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The Indoor Outdoor Debate – Part 2

| December 27, 2011

The Indoor Outdoor Debate

There are Hazards on Both Sides of the Door!

Outdoor hazards are obvious such as: volume of traffic, incidence of disease, a cat’s ability to protect itself (deaf, partially sighted, frail), its danger to other cats (if it has a transmissible disease), predation upon vulnerable wildlife, any danger to humans (a British cat, Gizmo the postman hater, had to be confined for the safety of postmen and other delivery men), danger from humans (e.g. gamekeepers), spilt car antifreeze and garden chemicals. In some area, cat legislation/licensing dictates an indoor-only lifestyle.

A correspondent wrote:

“Since I have lived in National and State parks for many years I have to keep my cat indoors. Not only does the NPS have regulations prohibiting any pets from running loose, living in parks usually means I’m living near a lot of wildlife! My cats have always adapted well, although when they are younger they tend to be a little more anxious to venture outside.”

Another wrote:

“I used to have indoor-outdoor cats because I lived in an area where there was little traffic. I stopped when a neighbor’s dog attacked my girl and brain-damaged her so badly that she had to be put down.”

These are valid reasons for keeping cats indoors and show that, in some areas, indoors is safer. It is dangerous, therefore, to condemn other people for keeping cats indoors (or allowing them outdoors) on the basis of your own local conditions and experiences – you don’t know what their circumstances and experiences are.

Indoor hazards may be less obvious but they do exist, for example: household chemicals, human medications, eating dangerous objects (elastic bands, needle-and-thread), pull-string blinds, electrical wires, crush injuries from toppled items such as stepladders, caught in slammed doors. Sure, an owner can be sensible about safety, but human safety watchdogs say that most accidents happen in the home.

Cats sharing their homes with smokers are twice as likely than other cats in non-smoking households to develop Feline Leukaemia, the risk rises to three times more likely in cats exposed to smoke for 5 years. Indoor-only cats are at increased risk because they cannot spend time outdoors away from the smoke (Study 1993-2000, Tufts University, Grafton, Massachusetts, USA; led by veterinary oncologist Anthony Moore). Incense smoke, burned to scent the house, may be carcinogenic in the same way as cigar/cigarette/pipe smoke.

Moore and his colleagues studied 180 cats treated at a Tufts veterinary hospital between 1993 and 2000. They found that cats exposed to second-hand smoke were more than twice as likely to get the disease than those living with non-smokers. Cats living with two smokers had four times the risk. They also swallow carcinogenic dust, soot and ash when they groom themselves.

Indoor Cats Need Stimulation

Can a link be established between indoors only lifestyle and behavioural problems? Quite possibly, according to British behaviourists. British behaviourists report more problems in indoor cats than in outdoor cats. There are proportionally more pet shrinks in the US than in Britain; this corresponds largely to the different styles of cat keeping as cats display ‘displacement’ behaviour when their natural behaviour is thwarted. This does not apply to sexual behaviour since neutering removes the reproductive urge rather than thwarting the desire.

Indoor-only is the predominating lifestyle in the USA and behavioural problems are cited as major factors cats being relinquished to shelters or euthanized. Is the higher number of behavioural problems in indoor cats due to their owners being able to witness a problem behaviour? An owner cannot see a cat having a temper tantrum behind the garden shed! It is true to say that cats with access to outdoors can more easily and more fully express natural instincts, burn off energy and vent any aggression (albeit on other cats or on prey).

It is also true that not every indoor cat will suffer from “indoor stress” (see later) and behaviour problems. It depends on the cat’s personality (which may be related to breed), activity level, age and health. Behaviourists have noted that indoor cats can become neurotic or bored if a stimulating 3-D environment is not provided by the owner. They also need more regular play since an indoor environment doesn’t present the ever-changing environment found in a garden.

Some natural behaviours can turn into obsessive behaviours in a stressed cat. The stress may be due to the indoor-only lifestyle not suiting the individual cat. The behaviour may initially have been an outlet to release energy or tension; the reward of “de-stressing” leads the cat to repeat the behaviour more and more often. Eventually it ceases to act as stress release and other aberrant or compulsive behaviours begin. The behaviours tend to be carryovers from kittenhood (sucking on things), exaggerated territorial/hunting behaviour (spraying, ankle-grabbing) and over-attachment/separation anxiety. Books on behaviour problems (some commenting on the link to lifestyle) have been written by biologist/naturalist Roger Tabor (Bristol, UK), Nicholas Dodman (Tufts, USA), Peter Neville (Association of Pet Behavioural Counsellors, UK), Claire Bessant (Feline Advisory Bureau).

Some owners of indoor cats are resorting to calming drugs to control behavioural problems. Other owners consider this equivalent to sedating patients and prisoners who go “stir-crazy” through confinement. Long-term drug therapy is probably not good for cats (this phenomenon is too new for any long-term studies) and a change in lifestyle or environmental enrichment should be considered as alternatives.

