Under the cover of darkness, Claude slips through the back door of an unknown home and enters the kitchen.
As its unsuspecting owners sleep inside, the intruder pads over the terracotta flagstones with barely a sound.
He knows what he is looking for and he knows how to get it. He’s done this before. But it isn’t jewellery or electronics that Claude’s after – it’s food.
Scroll down for video
Lilly the cat at the BBC's feline HQ in Shamley Green, Surrey. Lilly is one of the stars of BBC's Horizon documentary, The Secret Life of the Cat. The makers of the show fitted 50 cats with highly sensitive GPS collars and miniature 'cat cams' that recorded their every move
When the cat's away: The BBC Two show followed 50 cats like Thomas, pictured, around the leafy Surrey village of Shamley Green during one week in April
Because Claude isn’t just any old burglar. He’s a cat burglar – quite literally.
An eight-year-old grey and white tom, he likes chasing mice, sitting in the front garden and Whiskas cat food – which he regularly steals from the bowl of his neighbour’s moggy, a five-year-old ginger named Rosie, once her owners have gone to bed, by making full use of their cat flap
Despite owning Claude for seven years, having adopted him as a kitten, Henrietta Mulnier, a 47-year-old lecturer, was unaware of his nocturnal thieving (which, as it turns out, is surprisingly common among domestic felines) until recently.
‘I had no idea,’ she laughs. ‘I’ve always wondered why he never seemed to lose weight even when I put him on a diet – now I know.’
It’s only thanks to a fascinating experiment – the results of which can be seen in Horizon: The Secret Life Of The Cat tonight on BBC Two - that Claude’s light-fingered ways have been revealed.
Dr Sarah Ellis, far right, shows the cat owners where their pets travelled during the one-week surveillance. Each cat's route was tracked and mapped onto a large screen at the BBC's Surrey Cat HQ
The programme documents how, for one week in April, 50 cats in the picturesque Surrey village of Shamley Green were put under 24-hour surveillance, fitted with a highly sensitive GPS collars and miniature ‘cat cams’ which recorded their every move.
The results will fascinate millions of cat owners – including, no doubt, George Osborne, whose tabby Freya was discovered by neighbours last year after disappearing for more than two years.
The absence, combined with her habit of wandering Whitehall’s corridors of power after she turned up again, has prompted some within the Government to warn that she could be working as a spy.
‘Before, we really didn’t know very much about what cats get up to,’ explains Dr John Bradshaw, an expert in human-animal interactions at Bristol University, who led the study alongside Sarah Ellis, a cat behaviourist at University of Lincoln’s Life Sciences department.
Each cat was fitted with a GPS collar so the researchers could track their movements. This map shows the data collected from three of the cats in the vilage. Claude's trek is shown in red, Deebee's is shown in blue, and Thomas' is the green lines
‘They’re fascinating creatures because they are part-wild and part-domesticated.’
They chose Shamley Green, he says, because of the high concentration of domestic moggies.
It didn’t take long to find 50 willing cat owners among the village’s 600 residents.
John says: ‘We put posters up in local shops and spoke to people in the street. Word spread. A month later we had a meeting in the village hall – almost every other cat owner in the village was there.
‘People were just very intrigued. They have this life with their cat but have no idea where it goes. All cat owners would like to find out what their pet gets up to.’
The tracking system which John and Sarah used was designed by experts at the Royal Veterinary College, based on technology used in Africa to track wild cats.
An interactive map created by the BBC lets you follow 10 of the 50 Shamley cats featured in the Horizon programme including Ginger, Sooty, Orlando, Hermie, Phoebe, Deebee Kato, Coco and Rosie. Each cat's path was mapped using GPS collars and is shown in a different colour
Each moggy was fitted with a specially-designed collar which collected GPS data on their location and level of activity.
The scientists could then remove the collars and plug them into a central computer installed at their temporary headquarters in Shamley Green’s village hall.
