.
And that's because Phoebe hasn't left her home all night.
But at 7.
45 in the morning, Phoebe heads out on HER patrol.
And Kato, he's at home.
Watching nervously.
A deeper look at the data suggests that the two cats may be sharing the same space, but not at the same time.
Kato's out a lot, Kato's out a lot late in the night here, and a few short forays in the morning.
Phoebe's active during the day, and mainly after lunch, Not much overlap in when they're outside.
So when one was active outside, the other wasn't.
So we think what they're doing is Avoiding each other.
Using a shift system, and the occasional time when it doesn't work, that's when you're getting a fight.
Right, OK.
So it's nice to know that they have got the shift system and they are managing themselves.
And it's not just these two cats.
Other cats, like Billy and Molly Interesting.
Molly is out at one, two o'clock in the morning, a lot of activity here in the early morning, when Billy wasn't out.
One's going in, one's going out.
and Claude and Thomas seem to be doing the same thing.
Claude comes over into the area of Thomas, Thomas is much further over, they're not in the same place at the same time, they may time-share that area.
It seems to be happening all over the village.
And here's how they're doing it.
A set of chemical signals and scents which are secreted from the cats' glands in their cheeks when they rub .
and from their paws when they scratch .
marks out who was where, and when.
If we imagine that the cat is putting down a Post-it note, it says what time it was there, who it was, and then it leaves that area.
Now, the nice thing about leaving a chemical signal is that you can physically leave, but you have left a message for another cat, so when that other cat comes along and reads that message, or that Post-it note, if you like, it's gaining information about who is using that space, and how long ago they were using it.
Sarah and John have believed for a while that cats time shift, to share space and avoid fighting.
But this data is the strongest evidence they've gathered so far that it's really happening.
The week progresses, and the data continues to flood in.
The scientists have been looking at how much time the cats spend outside the cat flap.
The proportion of time they spend outdoors is actually quite low, it might be as little as 20% on average, and some cats we know now don't go out at all.
Even though they have access to the outdoors, they just simply choose not to do so.
At any one time, there are many more cats inside than out.
Outside, the most we've ever really got is ten cats outside at one time.
There's a nice place to rest at home, they go out because they feel like it rather than because they need to.
So the next question to answer is, what has happened to the wild sides of the cats of Shamley Green? Cats haven't always been our pets.
We started living alongside them around 9,000 years ago, when we started farming.
And they had to work for a living.
We gave them food and shelter, in return for keeping mice and rats at bay.
It's the same reason these cats live on David Hicks's Oxfordshire farm today.
We were just overrun with rats and the poison wasn't working.
They were burrowing under the floors of the buildings, undermining the floor so the floor collapsed, making holes in the bags of food, and mucking and peeing in the food, making it inedible for the animals.
We had such a rat problem, in the end, a friend suggested we got some cats because they sorted his rat problem out.
We're three, four years on now, we've got lots of cats but no rats.
This relationship explains why it was beneficial for cats to hold on to their wild side.
Cats like these must live much in the same way as we imagine cats must have lived right at the beginning of domestication, when cats were first beginning to associate themselves with man.
These cats are really here as hunters, they are here to keep the rats and mice down on this farm.
And in that respect, they behave much like wild animals, they use the same hunting tactics that wild cats do, and every cat still has within it the instinct to go hunting.
Cats are undoubtedly much wilder than the average domestic animal is.
They choose their own mates, who is going to father which kittens, rather than, as with most domestic animals like sheep or cattle, or whatever, it's the farmer that makes the decisions.
Cats are still really in charge of their own destinies.
And whether they do become our pets is down to how they are reared as kittens.
There is really a very short window of opportunity during which kittens can learn about how to socialise with people.
It's just between about four weeks of age and eight weeks, which is considerably shorter than other domestic animals.
So if a kitten doesn't meet people within that first eight weeks then it essentially goes feral, it becomes an animal which is more or less like a wild animal.
It's still got the domestic genes in it, but it is, in terms of its behaviour and its attitude to people, much more like a wild animal.
