PICA: EATING THE INEDIBLE
Copyright 2008, S Hartwell
Pica means eating non-food items. The behaviour ranges from sucking, chewing and biting through to swallowing bites of items. Pica (from the Latin for "magpie"). It should not be confused with the suckling/nursing behaviour that some cats retain into adulthood. Commonly consumed target items include wool, string, elastic bands, electrical cords, tissues, tinsel and houseplants. Other objects have included cassette tape and the rubber "teat" section of a child's dummy (pacifier). Eating a little grass or herbs is normal cat behaviour; indoor cats may eat houseplants if there is no grass accessible.
Like many obsessive or abnormal behaviours, the cat persists in doing it because the it is comforting or rewarding. The reward might be a nice taste, a full stomach or simply getting attention from the owner. The challenge is to make the behaviour unrewarding and redirect the behaviour into something rewarding for the cat and acceptable to the owner. Sometimes it is a displacement activity where an abnormal activity is substituted for normal behaviour because the cat can't express the more normal behaviour i.e. the normal behaviour is being thwarted.
PICA, WOOL-SUCKING OR PREY-PLUCKING?
Wool-sucking (or fabric-sucking) is a misdirected form of nursing. It's similar to a child's thumb-sucking in providing comfort.. Though sometimes mistaken for wool-eating, the item (sweater, blanket etc) is only sucked, not chewed, bitten or swallowed. Other commonly suckled objects include the cat's own tail, other cats or pet dogs. Behavioural treatment may be needed to build up the cat's confidence so it no longer resorts to "comfort nursing".
In general, the younger a kitten is when it is weaned, the stronger the urge to nurse and the more persistent the comfort-nursing. Usually it decreases naturally as the kitten grows up, but it may persist or resurface in early-weaned or hand-reared cats, particularly at times of stress. More rarely it becomes a compulsive behaviour or progresses to pica.
Some owners provide an old sweater for the cat to suckle on while protecting other garments by storing them away from the cat or dabbing hot chilli sauce onto them.
Plucking the target resembles pica but is a misdirected prey-related activity. The cat holds down the (often woollen) blanket or garment with its paws and uses its teeth to pluck or tear at it. This is the same behaviour found when a cat plucks or tears fur, feather or flesh from larger prey items (e.g. pigeons). The clothing/blanket isn't swallowed anything the cats tears off is discarded. One of my cats, Sappho, exhibited this behaviour towards crochet blankets.
In the case of one Siamese cat, it took a sock to its eating area and plucked at it periodically during the meal (canned food). The owner attributed this to "teeth cleaning" but it was probably misdirected prey-plucking/tearing behaviour as it only occurred at mealtimes.
Anecdotally and in studies, Siamese cats seem most prone to pica, especially with woollen items. There are reports of Burmese cats being attracted to electrical cables (possibly attracted to plastics). This indicates a genetic predisposition.
In one British study of 152 fabric-eating cats, 55% were Siamese, 28 % were Burmese, 6% were "other Oriental" and 11% were other breeds or randombred cats. Pica also ran in families with over half the owners reporting that their cats' siblings also ate wool or fabric. 93% started with wool and moved on to other fabrics. 64% also ate cotton. 54% ate synthetic fabrics. The wool-eating typically began between the ages of 2 and 8 months (a time period encompassing weaning and puberty) and there was no gender bias. In some cases, the habit was so established that owners had no choice but to provide an old garment for the cat to chew.
In the “He’s Eating Me Out of House and Home” survey (published June 1991, Cat World magazine), Neville noted that wool-eating has been recorded in Siamese cats since the 1950s. This study showed Siamese and Burmese were more likely to exhibit pica than other breeds/randombreds. A summary of results is given at the end of this article. In recent years, it has been suggested that leaving Siamese/Oriental kittens with their mothers until 16 weeks old reduces the predisposition to pica. While not yet proven, it is certainly worth trying.
IS PICA DANGEROUS?
Most owners notice pica because it's destructive to household items. It is also a health hazard to the cat. Chewed or ingested non-food objects may be poisonous. Ingested non-food items can cause life-threatening intestinal blockage. Swallowed lengths of string, tinsel or cassette tape can cause intestinal damage as it gets caught in the loops of intestine. Swallowed thread may have a needle attached. Some objects are intrinsically dangerous to chew on – electrical cords carry the risk of electrocution.
Clay-based cat litter contains bentonite which can cause intestinal blockages. Cats that eat cat litter may have mineral or vitamin deficiencies. Switching to wood-based , paper-based or wheat-based litter may resolve the pica, or at least provide a safer item to swallow.
