A new study looks at pica and chewing behavior in cats.

Does your cat like to chew on things that aren’t food? If so, you are not alone. I personally have had cats who liked to chew paper (one cat shredded my rent check once), cardboard, corners of the carpeted cat tree, and the ever-popular plastic bag. Have you ever wondered WHY your cat does this?

When an animal ingests non-food items, that behavior is called pica. Humans do it too, with the most common targets being dirt or paint (yum!). The cause is not well-understood, with nutritional deficiencies, parasites, need for fiber, and obsessive-compulsive disorders all being tossed into the ring of possible reasons.

A new study, “Characterization of pica and chewing behaviors in privately-owned cats: A case-control study,” tried to get a handle on some of the factors that characterize pica in housecats. Previous research has suggested an influence of breed on the ingestion of fabric, with oriental cat breeds showing a predilection toward fabric-chewing and ingestion. Others have suggested that being housed indoors only is a factor, pointing to boredom and stress as a possible cause.

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

The current study surveyed owners of cats with pica (N=91) alongside a control group of owners whose cats were not reported to have ingestion disorders (N=35). Owners were asked many questions about the cat (such as age, sex, breed), as well as questions about the household (people in the home, other pets, what types of enrichment such as toys and perches were available), and whether the cats had access to the outdoors. The researchers also asked questions about the presence of other behavioral issues as well as gastrointestinal disorders (from farting to vomiting). Perhaps importantly, they also asked owners if the cats ingested or just chewed on non-food items, and if so, what kinds of objects they liked to chew or eat.

Results suggested that in cats with pica, there were two types: specialists and generalists. Specialists preferred one type of item to ingest, while generalists had several things they liked to eat besides food. The most common targets were shoelaces/thread, plastic, fabric, rubber, or paper/cardboard. Some cats also enjoyed snacking on ear plugs, tape, toilet paper, sponges, and fabric softener sheets.

This cat has spent some time chewing on the cardboard box. Photo via Flickr/Creative Commons by Dwight Sipler.
This cat has spent some time chewing on the cardboard box. Photo via Flickr/Creative Commons by Dwight Sipler.

Surprisingly, the study demonstrated that many cats are “chewers” – of all the cats in the study, 70% of the pica cats and 60% of the control group chewed on non-food items, even if they didn’t ingest these items. Seventy-three percent preferred plastic, with 61% enjoying chewing on paper, and 45% chewing on rubber.

Although both pica and control cats like to chew, there were some differences between the two groups. Control cats were more likely to have food available at all times; pica cats were more likely to show more self-grooming behavior; pica cats were more likely to have access to the outdoors; and pica cats were reported to vomit more frequently than control cats.

These findings suggest many questions for further study. First of all, why so much chewing? One possibility is that, as hunters, cats would be spending a lot of time chewing and crunching through the flesh and bones of mice, birds, and other small creatures. Research has suggested that the act of chewing may activate areas of the cat’s brain that are serotonergic (meaning releasing and responding to serotonin), hinting that chewing might have some “feel good” properties for cats.

Cats love plastic bags...to sit on or to chew. Photo via Flickr/Creative Commons by Mr TinDC.
Cats love plastic bags...to sit on or to chew. Photo via Flickr/Creative Commons by Mr TinDC.

Why is plastic so popular? No one really knows. Some have suggested that some of the ingredients used for making plastic may be appealing, or that perhaps the sound of the bag crunching is somehow satisfying. I recommend playing it safe, and keeping plastic bags out of reach of your cat.

Is hunger a cause of pica? Cats exhibiting pica were more likely to be fed on a schedule. While scheduled feeding can have its benefits, such as weight control, cats are used to eating several small meals throughout the day. Future research needs to look at the pros and cons of scheduled feeding for cats, and how feeding regimen might interact with other household variables (such as use of food puzzles, exercise and enrichment options, and social factors, such as how the food is dispensed to the cat).

Many of the pica cats were vomiting frequently. It is possible that pica is related to digestive disorders or discomfort – and that the chewing is an attempt to relieve discomfort. Since this was a survey-based study, we don’t know if any of these cats were under treatment for vomiting (especially given that many people think vomiting is normal in cats – but frequent vomiting is a sign that your cat needs to see a vet). Another question for future exploration – the interplay between pica and gastrointestinal issues.