Other owners have equipped their homes with high-level walkways, cat trees and they vary the available toys. This keeps cats stimulated, encourages exercise, provides “safe” places (where a cat can retreat if it wishes) and appears to reduce, or even prevent, a number of behavioural problems. It is exactly the same idea as environmental enrichment in forward-thinking zoos.

Pussy on Prozac?

Modern life is stressful for pet cats according to animal behaviourists, particularly for cats kept in an environment where they cannot easily express their natural behaviours. Some develop neuroses that cause violent, obsessive, destructive or self-destructive behaviour. In the USA, behavioural problems are a major reason for taking a pet cat to a shelter or having it euthanized. Destructive behaviour means that many cats are declawed. Anti-depressants and behaviour modification (including scratching post training) are alternatives. Alan Parker, a vet specialising in neurology at the University of Illinois at Urbana-Champaign, Illinoise, USA explained that cats key their emotions off their owners. If the owners are agitated, the cat becomes agitated. By the 1990s, life for humans had become far more stressful, US cats were more often cooped up indoors and they also became stressed.

One aberrant behaviour triggered by stress is Feline Hyperaesthesia Syndrome (FHS) which causes cats to perform repetitive, often violent or self-destructive behaviour, including over-grooming. Affected cats have been know to lick or chew away their fur, obsessively bite their own flanks or tails, or repeatedly attack the owner. In some cases, cats have damaged their tails so severely that amputation was needed. FHS seems to be normal behaviour repeated to an abnormal (excessive) degree. The cat becomes fixated on a particular activity. Like animals pacing or swaying in barren zoo cages, the behaviour provides an outlet and becomes a reward in itself. Most reports of FHS come from the USA. Reports from the UK are rare, probably because the majority of cats are free to go outdoors where the environment is more stimulating.

FHS can be treated with valium, although this powerful drug can turn affected cats into feline zombies. Now, Parker and others are experimenting with other psychoactive drugs such as clonazepam, imipramine and megestrol acetate, all of which modify behaviour by blocking specific neurotransmitters in the brain rather than tranquilizing the cat.

Behaviourists also recommend training, more interaction with the cat or simply more affection to break problem behaviour patterns. Enriching an indoor environment is important for indoor-only cats in the same way that enriching the caged environment is important for zoo animals. Owners tend to forget that cats live in a 3D world and naturally walk along branches, tops of walls etc. They do not live purely at floor level so climbing frames or cat trees with platforms/vantage points at different heights are essential for indoor cats. If the cat can be leash trained or have access to an outdoor pen, this also provides stimulation.

Raising Indoor Cats, Supervised Outings

A cat which is raised from a kitten as an indoor-only cat accepts its confinement better than an indoor-outdoor cat (or previously outdoor-only cat) which finds itself suddenly under house arrest.

“For acclimation, I try to pick the day with the absolute worst weather you can imagine (deep snow, thunderstorms, etc.) and just set the babies (after their first shots, of course) down outside the door. I leave the door open and they are usually back in the house in a shot. And they rarely show any interest in going back out. Of course, they watch the world go by through the window, but if the door is opened, they are in another room – immediately!”

Some owners take their cats on supervised outings which the cats enjoy.

“We take our cats out on leashes into the city fairly regularly. We often take them on the subway to the downtown Boston Quincy Market area (they love to go fish shopping at the Haymarket stalls) or by car to the arboretum or the harbor scene. We have only once seen anybody else with another cat on a leash in all the years we have been doing this. People are missing a wonderful experience.”

“We found out immediately that the cats would NOT associate the house doors with getting outside if we CONSISTENTLY took them out in carriers. Now they have the idea of a carrier as a means of going out to fun experiences. They will jump right into the carriers — but have never gone outside through a door.”

There are those who argue that any access to outdoors, whether on a leash or in an enclosure, is irresponsible as it exposes cats to risk of infection. Others view this as owner paranoia. It is up to each owner to determine what risks are acceptable. A cat has no concept of its own longevity; it doesn’t plan for the future as do humans. Some owners decide that the cat is happier and has a more enriched life with some degree of outdoor access. Others wish to protect their cats from all perceived hazards at all costs. Each must choose the lifestyle appropriate to their cat’s enjoyment and their local circumstances. Moreover, each must respect the views of the other even if their do not share those views.

An indoor-only lifestyle, unless carefully managed and with an enriched environment affects feline health in other ways. Frustrated cats become stressed and anxious. Bored cats may over-eat and become overweight with a tendency to diabetes, heart disease and other weight-associated medical conditions.

Indoor Stress”

According to Tufts (Catnip Newsletter, October 1995) “stress” is the “term used by veterinarians to describe the mental and physiological changes that occur in an animal when it perceives something potentially threatening”. A perceived threat causes various physiological responses which were once essential to survival as the fight/flight/feed/breed response. Adrenaline is released to prime the body for one of these four survival responses.