Pica can be fatal to cats. Berenice, a British animal care counsellor at the SPCA in Singapore experienced fatal pica with her black oriental-type stray, Magic. She adopted Magic at 4 months old. His pica worsened as he grew older – matches, plastic and items he robbed from neighbours’ apartments such as a feather boa. Berenice was unable to stop the abnormal eating pattern and her vet, a European in Singapore, assumed magic was hungry (rather than it being a behavioural problem) and advised her to feed Magic lots of pumpkin to fill him up. Unfortunately Magic managed to raid a dustbin, despite all attempts to keep him away from inedible objects and died a quick, painful death aged less than 2 years old. Berenice has since come across advice that Siamese and Oriental kittens should not be removed from the mother before 16 weeks old as this reduces the predisposition to pica.
WHAT CAUSES PICA?
The cause(s) vary from cat to cat. Sometimes there is no easily identifiable cause. Siamese and Burmese appear to have a genetic predisposition to pica. It can also be a learned behaviour e.g. kittens may learn to eat unusual objects from a mother with pica.
Abnormal cholecystokinin (CCK) metabolism is a suspected cause in some cats. Hyperthyroidism causes increased appetite and may lead a cat to eat non-food items; one hyperthyroid stray was observed eating dirt (this stopped when the hyperthyroid was resolved). Pica has also been linked to Feline Leukaemia Virus (FeLV) and Feline Immunodeficiency Virus (FIV/FAIDS). It has also been linked to anaemia caused by immune system disorders (rather than from dietary deficiencies) and pancreatic disease. Neurological disorders may cause pica and/or other obsessive behaviours. Any cat that suddenly starts eating unusual things should be checked over by a vet to rule out physical illness as a cause.
Some cats simply enjoy biting chunks out of objects, probably because it is akin to biting through the skin and gristle of prey. This can include biting table legs, plastic objects or car tyres (one of my cats, Affy, liked to bite warm car tyres, but didn't swallow the rubber). Clay cat litter is another commonly eaten non-food item.
Sometimes a cat will eat its own faeces (coprophagia); this is sometimes a misdirected mothering instinct as nursing queens will eat their kittens' stools until the kitten gains full control of its bowel. Predators, including cats and dogs, sometimes eat the stools of other animals, usually of prey species. They may get additional nutrients from the prey's incompletely digested food..
While cats naturally eat small amounts of grass, consumption of large amounts of plant matter indicates illness of dietary deficiency or illness. Indoor cats may eat houseplants either through boredom or because there's no grass available; the question then becomes "how much plant matter is the cat eating?"
Bored cats, particularly indoor cats, are more likely to develop pica than outdoor cats. Attention-seeking cats may use pica as a way to get the owner to interact with them. It may be learned from the mother or other cats in the household. Sometimes the object has an attractive smell or taste. And sometimes, it is purely and simply hunger - maybe the food in the food bowl is stale or the cat doesn't like the flavour or it's all gone and the cat is still hungry!
First rule out or treat medical causes. Hyperthyroidism can lead cats to eat cat litter, dirt, stale food and non-food items. It can be treated through medication, surgery or radiation treatment (these treatments depend on availability, cost and the cat's physical condition) and the cat's appetite will diminish once the thyroid hormone levels reduce. This normally resolves the pica.
As far as practical, put the target items out of the cat's reach. This may mean moving plants to high shelves, making cables inaccessible to the cat (e.g. under the carpet or through ducting), keeping clothing/bedclothes in the wardrobe, drawers, storage crates or airing cupboard and not leaving laundry lying about. It is more difficult if the cat chews bedclothes while they are on the bed unless the bedroom becomes out of bounds. If it isn't possible to exclude the cat from the target items it might be possible to find a safer alternative for the cat to chew on.
Alternative chewing items (for cats that don't swallow the non-food item) include durable cat toys (or the smaller "Kong" dog toys), food-dispensing cat toys, rawhide chews, dried pig's ear chews etc. Letting the cat chew on a large raw beef bone once a week may appease its need to chew. Some vets recommend raw chicken wings. The chewing action also keeps the teeth clean and exercises the jaw muscles. A pot of grass may be sufficient to distract a cat from houseplants; this can either be dug up from the lawn or grown from seed.
If the target is specifically soil the cat may be attracted to the texture (mouth feel). Adding bran, vegetables or crunchy items may help reduce the pica. A high-fibre, challenging diet containing gristly meat may help satisfy the instincts to chew and keep the cat's belly full for longer.