Cat grass can be a healthy option and serve as enrichment for some kitties. Photo via Wikimedia Commons.

If your cat is a chewer, take note: accidental ingestion of non-food items by your cat can lead to expensive surgeries, or even death. While it might seem odd or cute, this behavior merits close attention to ensure that your cat is not injuring himself while chewing. Be sure to mention this behavior to your veterinarian, and try offering your cat plenty of appropriate and safe chewing options: cat grass, dental kibble from a food puzzle, and chew toys are all good places to start!

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All weekend long! #SPARCS2015

Once a year or so, there's a canine science conference, and it's happening again this weekend. You can live stream the whole thing FOR FREE!!! DO IT!! Or at least drop in for a few talks. This year's speakers include Katheryn Lord, Hal Herzog, James Ha, and my friend @DogSpies will be there too!

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A power outage like no other

I have reported on plenty of squirrel-related power outages before, but the one that hit my own town (Berkeley) has gotten a lot of attention, perhaps because of the huge number of people impacted. Coincidentally, while I was in New York, I got a call from the New York Times to talk about it. Although a squirrel may seem like a scapegoat...this is how the power company knows a squirrel did it...a body is usually left behind.

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Evolutionary Arms Race for...egg patterns?

Brood parasitism occurs when a bird of one species lays its eggs in the nest of a different bird. If the nesting bird can't tell the difference between its own babies and someone else's, the best thing to do is just...take care of them! To improve their sneakiness, the parasite has evolved to lay eggs that are more similar to the hosts...but in return, scientists have now discovered that the host has evolved to lay more complexly patterned eggs, to make it easier to kick out those foreign eggs.

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I've reported on many power outages caused by squirrels, and now I have been the victim of one.

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Cats and Squirrels is off to the Big Apple for a six-day-vacay! Back next week!


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Human Vs. Squirrel: It’s a Never Ending Battle

Squirrels can get into enough trouble on their own, but somehow, involve a human, and someone is going to get hurt (usually the human)

Someone made the mistake of offering his hand to a squirrel in the Grand Canyon. The squirrel bites him. Then a bunch of other tourists try to pet the same squirrel. Just sayin.’

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This man went to claim his bicycle, only to find a squirrel with the same idea in mind. The squirrel made a go for his GoPro, too.

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And for the second time in a few weeks, a squirrel has “gone wild” in the NY subway system. They must know I'm headed there.

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Don’t feed the squirrels

The red squirrel is endangered and under protection in the UK. Now experts are concerned that those who are trying to care for them (by feeding them) may be spreading the squirrel pox disease due to dirty feeders spreading contagions.

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manBut one local man is upset, and wonders how the population can rebound without his help.







Do you brake for squirrels?

brakeA new ad campaign in the UK is encouraging drivers to slow down and watch out for the red squirrel. While the primary threat to these little guys is the invasive gray squirrel, turns out that a lot of them get squished by vehicles each year.


Well perhaps you shouldn’t

A man caused a four-car collision when he braked to avoid hitting a squirrel crossing the road. No one was hospitalized, including the squirrel, but there were some damaged cars.

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Power Outages

Squirrel-related power outages were reported in Bay City, MI, and Sanford, MI.

Over six thousand folks in Knoxville, TN were left without power thanks to a squirrel, and

somehow a bird AND a squirrel were in cahoots in Topeka, KS, leaving 5000 people in the dark.

Finally, a squirrel was found dead on the sidewalk after it sparked a power outage and a house fire in Franklin, LA.

This week in cute

Twirling squirrels

I admit to having mixed feelings about the Twirl a squirrel – yet every time I see a video of a squirrel stuck on one, I find myself laughing hysterically.

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Want to do your own squirrel photo shoot?

The secret to great squirrel photos? Peanut butter. More tips here!

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The squirrel’s point of view

What if a squirrel had a camera? Perhaps this is the same squirrel that attacked the bicyclist’s GoPro. This squirrel carries a camera up into a tree (does he think it is food?), allowing a lovely (if not, shaky) glimpse into how a squirrel sees the world.