If the GPS system showed interesting movement patterns, the cat in question would be fitted with a ‘cat cam’ – a tiny surveillance camera designed by specialists at the BBC’s research and development centre – which dangled from their neck as they went about their business.
Claude’s night-time raids on his neighbouring cat’s food bowl, meanwhile, were captured with the help of a hidden camera erected in the corner of the kitchen, after his GPS data showed he was entering Rosie’s home.
Even cats that don’t like wearing collars can be trained to use them,’ says John. ‘And we didn’t have too much of a problem with the cameras – apart from a couple which got lost!’
It wasn’t long before John and Sarah were picking up all sorts of intriguing tit-bits.
First, the cats’ movement patterns: despite disappearing from their homes for hours at a time, very few of the moggies ventured further than 50 metres away.
Instead, they stuck to distinct, well-defined patches – Claude may not have been concerned about sneaking into a neighbour’s kitchen, but he rarely strayed more than five doors down the road.
Under surveillance: Dozens of cats were fitted with GPS collars and minature cameras which recorded their every move
The only exception was seven-year-old Sooty, who roamed two miles a day over an area of more than seven acres.
‘We had always been curious about what he got up to,’ says Sooty’s owner, 17-year-old A-level student Tom Townsend-Smith, who lives in Shamley Green with his parents and sister. ‘He disappears for long periods of time – now we know why.’
Unsurprisingly, Sooty descends from a line of farm cats, accustomed to roaming for miles around.
As for the others – though they may not have travelled far, they were remarkably proprietorial about their territory, marking it with distinctive-smelling chemicals which are secreted when they rub up against trees and rocks.
Not that they were averse to the odd bit of territorial invasion themselves. Even the most placid moggies, it turns out, can turn into feline Napoleons come nightfall.
Mischievous moggy: Janet Williams, 50, was surprised to learn that her mild-mannered cat Ginger was in fact embroiled in a Cold Turfwar with another cat down the road
Janet Williams, a 50-year-old book-keeper, was surprised to learn that her mild-mannered ten-year-old tomcat Ginger was moonlighting as the local trespasser after she had gone to bed.
‘We’d always thought he was quite a laid back cat. He might go next door or something, but no further than that.’
In fact, Ginger was making regular 4am trips into the garden of another cat, Tigger, further down the road – much to Tigger’s dismay.
CAT CAMS: THE SCIENCE BEHIND THE SURVEILLANCE
The research was carried out by Professor Alan Wilson and his team at the Royal Veterinary College, London who have been developing wildlife tracking tags and collars.
These collars feature high-accuracy GPS and electronic sensors that record the activity and movement of animals ranging from pigeons to big cats.
Wilson recently used the collars to study wild cheetahs in Botswana and were able to see when they are active and how far they range.
The team also discovered how often they hunt, how often they make a kill and new information about their athletic capabilities.
However, he added no-one has ever applied the same study methods to domestic cats.
The biggest challenge for the team was to make the tracking equipment - the GPS and activity sensor tags - small and light enough for domestic cats to wear around their necks on safety-release collars.
Describing his involvement in the study, Wilson said in a blog post: 'GPS uses a lot of power, but we could only use a small battery, so in order to save energy, we used an activity sensor to trigger the GPS only when the cat was moving.
'This also saved us from collecting a lot of uninteresting data on sleeping cats.'
Each of the collars also had a small radio transmitters fitted meaning the team could track the collar down if it fell off.
Once the smaller collars had been developed the research team set up Cat HQ in the Shamley Green Village Hall.
Wilson said that being on site enabled his team to examine the data as soon as it came off the collars, and to work closely with behaviour specialists Dr Sarah Ellis, of the University of Lincoln, and Dr John Bradshaw, of Bristol University.
For example, the collar data helped Wilson to decide where to place fixed cameras by identifying activity hotspots.
The data also told his team how active each cat was, which helped them choose which cats to fit with the 'cat cam' collars.
The team could also discuss the findings with the cats' owners.
Once Wilson processed the GPS and activity data for the cats his team used specially designed computer software to lay the cat tracks on top of aerial photographs from Ordance Survey.