This ability to tolerate humans yet hold on to their wild side was crucial for the domestication of the cat.
Even if we think we've managed to domesticate cats, they still retain their wild sides.
And that's because cats remain natural born hunters.
They're often vilified for killing off other animals.
But the extent of this predatory behaviour, in the UK at least, is uncertain.
We found this mole here this morning and we don't know if Ginger caught it or not, but it's dead, so we're going to pop it in here.
Pick him up so we can take him up to the hall tonight and they can have a look at him up there.
The scientists are hoping to use this study in Shamley Green to see if there are any clues as to what's going on.
It's a little shrew, from Phoebus.
And he caught it a couple of nights ago.
We've ask the owners to collect everything their cats bring home throughout the week.
Lovely! It's been in the freezer for one night.
Probably died of old age.
I think he's been around the gardens for ages.
Because cats usually hunt out of sight, often under the cover of night, the scientists are hoping the cat cameras and GPS collars may help reveal what they are up to.
When I came down this morning, I opened the back door and on the mat outside was this.
On the back lawn, was it? Yes, on the back lawn.
Think it's a bird.
He walked in very nonchalantly, looking very satisfied, so I went out and had a look, and all that was left was one eyeball.
This is the green.
That's the green over here, this is the other side of the road.
John, Sarah and Alan have started combing through the cats' traces to look for unusual night-time activity which may indicate hunting.
So that's Billy, and he looks like he's travelling up to a farm or a single household, one single trip up and back down.
This is another cat that he lives with, is it? Molly's from the same house as Billy, they're both British Blues, pedigree cats.
This big trip is at night-time.
So I guess he's going to be hunting up that hedgerow.
What he was doing at the farm, of course, we don't know.
They were right to suspect hunting that night.
Billy and Molly's owner has seen the cats the following morning.
I think they were out pretty well most of the night, actually.
I'm pretty certain they went out as soon as we went to bed.
Billy in particular came in with a very bloated tummy, so I don't know quite what he's been up to, but probably eaten quite a few bits and pieces along the way, and he's very sleepy today.
In fact, both of them are very sleepy, so I think they've been hunting a lot last night.
They start to identify the cats that seem to have the strongest indications they've been hunting.
Like Sooty.
Spends quite a lot of periods of time there.
Backwards and forwards and backwards and forwards, suggesting he may be using that as a bit of a hunting ground.
A lot of time and a lot of movement in that area before he comes back down.
So this is very much a journey, whereas this would be more suggestive of hunting-type just because he's covering the same area a lot.
The next night, the scientists put a camera on Sooty.
At night, cats' eyes only need a sixth of the light And what helps them hunt is they can hear a broader range of sounds than almost any other mammal.
He appears to be looking for something in a tree.
But tonight, Sooty is not successful.
The pub cat, Chip, spends a lot of time in her neighbour's garden.
And here's why.
He climbs a tree to get into a hedge .
where there's a bird's nest ready to be plundered.
The camera falls off so we don't see the aftermath of his attack.
But we do have the evidence.
So by the end of the week, John wants to know how many birds and small animals the cats have brought home.
And what, if anything, it tells us about the true nature of their hunting abilities.
We've got about 15 items here, brought in by the cats, which the owners have managed to collect.
The owners have also told us that there was probably seven or eight other things but have been consumed in front of them, so a total of just over 20, divided up between 50 cats, so that's less than half a prey item per cat over the whole week.
It's not a huge amount.
I don't think our cats are hunting very seriously.
They obviously spend a lot of time out of doors, or at least many of them do, looking around, as if they're hunting, but the actual pouncing attempts are comparatively rare.
There's a couple of birds actually been eaten, at the back here, a house mouse, just one, which is the traditional prey of the cat.
That's a vole, and here, almost in pride of place, is a mole, which is very difficult to catch for a cat, because of course they spend a lot of time under ground.
This is no more than a snapshot of what's going on over one week in this village.
But while we've been here, the impact has been rather minimal.
So what might be going on here? It could be that this year's cold spring has delayed the birth of the baby animals.
Or that cats just don't like being outside in bad weather.