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Urinary tract problems are relative common in cats - approximately 1.5% of cats who go to the vet are treated for them. But the majority of those problems don’t appear to have a specific cause, so cats are often diagnosed with “feline idiopathic cystitis (FIC)” – the term idiopathic meaning that disease process is of unknown origin. I’ve previously reported on the link between stress and litterbox issues in cats; and the relationship between cystitis and stress in humans and cats appears to be a strong one. But what might cause stresses in cats that would lead to urinary tract disease?

A new study from Norway, “Risk factors for idiopathic cystitis in Norwegian cats: a matched case-control study” sought to find out what type of environmental or personality characteristics might put cats at risk for FIC. The authors surveyed 70 folks whose cats had been diagnosed with FIC and as a control, surveyed 95 cat owners whose cats were patients at the same veterinary hospital, but had never shown signs of urinary tract problems. Owners were asked several questions about the cat’s environment, personality, how the litterbox and food/water stations were maintained, and the cat’s opportunities to express species-specific behaviors (such as scratching, play, and perching up high). Seventy-one percent of the FIC cats were males, and most were domestic short-haired cats.

There are a lot of obese kitties out there. Photo by Psyberartist via Flicker/Creative Commons.
There are a lot of obese kitties out there. Photo by Psyberartist via Flicker/Creative Commons.

Cat-related factors that appeared to be related to an FIC diagnosis included obesity or being overweight (51% of the FIC cats compared to 32% of controls), and fearfulness (36% of the cats with FIC compared to 24% of controls). The only contributing household variable was being kept indoors only, which increased the likelihood of being diagnosed with FIC. Fights with cats outside (or even just the presence of cats outside) did not appear to be a factor.

In addition to weight being a factor, how cats were fed was different between the FIC and control groups, with more FIC cats being on a scheduled feeding regimen, instead of being free fed. There was a tendency for FIC cats to have food and water dishes and litterboxes in less “safe or comfortable” areas. The authors concluded that obesity (and the likely lack of exercise that accompanies it) may have indirect effects on stress. Meal feeding may also be a source of stress, as it may force cats to eat in proximity of other cats, and at a schedule that does not reflect their natural hunting schedules (which would likely include several small meals throughout the day).

scared stardust
Fearful cats may be susceptible to FIC. Photo by Dilara Goksel Parry.

I’m always interested in what these studies reveal about how people meet the needs of their cats (regardless of the original research question). Large numbers of cats in both groups showed nervous or fearful behavior. Why? Is this because of a chaotic environment, lack of appropriate safety, poor socialization, or something else? One-third to one-half of cats in the study were reported as overweight or obese! Around twenty-five percent of cats fight regularly with neighboring cats, and around sixteen percent of all cats in the study are often injured from these fights. These reports suggest a sub-optimal social environment for many cats.

How about the physical environment? Around 16 percent of owners in the study placed the food and water dishes in the same location of the litterbox (do YOU want to eat in your bathroom?). Sixty percent of owners cleaned the food and water bowls regularly, but only around half of all cat owners in the study scooped the litterbox daily. Fewer than five percent of owners provided the recommended number of litterboxes (one per cat plus one) in their home. The good news is that over 90% of cats in the study had a scratching area, and over 85% had some type of climbing structure or elevated “vantage point.” Around 65% of cats in both the FIC and control groups were reported as having high levels of playful activity.

So, this study provides us with some insight on potential contributors to FIC in cats, as well as a snapshot of the life of a Norwegian kitty. I think there is always room for improvement in making cats happier when they are stuck living with us – whether that means more mental stimulation, exercise, cat-related resources, or owner education. I think that Norwegian pet owners are probably not so different from their counterparts in other countries, meaning that we might have quite a few scared, fat, stressed-out kitties living in homes throughout the world. And until that changes, my work isn’t done!


Heidi S LundBente K SævikØystein W FinstadElin T GrøntvedtTerese Vatneand Anna V Eggertsdóttir, Risk factors for idiopathic cystitis in Norwegian cats: a matched case-control studyJournal of Feline Medicine and Surgery 1098612X15587955, first published on May 27, 2015doi:10.1177/1098612X15587955

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For the birds!

3D printing is changing science!