Since the programme was filmed, Wilson said he has have collected more data from the village cats and the results will be published in a scientific paper.
VICTORIA WOOLLASTON
The two cats’ ‘cat cams’ show them squaring up to one another, their blurry forms illuminated by the cameras’ in-built infrared torch. Circling one another in a kind of feline Cold War, neither moggy wants to make the first move to attack.
Instead, after much hissing, Tigger retreats.
Says John: ‘We saw stand-offs but not very much fighting at all.’
So if they’re not scrapping – how exactly do the cats go about protecting their territory?
The answer is with the help of a sophisticated shift system. Though the GPS data showed that the paths of Shamley Green’s felines did, at times, overlap, it also demonstrated how each individual moggy avoided getting into unwanted confrontations by venturing out only within strictly-defined time windows.
Cat routines: Kato, pictured in 'his' garden wearing a cat cam, would only leave house when the neighbour's cat had vacated the streets
50-year-old courier Debbie Harris, who has lived in Shamley Green for more than a decade, has long wondered why her nine-year-old black-and-white tom Kato only ever seemed to leave the house just as Debbie was going to bed.
It wasn’t until his roving patterns – which saw him patrol half a mile around Debbie’s house every night at the strike of 10pm – were compared with that of a neighbour’s cat, a six-year-old Tortoiseshell named Phoebe, that she discovered the answer.
While Kato ventured out in the street after dark, Phoebe stuck to daytimes, beginning her daily perambulations at 1pm on the dot – all the while under Kato’s watchful (and wary) eye.‘I’ve seen him sitting on the windowsill eyeing up Phoebe from afar, says Debbie. ‘I was quite amazed when I found out that they deliberately avoid one another. I wasn’t expecting it at all. It’s very clever of them.’
Watching: The 50 cats in Shamley Green were put under 24-hour surveillance shedding new light on the hidden lives of cats such as Paulina Bayliss' moggy Toby
Deebee is shown wearing her cat cam, being held by owner Julia Helby. Deebee is one of the newest cats in the village
The pair’s uneasy truce was a pattern repeated across the village where cats were living side by side.
John says: ‘Our GPS data points towards the other cats doing the same. The key to understanding cats is understanding their territory and their relationships. They are quite solitary really, so when you cram them together in a village, they don’t like each other very much. They are descended from territorial animals – it’s their wild legacy. We aren’t sure how the system develops but we think it’s from their routine of marking their territory with their scent.’
Scientists believe that, as well as being able to smell where other cats have been, they are able to tell how long ago there were there. In one cat had been in the vicinity recently, the other is likely to steer clear until more time has passed. Once the routine has developed, it becomes a matter of habit.
Another revelation was that, even when they were out and about, the cats of Shamley Green rarely went hunting for themselves. Over the course of the week, the cat owners were asked to bring in every bit of prey their pets brought home.
Aside from the odd vole or shrew, there wasn’t very much to speak of. Just 20‘kills’ by all 50 cats. Which may go some way in explaining Claude’s cheeky habit of pilfering his neighbour’s nibbles.
In his defence, Claude was far from the only light-fingered feline in the village.
Investigative team: Dr John Bradshaw, Dr Sarah Ellis and Professor Alan Wilson discover what cats are up to behind their owners' backs
During their week of surveillance, several others were caught sneaking into kitchens that weren’t their own for a late-night snack.
Tom Townsend-Smith was amused to hear that Sooty regularly sneaks next door for an evening bite: ‘It’s very cheeky of him – it’s like he has a second home.’
And Janet Williams was finally given an explanation for Ginger’s lack of appetite at home, when she found out that he had been filching titbits from the feeding bowl of an elderly female cat down the road: ‘She obviously had nicer food than we give him. It’s quite cowardly of him - picking on an old girl like that!’
So, next time your feline friend slips out through the catflap, give a thought to what he might be getting up to when your back’s turned. Burglary, territorial invasions, and carefully timetabled patrols – it’s all in a day’s work for the Machiavellian moggy.
