It’s become quite well known that the family of Oriental cat breeds which includes the Siamese, Javanese and Oriental shorthair and longhair (and other breeds), are susceptible to developing eating non-nutritious substances, which is called pica, and in particular fabric. The big question is what causes it. And the small answer is that the experts are not completely sure. There are quite a lot of theories including early weaning and the presence of lanolin in wool. The early weaning element may certainly be a factor and the presence of lanolin reminds the cat of their kittenhood when being nursed at their mother’s breast. However, Dr. John Bradshaw tells us that he has tested the lanolin theory and found that it did not hold up.
It should be said also that eating and sucking non-nutritious substances is not confined to pedigree cats or cats in the Siamese cat family because you will see it, too, in non-purebred cats. I fostered a cat who did not eat wool or a fabric but he liked to suck my wrist. He was a random bred tabby cat.
Apparently, the fabric of choice for Oriental cats is wool followed by cotton. Synthetic fabrics such as polyester and nylon are less popular. Dr. Bradshaw reports that most of these cats start by chewing woollen items and many progress to swallowing chunks of fabric which they’ve chewed off, or they might move onto other materials.
It appears that the cats are confusing fabrics with food. He reports that he observed a Siamese cat dragging an old sock up to his food bowl and taking a mouthful from the sock and a mouthful from his food bowl. He believes that it is unclear as to why they prefer wool over other fabrics and, as mentioned above, the lanolin theory, which would have explained this does not stand up.
He writes that wool eating is restricted to a small number of closely related cat breeds so on this basis it would appear to have a inherited. However, he writes it does not seem to be inherited directly. He ran a survey of 75 kittens produced by seven mothers. Three of the mothers were fabric eaters and four were not. Thirty of the kittens had become fabric eaters but to complicate matters many of these had normal mothers.
He couldn’t explain why a third of the kittens had become fabric eaters because he couldn’t relate that behaviour to genetic factors nor an imitation of their mother’s behaviour.
However, he found that many of the cats that ate fabrics also had other abnormal behavioural traits such as biting their owners and excessive scratching. This is often a sign of stress. As a consequence, he believes that fabric eating may be “soothing oral behaviour” which is employed to reduce stress. It is rather like thumb sucking in human infants. Kittens also suck thumbs incidentally (for the same reasons?).
He believes that this is supported by the fact that fabric eating often starts among Oriental cats within a few weeks of the cat being rehomed when he or she may be stressed by the change in their environment.
And onset may also occur at around one year of age, even within a stable home, which is the time at which they become sexually mature and start to come into conflict with other cats both outside and inside the home, if it is a multi-cat home. These circumstances presented more opportunities to become stressed.
Despite the plausible suggestion that stress is a factor, Dr. Bradshaw could not explain why they choose fabrics and why they actually ingest the material.
Reference book: Cat Sense by Dr John Bradshaw.