Another less palatable suggestion for many owners, is to provide the cat with dead day old chicks or dead whole rats and mice (available from pet shops that cater for reptile or bird of prey owners). These satisfy the thwarted instincts to tackle food in its natural form as well as providing a more interesting texture than commercial pet food. Some farm shops and butchers can supply hens (usually birds that have ceased laying) or rabbits (farmed, not shot rabbits - the latter contain gun pellets!) with feather or fur on them. This means feeding the cat somewhere that is easy to clean up the blood. Though messy, this might succeed with hard-core or life-endangering pica cases and is especially suited for indoor-only cats with no access to prey. As with all raw meats there is a small risk of salmonella making this unsuitable for cats with poor immune systems.
Interactive play sessions (15-20 minutes) can reduce boredom and may also reduce attention-seeking pica. Prevent boredom during your absence by providing a stimulating environment with climbing posts and toys (including food-dispensing toys). Hiding small biscuit treats around the house or inside puzzle feeders provides stimulation.
Bored cats often eat more, not through hunger but as something interesting to do. Higher fibre in food allows them to eat more without consuming more calories and may prevent snacking on objects by making food available more often. The trend of feeding a cat a cupful of calorie–dense dried food (kibble) may provide adequate nutrition, but doesn't fill the stomach - cats' bodies are used to bulkier flesh-and-bone diets. If the pica is due to the cat wanting to feel full then high fibre, low calorie food will do this. A timed feeder dispensing small amounts of food at frequent intervals may also distract the cat from eating non-food items.
If you can't make some targeted items inaccessible, make them unattractive. There are a number of non-toxic bitter substances available in pet stores for just this purpose. Alternatively, hot chilli sauce or cologne can be used and many owners find this effective in deterring cable-chewers. Make sure the deterrent is specifically non-toxic to cats as some cats will ignore the bad tastes, driven by their strong urge to consume the target item. If the cat responds to catnip, treating some of its toys with catnip at the same time may help redirect its pica into play behaviour.
If it is impossible to restrict access to the target and the pica may cause harm (e.g. electrical cables), the cat may need to be penned (with food, water, litter tray and toys) when it can't be directly supervised. Monitor at other times and distract it from the pica object if it starts to show interest. Don't simply punish it for showing interest, provide an alternative non-food activity e.g. thrown scrunched ball of paper.
TACKLE THE CAUSE, NOT JUST THE SYMPTOMS
Some sites recommend using strong smelling air-fresheners or pot pourri to deter the cat from going near the target object, but these items are toxic to cats and should not be placed within the cat's reach – these would be a case of killing the patient instead of curing him. There have been cat deaths reported in relation to both pot pourri and the contents of plug-in air fresheners.
Remote punishment using a water pistol tackles the symptoms not the cause. The cat will probably transfer the pica to a different object or location. Never use this form of punishment unless you also provide an alternative outlet for the problem behaviour.
Unfortunately, in some cases it is possible to stop the cat chewing one object only to discover it has found a new target for its pica. If the cat tends to be anxious, the chewing may be stress-relief, try to identify and reduce the stresses and provide it with a safe undisturbed area it can retreat to.
If none of the above work, a behavioural modification plan worked out by a Pet Behaviourist is required. As a last resort, medication may be prescribed, but these tend to be sedatives or anti-anxiety medications and do not treat the cause of the problem, only the symptoms.
WOOL CHEWING AND LANOLIN
Where the target of the pica is specifically wool (a common target in Siamese cats) some owners have stopped the wool-eating by adding lanolin (an oil removed from the fleece before it is spun into yarn) to the cat's food. It isn't yet known why the cats specifically craved lanolin.
PHOTOGRAPH LICKING AND PLASTIC BAG EATING
Plastic bags and photographs (from photographic labs rather than home-printed digital photos) are common targets for licking. Often this doesn't progress further than licking, but some cats have needed surgery to remove parts of plastic bags from their stomach or intestine (the symptoms being poor appetite and vomiting). These can be hard to locate as they don't show up on x-rays.
It isn't known for certain why cats find plastic bags attractive to lick. It's possible they like the texture (tongue-feel) or even the sound made while licking. A more likely reason is they like the taste. Some plastic used in shopping bags are made from rendered animal fats, fish oils, gelatine or petroleum jelly and cats are attracted to the residual odour of these. Possibly the bag has been used to carry a food item and the cat is attracted to the residual scent on the plastic.