As its unsuspecting owners sleep inside, the intruder pads over the terracotta flagstones with barely a sound.
He knows what he is looking for and he knows how to get it. He’s done this before. But it isn’t jewellery or electronics that Claude’s after – it’s food.
Scroll down for video
Lilly the cat at the BBC's feline HQ in Shamley Green, Surrey. Lilly is one of the stars of BBC's Horizon documentary, The Secret Life of the Cat. The makers of the show fitted 50 cats with highly sensitive GPS collars and miniature 'cat cams' that recorded their every move
When the cat's away: The BBC Two show followed 50 cats like Thomas, pictured, around the leafy Surrey village of Shamley Green during one week in April
Because Claude isn’t just any old burglar. He’s a cat burglar – quite literally.
An eight-year-old grey and white tom, he likes chasing mice, sitting in the front garden and Whiskas cat food – which he regularly steals from the bowl of his neighbour’s moggy, a five-year-old ginger named Rosie, once her owners have gone to bed, by making full use of their cat flap
Despite owning Claude for seven years, having adopted him as a kitten, Henrietta Mulnier, a 47-year-old lecturer, was unaware of his nocturnal thieving (which, as it turns out, is surprisingly common among domestic felines) until recently.
‘I had no idea,’ she laughs. ‘I’ve always wondered why he never seemed to lose weight even when I put him on a diet – now I know.’
It’s only thanks to a fascinating experiment – the results of which can be seen in Horizon: The Secret Life Of The Cat tonight on BBC Two - that Claude’s light-fingered ways have been revealed.
Dr Sarah Ellis, far right, shows the cat owners where their pets travelled during the one-week surveillance. Each cat's route was tracked and mapped onto a large screen at the BBC's Surrey Cat HQ
The programme documents how, for one week in April, 50 cats in the picturesque Surrey village of Shamley Green were put under 24-hour surveillance, fitted with a highly sensitive GPS collars and miniature ‘cat cams’ which recorded their every move.
The results will fascinate millions of cat owners – including, no doubt, George Osborne, whose tabby Freya was discovered by neighbours last year after disappearing for more than two years.
The absence, combined with her habit of wandering Whitehall’s corridors of power after she turned up again, has prompted some within the Government to warn that she could be working as a spy.
‘Before, we really didn’t know very much about what cats get up to,’ explains Dr John Bradshaw, an expert in human-animal interactions at Bristol University, who led the study alongside Sarah Ellis, a cat behaviourist at University of Lincoln’s Life Sciences department.
Each cat was fitted with a GPS collar so the researchers could track their movements. This map shows the data collected from three of the cats in the vilage. Claude's trek is shown in red, Deebee's is shown in blue, and Thomas' is the green lines
‘They’re fascinating creatures because they are part-wild and part-domesticated.’
They chose Shamley Green, he says, because of the high concentration of domestic moggies.
It didn’t take long to find 50 willing cat owners among the village’s 600 residents.
John says: ‘We put posters up in local shops and spoke to people in the street. Word spread. A month later we had a meeting in the village hall – almost every other cat owner in the village was there.
‘People were just very intrigued. They have this life with their cat but have no idea where it goes. All cat owners would like to find out what their pet gets up to.’
The tracking system which John and Sarah used was designed by experts at the Royal Veterinary College, based on technology used in Africa to track wild cats.
An interactive map created by the BBC lets you follow 10 of the 50 Shamley cats featured in the Horizon programme including Ginger, Sooty, Orlando, Hermie, Phoebe, Deebee Kato, Coco and Rosie. Each cat's path was mapped using GPS collars and is shown in a different colour
Each moggy was fitted with a specially-designed collar which collected GPS data on their location and level of activity.
The scientists could then remove the collars and plug them into a central computer installed at their temporary headquarters in Shamley Green’s village hall.
If the GPS system showed interesting movement patterns, the cat in question would be fitted with a ‘cat cam’ – a tiny surveillance camera designed by specialists at the BBC’s research and development centre – which dangled from their neck as they went about their business.