But the data from the experiment has thrown up an even more intriguing possibility.
When Coco's GPS collar is first turned on, she's in this house, and it's not hers.
On Tuesday, here's Chip.
Again, he enters a neighbouring house.
And a day later, here's Claude doing the same.
It's only when we install surveillance cameras by the cat flaps that we see exactly what is happening here.
Rosie has her evening meal.
And then half an hour later, her neighbour, Claude, boldly enters her home and helps himself to the leftovers when she is out of the way.
At 3pm the next day, he's at it again.
And it won't be the last time.
It's a bit of a surprise to Claude's owner.
Three minutes of scoffing in Rosie's house, non stop.
How embarrassing.
We've watched this video several times, and he doesn't spend much time lifting his head, looking around.
Worrying about anything.
He's at home.
This is normal.
I feel that he's confidently doing this, and so he's done this probably more than once, this may be routine for him.
Oh, dear.
So, yes, midnight snacking is definitely happening I think one of the things that I've been surprised by has been just how many cats are going into other people's houses.
I'm not sure yet quite how many of those people are aware that those cats are coming in, but one of the main reasons they come in will be to get food.
They'll be stealing food from other cats, essentially.
I think you can almost bounce that off against the rather small numbers of prey that we've seen this week.
Some of that may be down to the weather, but I think a lot of it is these cats are getting a varied diet by raiding other people's houses, they don't really need to go out and kill things.
Over the past decade pet food has become more nutritional and more common.
So perhaps what we are witnessing here is cats changing their behaviour as we change their environment.
But there's another part of the cats' secret life, where they've adapted to being more like our pets, and it's to do with how they communicate with us.
This cat meows a lot.
They both purr.
If he's got no-one to play with and he's just on his own, he'll walk around - meow, meow, meow, meow - until someone comes.
Sometimes, I can hardly hear it.
this sort of thing.
He does have various purrs, yes.
We may think cats are our pets, but many owners are left with the uncomfortable feeling that the cats are really calling the shots.
We tend to fit in with the cat's lifestyle.
Very much so.
The cat's in charge? No doubt about it.
It probably makes us quite unique, in some respects.
Do you reckon? I reckon, most households, I think the cats are in charge.
Not quite as much as this one, I don't think.
This is very much a feline-focused family, we are.
By his purrs, I know more or less what he wants.
They get their own way because as cats have become domesticated, they've learnt to change the way they communicate.
When an animal meows or purrs, we tend to verbalise back to that.
And it's almost like we have this idea of there being a conversation.
And I think that definitely does have a part in strengthening the bond.
Sarah Ellis is going to repeat an experiment first conducted at the University of Sussex on her own cats.
It focuses on two different types of purr.
She's going to record them to find out what makes purring such an effective way for cats to get our attention.
The first is the non-solicitation purr.
GENTLE PURRING The non-solicitation purr will be the one that people are most familiar with.
That's the purr that cats do when they are content, relaxed, when they're being stroked or interacted with by their owners, or if they're sitting on your knee, for example.
In you come, good boy.
But scientists are particularly interested in another type of purr, the so-called solicitation purr.
Cat owners will definitely be aware of this, but it may not be so well known amongst non-cat owners, and this is the purr that cats do when they want something from their owners, and very often that is in anticipation of food or if you're preparing food.
LOUDER PURRING It's constantly chopping and changing the length of those purr bouts.
And the purr is much faster in certain parts, isn't it? Back at the lab, Sarah's colleague examines the frequencies of the purrs.
At the top, we've got the solicitation purr and down below, we've got the non-solicitation purr.
Both of these are low-frequency purrs, but what particularly stands out quite clearly is that complete stand-out peak you can see with a solicitation purr.
It's very isolated from the other frequencies around it, which suggests it would really stand out quite clearly.
You don't see that at all in the non-solicitation purr.
And there's a surprising reason why we react so strongly to this frequency in the purrs.
Because embedded within it is the same frequency as a baby's cry.
As humans, we are more sensitive to vocalisations and we're more likely to respond to them.