Gelatin may be used in photographic emulsion which is probably why some cats like licking commercially processed photos. Cats perceive odours differently to humans which may explain their attraction to certain chemicals in plastic and in photos.
Rubber is also attractive to some cats. My cat chewed car tyres. Many pica-prone cats have an appetite for rubber bands or babies' dummies. Peter Neville reported a cat that specialised in consuming condoms. This reached a painful climax, and a request for treatment, when the cat tried to consume a condom just after its owner had donned the item.
Treatment with drugs is more widely accepted in the USA than in the UK. This reflects the different lifestyle imposed upon cats. An indoor-only lifestyle is stressful to a territorial predator compared to an indoor-outdoor lifestyle. Stressed animals may develop abnormal, obsessive or stereotyped behaviour to cope with confinement. These behaviours, though they may seem bizarre or even self-harming, provide comfort to a stressed animal. Pica may result from stress or anxiety.
Drugs should only be used in conjunction with behavioural modification, stress reduction and making the target unavailable/unattractive. Simply sedating a cat is not the answer – you should find out and tackle the cause of the problem, not just the symptoms. Commonly used drugs are Diazepam (Valium), Amitriptyline (Elavil), Clomipramine (Anafranil, Clomicalm), Buspirone (BuSpar), Fluoxetine (Prozac), Paroxetine (Paxil), Clorazepate (Tranxene) and Alprazolam (Xanax) (brandnames will vary according to manufacturer and country). These are not suitable for all cats due to age and liver/kidney/heart conditions. As with humans, some cats suffer side effects from certain drugs.
A Feliway (feline facial pheromone) plug-in diffuser is also used to alleviate anxiety and may reduce anxiety-related pica. The antihistamine Piriton has also been used as an anti-anxiety/sedative in cats.
UK PICA SURVEY 1990
Peter Neville published “He’s Eating Me Out of House and Home” in Cat World, June 1991, pg 16-17. The survey was conducted during 1990 with the help of John Bradshaw, Animal behaviour unit, Southampton University. 152 owners of pica-afflicted cats were surveyed. Of the cats surveyed, 55% were Siamese, 28% Burmese, 11% mixed and 6% “other Oriental”. Of the owners who had knowledge of their cat's siblings, 58% had a brother or sister that also ate fabric, indicating a genetic predisposition. There was a 50:50 split between male and female. In only 15% of cases, the pica vanished after neutering. Some cats exhibited pica periodically while others had it constantly.
93% ate wool; Siamese accounted for about half this number followed by Burmese, mixed breed and “other Oriental” 64% ate cotton; with the proportions being similar to above 53% ate synthetic fabrics, again with similar breed breakdown 20% ate non-fabric items (electric cable, rubber bands, wallpaper, rubber dummies (pacifiers); Siamese and Burmese were roughly equal, followed by other Oriental then mixed breed. 8% ate paper or cardboard; Burmese outnumbered Siamese in this respect.
Two thirds of the cat surveyed first exhibited pica between the ages of 2 and 8 months, a period covering both weaning and puberty. Notably, a “significant number” exhibited pica within 1 month of being acquired, indicating that the move of home was a trigger rather than age. Two-thirds of the cats also showed infantile behaviour such as kneading and dribbling; those adopted at a younger age continued this behaviour for longer than cats acquired when older. Cats with periodic pica had a trigger factor such as introduction of another cat, medication, moving home or separation from the owner. One cat had been rehomed 4 times due to pica (each rehoming may have triggered its pica).
Having cut their teeth, so to speak, on wool, many cats expanded their tastes to include cotton towelling and synthetic fabrics. In some cases the articles were sucked; these were still tabulated even though it was comfort nursing, not true pica. Some cats had specialist tastes such as hand-knitted garments or wet socks. One cat required 3 surgical operations to remove babies’ dummies (pacifiers) from its gut; the owner was unable to locate the source of the dummies as they had been consumed while the cat was outside of the house.
Some cats retrieved items from washing lines or laundry bins in order to chew them. Another chewed the arm of an armchair down to the foam in a single afternoon. One had single-handedly destroyed a £1000 three-piece suite. The average cost of the destruction caused by pica was £136 (it was not stated whether this included the cost of surgery where gut blockages ensued).
Ambush punishment with a water pistol was generally ineffective in stopping the behaviour; the cats simply became more secretive. The use of pepper or chilli on target fabrics resulted in cats developing “more exotic” tastes. Eucalyptus oil or menthol was more effective. Some cats stopped eating fabric whenever food was offered, others merely took alternating bites of food and fabric.