The threat triggers activity in the animal’s autonomic nervous system, the portion of the nervous system which controls involuntary body functions such as heart rate, blood distribution and respiration. The pupils of the eyes dilate to admit as much visual information as possible. Tiny muscles in the skin around the hair follicles contract, causing the fur to stand erect and make the threatened animal look bigger and more intimidating. Mood changes accompany physiological changes. The threatened animal may become hyper-alert which leads to aggression towards anyone who approaches too near – in other words the cat is in a highly excited, reactive state. Once the challenge has been met with the appropriate fight/flight/feed/breed response, the body reverts to its normal unstressed state.

In the wild, these changes are life-saving – there is an identifiable source of fear to be dealt with. An indoor-only cat rarely needs the protective benefits of this physiological reaction. To begin with, an indoor cat may be unable to recognise or identify the source of its fear (noises from next door, a dog barking outside) or it may be unable to avoid a recurring source of fear (an aggressive companion cat, a badly behaved child). Fear then leads to anxiety which can become chronic; The cat may be in a continual state of anxiety or may have recurring “anxiety attacks” in response to trivial things such as dropped car keys.

An indoor-only cat is trapped with its stress factors. It can’t flee and there is nothing for it to confront (feed and breed are also not appropriate responses). Somehow it needs to reduce its stress. One way of doing so is to act out a response – to attack its owner or to flee and hide under the bed. Other behaviours get co-opted into the repertoire as ways of relieving stress and anxiety – refuge in kittenish behaviour, destructive behaviour towards objects – known as displacement behaviour.

Chronic stress or anxiety leads to health problems. In biological terms, the stress response is only intended to be a short-term state enabling the cat to defend itself, flee, take advantage of a food source or take advantage of a mate (in situations where it might not meet a mate again for some time). It primes the body for immediate action. The body is not intended to remain in this primed state for long periods of time. One indication of stress is high concentrations of the corticosteroids (adrenal gland hormones e.g. cortisol) in the blood/urine. Cortisol lowers the immune response, one reason stressed-out humans can’t shake colds as easily as non-stressed humans. If large amounts of the hormones persist due to chronic stress, the result can be chronic or recurrent illness or even death (laboratory rats have literally been stressed to death to demonstrate this).


This is an appendix to The Indoor Outdoor Debate. Most outdoor hazards are obvious, but indoor hazards may be less so. It applies to all cats, but cats which spend most of their time indoors have more opportunities to get into mischief!


  • Check for cats before shutting doors, they risk injury if caught in a slammed door.

  • Some cats chew on rubber or plastic; electrical leads (TV, hi-fi etc) should be hidden or coated with anti-bite preparations.

  • Deter/prevent cats from scaling Venetian Blinds; cats have been strangled by getting caught between the slats.

  • Your favourite essential oils may be toxic to cats; extinguish oil burners/vaporisers and scented candles when you leave the room

  • In the festive season: many evergreens are poisonous, fairy lights should be unplugged if the tree is unattended, the tree should be firmly anchored (or attached to ceiling hooks so it can’t topple), baubles should be unbreakable, tiny tree-decorations should be avoided as they can be swallowed.


  • Close doors of fridge, oven, dishwasher, washing machine and tumbler dryer

  • Store knives and cooking utensils away from cats

  • Dispose of food scraps, bones, cans, bottles and cellophane wrap in kitchen rubbish bin

  • Close the kitchen rubbish bin securely or keep it in a cupboard fitted with safety catches – or use an outside bin only

  • Keep detergents, bleaches, household cleaning supplies and medicines in closed cupboards; some cats get a ‘high’ from bleaches

  • Don’t allow cats to jump, walk or sit on ceramic hobs even if cool, one day they will probably get burned paws.

  • Store the iron out of reach, make sure the ironing board and any stepladders are secured against the wall or stored in cupboards


  • Put small, easily swallowed objects in drawers, don’t leave them on the floor

  • Make sure electrical leads are not frayed and are inaccessible to cats

  • Secure a fireguard in front of the fireplace – if the fireplace is purely ornamental, block the bottom of the chimney with newspaper as cats can get stuck up chimneys

  • Put plants out of reach of cats unless they are known to be non-poisonous to cats

  • Put breakable ornaments out of reach or in closed display cabinets.


  • Keep make-up and make-up removers in shut drawers

  • Keep any bedside medical supplies in a drawer.

  • Store swallowable items such as hair-grips, hair-pins etc in a drawer or cabinet.


  • Keep shampoos, toilet cleaners etc in stoppered bottles and put them out of reach

  • Keep the toilet lid closed. Curious kittens have fallen into the loo and drowned as the sides are too slippery for them to climb out.

  • Don’t leave full or filling baths unattended, an unwary kitten may fall in and not be able to get out.

  • Make sure glass shelves and mirrors can’t be dislodged by exploring cats.

  • Keep medical preparations in a cat-proof bathroom cabinet.

Copyright & Credit: Sarah Hartwell – MESSYBEAST.COM
Photo copyright and courtesy:
Consuelo Pizarro

Category: Feline Articles, Feline Health and Care, Feline Resources

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