And that's likely because it taps into and it's this, I think, that makes them so successful at being our pets, because they have to illicit care-giving from us, and they've become very, very good at that.
The experiment is drawing to an end.
The scientists are starting to see the ways in which cats' behaviour is shaped by us, and by all the other cats living so close by .
how they've created tightly packed territories Todd came up here, really close to where Thomas has been.
how they may be time-sharing to avoid fighting .
and how they may be hunting less and eating each other's food.
But there's one surprise left in the village.
This is the Edwards' house.
And they have not one but six unrelated cats living together.
Meet Duffy, Patch, Daisy, Coco, Pumpkin and Ralph.
They seem a pretty happy lot, and given that the cats are both solitary and territorial, they do seem to get on pretty well together.
But no-one is sure what happens beyond the cat flap.
Yellow's Daisy.
What colour is Pumpkin? Pumpkin's pink.
Coco is red.
So while Patch roams the local neighbourhood, Duffy, Daisy, Coco, Pumpkin and Ralph are all out at the same time and sticking very close together.
Which is a genuine surprise.
Your cats are actually really interesting.
Down in the village, we've got lots of reports of hostility, including fights, and in a multi-cat household, which you have, you're our largest number in our study, with six cats, we would expect there to be quite a bit of tension, quite a bit of using different space outside.
What's really, really unusual is we don't see that with your cats at all.
And apart from Patch, who is the blue, and he does have a further range, he does go much further than the others, they're very, very much centred around your home, around your garden, and the really interesting thing is, they're all there at the same time.
None of them are moving particularly quickly, they're all just bumbling around together, really.
That, for us, is fascinating, because a whole group of unrelated cats we just wouldn't necessarily expect that at all.
Out of all the lot we've had, this has been the ones that have gelled the most.
Especially the boys, they're always You'll see them playing together, they will lie together.
Pumpkin and Ralph lie on top of each other, not just next to each other.
It's so cute the way they get on so well together.
Do you ever see them rubbing their faces against each other? Yes.
And Pumpkin and Ralph spent a lot of time grooming each other.
This cat camaraderie is another example from the experiment to suggest that cats may be changing, evolving away from hunters to fit in better with us.
As we're domesticating cats, we're retaining a lot more of what we call their juvenile characteristics.
So they purr a lot, they play a lot, we see them needing behaviour.
With our pet cats, if we are domesticating them and they are evolving, in a sense that they are retaining lots of these characteristics, they might be more likely to be able to get on with each other.
But we're right at the cusp of that, in sort of the domestic cat's evolution.
If she's right, this sort of feline harmony could be a vision of the future, as cats evolve to please the hand that feeds them.
At the end of the week, the team have pieced together a picture of what the cats of Shamley Green get up to when they leave the cat flap.
Look, she's gone so far! The scientists have seen that all the cats have very different routines and roaming patterns.
One of the most stay-at-home cats is Brutus.
Didn't think he did, but now I've got the proof he doesn't go very far, so that's reassuring.
And Hermie is definitely our roamer of the week.
From the top to the bottom, that's 300 metres, it's 200 metres across, so that's six hectares, 15 acres which he's actually ranging over, he's really going a long way overnight, Quite exciting.
I had suspicions he may have found himself a sofa in the village that he likes to sit on, but evidently not.
The remarkable thing about this study is its sheer size and the accuracy of the data.
Because we're looking at 50 cats, you can start to look at a lot of different effects in the data which you just don't get with a smaller study So this has come together really nicely to give a dataset that's a size that you can actually And what the scientists are seeing is a community of cats The cat, when it goes through our cat flap, exhibits some of the behaviours of its wild ancestors, such as hunting, and then it will come back through our cat flap and have a social bond with the owner and be a family pet.
Cats are still evolving and probably will still evolve into the future, becoming much more pet-like animals, and will lose some of those wild instincts because many of those things don't actually serve them very well Perhaps cats will become less wild and even more pet-like, because that, it seems, is what we want them to be.
And if you want to follow more of our cats' journeys you can log on at MUSIC: "The Pink Panther" Theme Tune