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“Tom”, an 8-month old male domestic shorthaired kitten,
presented to my hospital with a complaint of lethargy
and unusual ingestive behavior. According to his owners
Pat Galloway and Peter Webb, the normally rambunctious
kitten had become lethargic over the past two days,
spending most of his time sleeping. The cat’s appetite
had markedly decreased, although he was still gaining
weight nicely and was a healthy 8 ½ lbs. They also
reported that Tom had been seen eating his clay cat
litter and licking the floor around his litter box.
Physical examination revealed pale gums, and a quick
in-house test confirmed that Tom was severely anemic.
Additional tests showed that Tom’s bone marrow was not
properly compensating for the anemia by producing more
red blood cells, suggesting a primary bone marrow
disorder. Tom was given a life-saving blood transfusion,
and a bone marrow evaluation was performed soon
afterward. Tom was diagnosed with pure red cell aplasia
(PRCA), a severe form of anemia that is believed to
result from an immune system disorder. High doses of
immunosuppressive drugs were prescribed, and Tom’s red
blood cell count increased steadily over the course of a
few weeks. Meanwhile, Pat and Peter had quickly switched
from clay-based to wheat-based litter, in an attempt to
discourage Tom from eating his litter, as clay litter
contains bentonite which can form a hard clump in the
intestines, leading to obstruction. The switch worked;
Tom stopped nibbling on his litter.
As the anemia came under control, an attempt was made to
try to reduce Tom’s medication dose. Eventually, his
condition was maintained on every other day therapy, and
Tom appeared healthy.
Three months later, however, Tom presented to my
hospital with a complaint of a gradual onset of lethargy
and decreased appetite over the past week. Pat and Peter
also reported an unusual new behavior: Tom had begun
licking the silverware. Physical exam and blood tests
revealed that Tom’s condition had relapsed. Fortunately,
he responded well to another transfusion and to an
increase in his medication, and Tom is now back to
normal; no more anemia, and no more licking of the
silverware.
“Pica” (pronounced “PIE-kuh”) is the voluntary ingestion
of non-edible materials. The term comes from the Latin
word “magpie”, because magpies are said to eat almost
anything. Pica accounts for approximately 2.5% of
abnormal behaviors in the domestic cat. The etiology of
true pica is not known, although mineral deficiencies or
psychological disturbances are often blamed. Tom’s case
is interesting in that his pica – eating litter and
licking silverware – seemed to be clearly connected to a
medical disorder (his anemia).
Wool-sucking is a commonly described abnormal ingestive
behavior in cats. Wool-sucking, however, is a
compulsive, misdirected form of nursing behavior and
technically should be distinguished from true cases of
pica.
“Kittens nurse fairly actively for the first seven weeks of
their lives, with mom rebuffing them at the latter end
of the period in order to ‘teach’ them to fend for
themselves”, explains Dr. Nick Dodman, Director of the
Animal Behavior Clinic at the Cummings School of
Veterinary Medicine at Tufts University, and author of
book The Cat Who Cried for Help. “’Comfort nursing’
(running to mom for a couple of quick sucks even when
the milk bar is dry) is normal kitten behavior, even up
to 6 months of age. As the kitten grows older and shifts
its preference to solid food, the drive to nurse fades.”
If, however, this natural progression is disrupted by
abrupt early weaning while the kitten’s nursing drive is
still very powerful, the kitten may displaces its
nursing onto substrates that look or feel like mom.
“They may begin sucking on themselves, their
littermates, or certain wooly materials, especially wool
itself”, says Dr. Dodman. Human infants show similar
behavior when they suck their thumbs or a pacifier. In
general, the younger a kitten is when it is weaned, the
stronger the nursing drive, and the more persistent this
non-nutritional sucking may become.
Wool sucking usually fades over time as the kitten
develops other interests. For those kittens whose wool
sucking has apparently faded into oblivion, however,
vague memories of this behavior may persist throughout
life, and in moments of stress or conflict, it may
resurface as a comfort behavior. In some cases, it may
assume compulsive proportions. In other cats, wool
sucking doesn't resurface, possibly because serious
conflict does not arise.
Wool sucking is usually not a problem, “especially if
the behavior remains at the ‘wool sucking only’ stage”,
says Dr. Dodman. Some cats, however, progress to
actually eating the non-nutritional materials,
predisposing the cat to potentially serious problems
such as gastrointestinal obstructions.
Such was the case with Pumpkin. Many years ago, while
working for a feline-exclusive veterinary practice in
Baltimore, I was presented with a big 4 year-old orange
male tabby. The complaint was poor appetite and vomiting
of three days duration, and before I could even start my
exam, Pumpkin’s owner warned me that Pumpkin had always
had a penchant for plastic bags. Three years prior,
Pumpkin had a plastic bag surgically removed from his
stomach, and his owner was having that unmistakable
feeling of déjà vu. Sure enough, x-rays revealed the
presence of something odd in Pumpkin’s gastrointestinal
tract, and during exploratory surgery, a sizeable chunk
of a plastic grocery bag was extracted from Pumpkin’s
intestine. Fortunately, Pumpkin recovered uneventfully.
An attraction to plastic is a common scenario
encountered by feline practitioners. Exactly why cats
like plastic remains unknown, although several theories
abound. Some people have speculated that cats like the
coolness of the plastic, or the texture on their tongue,
or perhaps the sound it makes when they lick. The most
logical reason I’ve heard, however, is that cats like
licking or eating plastic bags because rendered animal
fat (also called “tallow”) is utilized during the
manufacture of some plastic bags, and that some cats can
detect the smell and enjoy the taste. Other versions of
this explanation have implicated petroleum products and
gelatin as the enticing ingredients. Gelatin, in fact,
is used in the manufacture of many items including the
emulsion used in photographs, which may explain why my
own carnivorous cat, Emma, enthusiastically licked clean
all of my unattended family photos one afternoon. I’ve
never been able to confirm the tallow-petroleum-gelatin
theory, so CatFancy readers should not take this as the
gospel truth. But it sure makes sense to me.
Because pica can be a sign of an underlying medical
problem, like Tom’s anemia, cats displaying unusual
ingestive behavior should be examined by a veterinarian.
Certainly, cats with unexplained gastrointestinal
symptoms and a history of eating unusual objects should
be examined right away, and clients should inform the
veterinarian if the cat has a known tendency toward
dietary indiscretion, since GI obstructions may be
life-threatening. Pica might seem like charming, quirky
behavior, however, because of the potential harm from
eating non-nutritional material, cat owners should
discourage this behavior.
Updated
7/26/06 |