We often hear the results of the studies, but not about all the challenges of actually conducting them! One lab that studies birds that lay eggs in other species' nests (known as brood parasitism) in the past had to make their "fake eggs" by hand, using plaster of paris - making it difficult to make every egg exactly the same. 3D printing has now made it possible to save time, make better experimental stimuli, and still fool those birds.

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How do you find a good nut?

If you're a bird, you might want to know if that peanut is a good one. Mexican Jays use head movements (very similar to those made by squirrels) to weigh peanuts, and use this information to choose heavier ones to eat.

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Dinosaurs: More like mammals than we realize?

Were dinosaurs actually warm-blooded? A reanalysis of dinosaur growth data that treats birds and dinosaurs as part of the same "family" (since birds are considered dinosaurs) suggests growth patterns of an "intermediate" category - somewhere in between warm-blooded and cold-blooded.

Contagious yawning: Not just for primates

budgiesIf you yawn when someone else near you yawns, you're not alone. Contagious yawning is considered a primitive form of empathy. That's why we thought only primates did it, you know, all that "humans are special" stuff? A new study demonstrates contagious yawning in budgies, a highly social, intelligent parrot.






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Squirrels and crime

A man told a couple that squirrels had damaged their roof and he’d be happy to fix it…just pay up front please! The couple got some cash, the man took it, and needless to say, no squirrels were actually involved.

A squirrel in NYC bit a subway worker when she tried to shoo him away…perhaps the squirrel was late for his train? Paramedics took the worker to the hospital for treatment.

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Several animals, including a gray squirrel, were seized from a couple in Savannah, Georgia. Police had a search warrant, although it’s not clear why.

...continue reading

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When you are in pain, how does your doctor know where it hurts? You usually have to tell them. You might draw on an image of a body exactly where you are experiencing pain, or rate your pain on a scale. Pain is typically described as an unpleasant sensation, with physical, emotional and cognitive components.



When an animal is in pain, can we tell? Maybe. For some animals, there might be clear signs of pain, such as an obvious injury. In the “old days” philosophers such as Descartes did not believe that animals felt pain, even if they had an injury; it is only in the last 30-40 years that scientists have acknowledged the likelihood that animals (particularly other vertebrates) feel pain, and that we should behave under the assumption that they do.

cone of shame
Injuries are an obvious source of pain and may lead to the "cone of shame."

There may be some obvious indicators of pain in animals, such as refusing to put weight on a limb, or avoiding contact with a potentially pain-inducing stimulus, such as a hot stove. But there may be other less obvious indicators, such as changes in facial expression or posture, or changes in personality or appetite. With cats, pain detection can be even trickier, as we assume that as prey animals, cats are likely to hide indicators of pain and discomfort that might make them vulnerable to attack. We also know that humans often have difficulty reading their cats’ body language, including that which might suggest pain. The conclusion that follows is that cats are typically UNDERtreated for pain. So what DO we know about determining pain in cats?

Recently, two scientists, Isabella Merola and Daniel Mills, at the University of Lincoln conducted a meta-analysis/review of the last 15 years of research involving the assessment of pain in cats (“Systematic review of the behavioural assessment of pain in cats”). The goals were to assess the current tools in use and identify future areas for research. One hundred studies were reviewed, with each being assessed for method of measuring pain, whether measures were objective (behaviors) versus more subjective (inferring states, such as “the cat looks happy” or “peaceful”), and whether they assessed immediate emotional response to the pain or looked more at the cats mood or personality changes. They also assessed the validity and reliability of the tools – did they measure what they claimed to measure, and would they lead to reasonable agreement between raters?

Most of the studies were assessing cats after a surgery such as spay/neuter, or (the incredibly painful) declaw surgery, or during a repair of a fractured bone. From these studies, Merola and Mills were able to identify the types of tools used to assess pain in cats. These included scales, which might ask a rater to measure assumed pain intensity on a scale, or with specific definitions (such as lameness or response to touch). Another type of tool would provoke pain (via heat, pressure, or electricity) to see what level would lead to withdrawal by the cat. Many of these tools did not define behavioral reactions that would suggest pain aside from withdrawal responses. Scales were the most commonly used tools, but few of them reported on their validity or reliability measures (one that did: the UNESP-Botucatu scale).