Claude’s night-time raids on his neighbouring cat’s food bowl, meanwhile, were captured with the help of a hidden camera erected in the corner of the kitchen, after his GPS data showed he was entering Rosie’s home.
Even cats that don’t like wearing collars can be trained to use them,’ says John. ‘And we didn’t have too much of a problem with the cameras – apart from a couple which got lost!’
It wasn’t long before John and Sarah were picking up all sorts of intriguing tit-bits.
First, the cats’ movement patterns: despite disappearing from their homes for hours at a time, very few of the moggies ventured further than 50 metres away.
Instead, they stuck to distinct, well-defined patches – Claude may not have been concerned about sneaking into a neighbour’s kitchen, but he rarely strayed more than five doors down the road.
Under surveillance: Dozens of cats were fitted with GPS collars and minature cameras which recorded their every move
The only exception was seven-year-old Sooty, who roamed two miles a day over an area of more than seven acres.
‘We had always been curious about what he got up to,’ says Sooty’s owner, 17-year-old A-level student Tom Townsend-Smith, who lives in Shamley Green with his parents and sister. ‘He disappears for long periods of time – now we know why.’
Unsurprisingly, Sooty descends from a line of farm cats, accustomed to roaming for miles around.
As for the others – though they may not have travelled far, they were remarkably proprietorial about their territory, marking it with distinctive-smelling chemicals which are secreted when they rub up against trees and rocks.
Not that they were averse to the odd bit of territorial invasion themselves. Even the most placid moggies, it turns out, can turn into feline Napoleons come nightfall.
Mischievous moggy: Janet Williams, 50, was surprised to learn that her mild-mannered cat Ginger was in fact embroiled in a Cold Turfwar with another cat down the road
Janet Williams, a 50-year-old book-keeper, was surprised to learn that her mild-mannered ten-year-old tomcat Ginger was moonlighting as the local trespasser after she had gone to bed.
‘We’d always thought he was quite a laid back cat. He might go next door or something, but no further than that.’
In fact, Ginger was making regular 4am trips into the garden of another cat, Tigger, further down the road – much to Tigger’s dismay.
CAT CAMS: THE SCIENCE BEHIND THE SURVEILLANCE
The research was carried out by Professor Alan Wilson and his team at the Royal Veterinary College, London who have been developing wildlife tracking tags and collars.
These collars feature high-accuracy GPS and electronic sensors that record the activity and movement of animals ranging from pigeons to big cats.
Wilson recently used the collars to study wild cheetahs in Botswana and were able to see when they are active and how far they range.
The team also discovered how often they hunt, how often they make a kill and new information about their athletic capabilities.
However, he added no-one has ever applied the same study methods to domestic cats.
The biggest challenge for the team was to make the tracking equipment - the GPS and activity sensor tags - small and light enough for domestic cats to wear around their necks on safety-release collars.
Describing his involvement in the study, Wilson said in a blog post: 'GPS uses a lot of power, but we could only use a small battery, so in order to save energy, we used an activity sensor to trigger the GPS only when the cat was moving.
'This also saved us from collecting a lot of uninteresting data on sleeping cats.'
Each of the collars also had a small radio transmitters fitted meaning the team could track the collar down if it fell off.
Once the smaller collars had been developed the research team set up Cat HQ in the Shamley Green Village Hall.
Wilson said that being on site enabled his team to examine the data as soon as it came off the collars, and to work closely with behaviour specialists Dr Sarah Ellis, of the University of Lincoln, and Dr John Bradshaw, of Bristol University.
For example, the collar data helped Wilson to decide where to place fixed cameras by identifying activity hotspots.
The data also told his team how active each cat was, which helped them choose which cats to fit with the 'cat cam' collars.
The team could also discuss the findings with the cats' owners.
Once Wilson processed the GPS and activity data for the cats his team used specially designed computer software to lay the cat tracks on top of aerial photographs from Ordance Survey.
