Chew on this! A new study looks at pica in cats

Pica, or the ingestion of non-food items, is found in species as varied as parrots, humans, and domestic cats. It’s unclear why some animals eat things that aren’t food – some guesses include stress and nutritional deficiencies. This behavior in cats was first noticed in Siamese cats, who are prone to sucking and eating woolen items. However, once all breeds (including the domestic shorthair) were included in studies, it became apparent that this behavior isn’t limited to the meezers in any way.

A new study, Characterization of pica and chewing behaviors in privately owned cats: a case control study, sought to better understand factors that might predict pica in cats, in the hopes of helping the veterinary community in developing effective treatments. This study surveyed 91 pet owners with cats who ingested non-foods, and included a control group of 35 cats who did not.

The researchers asked questions about basic kitty demographics, including age, breed, sex, medical history. They also included questions about the environment (including types of enrichment available, other people and animals in the house, and access to the outdoors). Finally, they asked questions about potential gastrointestinal signs, such as vomiting and diarrhea.

Some cats are attracted to eating strings and shoelaces. Photo "Cat on a strong" by Stefan Tell via Creative Commons/

All cats in the pica group ingested non-food items, with 79 of them also chewing (but not swallowing) other things on a regular basis. Twenty one out of thirty-five of the control cats (that’s 60%) also chewed on things that aren’t really chewables!

What do cats with pica like to “eat?” Perhaps not surprisingly, shoelaces, plastic, and fabrics were all in the top three. Other interesting choices included toilet paper, soap, ear plugs, kitty litter, and sponges. Plastic, paper, rubber, and wood were the chew-toys of choice for the cats who were chewing on items.

Three variables were prominently related to the presence of pica – the first was access to the outdoors. Although pica in cats has often been blamed on being kept indoors and bored, in this study, the pica cats were MORE likely to have access to the outdoors.

Fifty-one percent of the control cats had “ad libitum” access to food – meaning that food was freely available. This was only true for 30% of the pica cats, even though there were no differences in feline hunger ratings by owners between the two groups. Does having food freely available redirect some of that chewing behavior toward food?

Finally, more vomiting was found in the pica cats – but we have a chicken and egg problem in that we don’t know if the vomiting is caused by the chewing, or the chewing is an attempt to relieve nausea. This manuscript opens up interesting research questions about the behavioral signs of gastrointestinal disease, but also suggests that pica is not (at least in all cats) necessarily a stress-related or compulsive disorder caused by indoor housing.

The choices for chewing and eating are interesting to me – we still don’t know why things like plastic and fabric are so darn attractive to cats. And soap? Really? And although we don’t know the prevalence of true ingestion of non-food items in the general population of cats, it’s apparent that chewing behavior in cats is very common (60%) even in a control group of cats!

Pica in cats can be dangerous – in some cases, it can lead to expensive surgeries for gastrointestinal blockage. Pica and chewing can also cause damage to your war

Some cats love to chew on things that aren't food...why? Photo via Flickr/Creative Commons by Jessica Fiess-Hill
Some cats love to chew on things that aren't food...why?
Photo via Flickr/Creative Commons by Jessica Fiess-Hill

drobe, but of course, the burning question is – what does it mean? Is pica a sign of emotional distress or physical pain? Is it a nutritional deficiency? Is it brain chemistry gone awry?  Do cats just need appropriate chew toys? Still so many questions!

If you see your own kitty chewing or eating something that isn’t food, be sure to let your vet know before you have an emergency on your hands! In the meantime, this study chips away at the pica mystery, and brings up some interesting questions about how we feed and house our cats.

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4 thoughts on “Chew on this! A new study looks at pica in cats

  1. Thanks for another great article, Mikel! Out of my five cats, I have one who LOVES to lick plastic grocery bags and ziploc baggies. She doesn't eat them, but it's very curious! Anyway, pica has always been a mystery to me, and I generally treat it as a stress-related disorder. The results of the study you cited are interesting in that pica is not necessarily indicative of stress related to being kept indoors! The mystery continues, I suppose... 🙂

  2. Elizabeth Fox

    Our cat licks the couch, eats our straw that is in our drink, and eats our dental floss right out of our hands as we are flossing our teeth. When I learned about pica, I found a 1991 article, Feeding and Drinking Behavior Problems, that indicates pica in cats might be due to early weaning. The new articles suggests pica is not due to early weaning, and we suspected new research would contradict the 1991 article.

    1. Mikel Delgado

      Post author

      things are usually more complicated than we think! I think pica is a good example of that.


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