Fabric chewing and eating in cats may be the equivalent of thumb sucking in infant humans. The process is soothing and may occur when the cat is stressed. Babies suck their thumbs to soothe themselves.

Siamese, Burmese and the Oriental cat breeds are known to be susceptible to engaging in a particular form of pica which is the eating of non-nutritional substances.

Lilac Siamese eating wool. Photo: copyright Warren Photographic

Although some random bred cats have versions of pica such as chewing on elastic bands, a proportion of pedigree Oriental cats chew and sometimes eat fabrics. Their favourite is wool. Cotton and synthetic fabrics are less popular.

The cat starts by chewing on the fabric and then eating the chewed bits that have fallen off. It looks like the cat is treating wool as a food.

Dr Bradshaw in Cat Sense writes that he has seen a Siamese cat drag an old sock onto his food bowl and then alternately eat the food and then the sock.

The theory is that as fabric sucking purebred cats come from a certain genetic pool this abnormal behaviour is likely to be inherited. However, in tests Dr Bradshaw writes that the behaviour does not seem to be inherited directly. Neither did tests confirm that the fabric eating infants where imitating their mothers.

Apparently, for Oriental cats, the chewing and eating of fabric may set in a few weeks after being rehomed which indicates its link to stress. This behavior can also happen when the cat is about a year old even when his environment has not changed. This may be linked to stress again as at this age the cat is becoming sexually mature and entering into conflict with other cats for territory.

Another now redundant theory behind fabric eating was that the cats had a craving for the natural lanolin in the wool. Dr Bradshaw has disproved this in tests.