Since the programme was filmed, Wilson said he has have collected more data from the village cats and the results will be published in a scientific paper.
VICTORIA WOOLLASTON
The two cats’ ‘cat cams’ show them squaring up to one another, their blurry forms illuminated by the cameras’ in-built infrared torch. Circling one another in a kind of feline Cold War, neither moggy wants to make the first move to attack.
Instead, after much hissing, Tigger retreats.
Says John: ‘We saw stand-offs but not very much fighting at all.’
So if they’re not scrapping – how exactly do the cats go about protecting their territory?
The answer is with the help of a sophisticated shift system. Though the GPS data showed that the paths of Shamley Green’s felines did, at times, overlap, it also demonstrated how each individual moggy avoided getting into unwanted confrontations by venturing out only within strictly-defined time windows.
Cat routines: Kato, pictured in 'his' garden wearing a cat cam, would only leave house when the neighbour's cat had vacated the streets
50-year-old courier Debbie Harris, who has lived in Shamley Green for more than a decade, has long wondered why her nine-year-old black-and-white tom Kato only ever seemed to leave the house just as Debbie was going to bed.
It wasn’t until his roving patterns – which saw him patrol half a mile around Debbie’s house every night at the strike of 10pm – were compared with that of a neighbour’s cat, a six-year-old Tortoiseshell named Phoebe, that she discovered the answer.
While Kato ventured out in the street after dark, Phoebe stuck to daytimes, beginning her daily perambulations at 1pm on the dot – all the while under Kato’s watchful (and wary) eye.‘I’ve seen him sitting on the windowsill eyeing up Phoebe from afar, says Debbie. ‘I was quite amazed when I found out that they deliberately avoid one another. I wasn’t expecting it at all. It’s very clever of them.’
Watching: The 50 cats in Shamley Green were put under 24-hour surveillance shedding new light on the hidden lives of cats such as Paulina Bayliss' moggy Toby
Deebee is shown wearing her cat cam, being held by owner Julia Helby. Deebee is one of the newest cats in the village
The pair’s uneasy truce was a pattern repeated across the village where cats were living side by side.
John says: ‘Our GPS data points towards the other cats doing the same. The key to understanding cats is understanding their territory and their relationships. They are quite solitary really, so when you cram them together in a village, they don’t like each other very much. They are descended from territorial animals – it’s their wild legacy. We aren’t sure how the system develops but we think it’s from their routine of marking their territory with their scent.’
Scientists believe that, as well as being able to smell where other cats have been, they are able to tell how long ago there were there. In one cat had been in the vicinity recently, the other is likely to steer clear until more time has passed. Once the routine has developed, it becomes a matter of habit.
Another revelation was that, even when they were out and about, the cats of Shamley Green rarely went hunting for themselves. Over the course of the week, the cat owners were asked to bring in every bit of prey their pets brought home.
Aside from the odd vole or shrew, there wasn’t very much to speak of. Just 20‘kills’ by all 50 cats. Which may go some way in explaining Claude’s cheeky habit of pilfering his neighbour’s nibbles.
In his defence, Claude was far from the only light-fingered feline in the village.
Investigative team: Dr John Bradshaw, Dr Sarah Ellis and Professor Alan Wilson discover what cats are up to behind their owners' backs
During their week of surveillance, several others were caught sneaking into kitchens that weren’t their own for a late-night snack.
Tom Townsend-Smith was amused to hear that Sooty regularly sneaks next door for an evening bite: ‘It’s very cheeky of him – it’s like he has a second home.’
And Janet Williams was finally given an explanation for Ginger’s lack of appetite at home, when she found out that he had been filching titbits from the feeding bowl of an elderly female cat down the road: ‘She obviously had nicer food than we give him. It’s quite cowardly of him - picking on an old girl like that!’
So, next time your feline friend slips out through the catflap, give a thought to what he might be getting up to when your back’s turned. Burglary, territorial invasions, and carefully timetabled patrols – it’s all in a day’s work for the Machiavellian moggy.