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Other types of tools were based more on subjective reports from the owner, behavioral observations by a researcher, or an assessment of how much a cat was inhibiting movement. Some of these tools included behaviors that would indicate both the sensory experience, and an emotional component – such as vocalizations, skin twitching, tail movements, paw shaking, sleep, and posture.

Vocalizations may be an indicator of pain in some cats.
Vocalizations may be an indicator of pain in some cats.

Tool use seemed to fall into two categories: use of scales for acute, provoked pain (such as surgery) which focused on the sensory experience of pain, or scales used for chronic conditions, which heavily focused on those emotional components. The process of differentiating when acute pain becomes chronic was not clear; the timescales used in the studies reviewed appeared to be inconsistent and somewhat arbitrary.

This manuscript also revealed a few important things: these tools have been assessed in very few contexts (primarily surgery and serious injuries), yet there are several conditions that may cause acute or chronic pain in cats, including arthritis, stomatitis, inflammatory bowel disease, pancreatitis, and many other illnesses or injuries.

Image from E. Holden, G. Calvo, M. Collins, A. Bell, J. Reid, E. M. Scott,, A. M. Nolan
Cat face scale shownig ear and muzzle changes in cats in response to pain. Image from E. Holden, G. Calvo, M. Collins, A. Bell, J. Reid, E. M. Scott,, A. M. Nolan, Journal of Small Animal Practice

Because some of the assessments required interactions with cats that could be stressful or scary, the authors suggest that observational tools and behavioral methods are the way to go. These types of tools, with owner education, could increase the likelihood that owners would recognize and report signs of pain in their pet cats. One of the more exciting recent studies on assessing pain in cats, Evaluation of facial expression in acute pain in cats, suggests that cats in pain have statistically distinct facial expressions, with changes in both the ears and muzzle. Unfortunately, most observers had a hard time detecting these differences.

Even with the 100 studies included in this review, there are still many unanswered questions. Merola and Mills point to a few key directions for future studies, including defining acute versus chronic pain, and relying more on observation than inference. Assessment tools need to be tested in several potentially painful contexts to make sure they are universal in scope.

So back to my original question, why is pain detection so difficult in cats? I think there are a few reasons: sometimes the more you research something, the more obvious it is how little we know about that thing (in this case, how to measure feline pain). Consider that cats might hide pain, and that there have been many different tests and approaches. Let’s hope this important review helps researchers focus and unify their methods!

For examples of other pain scales currently used for cats:





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Goldfish vs. Humans: But can they multi-task?

Every now and then I find a click bait study pretty amusing. A new study (including measuring human brain activity) finds that over the last 15 years or so, our attention spans have gotten even shorter (from 12 seconds to 8 seconds). The culprit? Perhaps cell phones and the huge amount of information we try to take in by staying "connected." Goldfish, who haven't been impacted by changes in technology, are still holding strong with 9 seconds of attention to give to a task. The Onion had something to say too.

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...continue reading

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It's been over a month since I updated you on squirrel news, and it appears that squirrels have been very busy since then.

Squirrel Damages

The historical Derby Summer House in Massachussetts is in critical state, due to damage ccaused by squirrel chewing. Subsequent water damage and squirrel poo equals over $200K in repairs needed to be done.

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Squirrels also seem to like a Nebraska City building that houses the passport office and juvenile services. Nests and squirrel poo were found above the ceilings throughout the building, leading to a major cleanup and remodel.

A house fire near Chicago was caused by a burning squirrel nest in the attic: was the squirrel drunk and smoking in the nest?

A driver swerved to avoid a cat chasing a squirrel and hit a fire hydrant. No word on if the cat or squirrel were okay.

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People were not so lucky in Florida, where a squirrel caused four car pile-up and a death, after a driver stopped in traffic to avoid hitting the rodent.

Squirrel-related deaths in history: 60 years ago a boy was killed by squirrel poison on a Northern California island.

Adding to the list of diseases that squirrels may carry (such as West Nile and the Plague…) squirrels have now been identified as carriers of Lyme disease. And this is just one reason you should not pet wild squirrels!

...continue reading

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