Lost Pet Research & Recovery

Tomcat with healed leg fracture.

Road traffic accidents (RTAs) are a common cause of injury and death for outdoor-access cats.  Olsen and Allen (2001) found that 51% of outdoor-access cats that suddenly and unexpectedly died were the result of RTAs, and Rochlitz et al. (2001) found that RTAs were the forth most common cause of death for cats after old age, cancer, and renal failure.  Based on the results of this study, Rochlitz (2003) conducted a more in-depth study to determine which factors may predispose cats to being involved in a RTA.  This study is particularly interesting because the results can be used to improve behavioral profiling of lost outdoor-access cats.

The cat’s age and sex were the two most important factors in determining whether s/he would be involved in a RTA.  Cats between the ages of 7 months to 2 years were most likely to be in a RTA and cats 6 years or older were less likely.  Overall, the likelihood of being in a RTA decreased by 16% for every year increase in the cat’s age.  Rochlitz (2003) suggests that this may be due to changes in the behavior of cats as they get older such as spending more time indoors, staying closer to home, and being more cautious.  Male cats were more than twice as likely to be involved in a RTA as female cats.  Due to small sample size, Rochlitz (2003) was unable to determine whether being spayed or neutered was a significant factor.  However, other studies have found that un-neutered male cats have much larger home ranges than neutered males or spayed or un-spayed females, which suggests they might be more likely to be in a RTA.  Rochlitz (2003) was unable to determine why males in general were more likely to be in a RTA than females, but males were found to spend more time outdoors than female cats.

The cat’s pedigree also affected whether s/he might be involved in a RTA.  Pedigree cats, mostly Siamese, Persian and Burmese in this study, were less than a third as likely to be hit by a car as domestic short-hair/long-hair cats or mixed breed cats.  The difference in risk for pedigree cats may be partly due to differences in the owner’s behavior and the cat’s behavior such as owners interacting with their cats more and cats spending more time indoors.

Other factors that were significant included traffic levels and whether the cat wore a reflective collar.  Cats were less likely to be in a RTA in areas with very low to low traffic levels and more likely to be in a RTA in areas with below-average to average traffic levels.  Strangely, cats living in areas with above-average to high traffic levels were not more or less likely to be hit by a car.  Another puzzling outcome of the study was that cats wearing reflective collars were more likely to be in a RTA.  Rochlitz (2003) was unable to determine a reason for this observation.

Almost equally important as the significant factors, Rochlitz (2003) also found that some factors did not influence whether a cat would in a RTA.  These factors included: coat color, whether the cat was allowed outside at night, season, the amount of time spent outside, and the time lived at an address.  Contrary to what was expected, dark colored cats and cats that were let outside at night, were not more likely to be hit by a car.  This particular study was conducted in Cambridge, UK, and surrounding towns, so the lack of seasonal differences may not be generalized to other areas of the world with different climates.  While amount of time spent outside was not independently linked to an increased risk of a RTA, cats in the high risk categories (i.e. young cats, male cats, and mixed-breed cats) all spent more time outside.  Time lived at an address was also strongly linked to the age of the cat and how much time s/he spent outdoors.  The sample of older cats that had moved (3) was really too small to determine if this was an influencing factor.

Rochlitz (2003) also attempted to measure some of the characteristics of RTAs.  Most RTAs (69%-80%) occurred just outside or very near the cat’s home.  However, this data may be biased because cats that were involved in RTAs farther from home may be less likely to be found by their owners’ and brought to a vet.  Rochlitz (2003) also attempted to determine what time of day/night most RTAs took place, but this analysis was inconclusive due to the large number of unknowns (47% of accidents).

Road traffic accidents are frequently a concern when an outdoor-access cat goes missing.  The results of this study help identify young (7 month – 2 years), male, mixed-breed cats as the highest risk group for RTAs.  Missing cats that fall into these categories should prompt a thorough search of the area around the home and immediate neighbor’s homes in case the missing cat has been involved in a RTA.  The results of this study also show that only 25% of cats involved in a RTA ended up dying.  These results may be somewhat biased since owners are probably less likely to bring a dead cat to the veterinarian, but they still show that many cats do survive being hit by a car.  This highlights the importance of thoroughly searching for the missing cat in case it is injured and hiding in silence.  More research needs to be conducted on the behavior of cats immediately after they have been in a RTA in order to improve our ability to find them.

To view a more detailed summary of Rochlitz’s (2003) two studies, follow this link to A Summary of a Study of Factors that may Predispose Domestic Cats to Road Traffic Accidents.

Literature Cited

Olsen, Tammy and Andrew Allen.  2001.  Causes of sudden and unexpected death in cats: a 10-year retrospective study.  Canadian Veterinary Journal 42: 61-62.

Rochlitz, I., T. De Wit, and D.M. Broom.  2001.  A pilot study on the longevity and causes of death of cats in Britain.  Cheltenham, BSAVA Congress Clinical Research Abstracts. p.528.

Rochlitz, I.  2003.  Study of factors that may predispose domestic cats to road traffic accidents.  Part 1.  The Veterinary Record 153: 549-553 & Part 2: The Veterinary Record 153: 585-588.

When an outdoor-access cat goes missing from its home range, this frequently means that something has happened to the cat to prevent it from returning home.  Death, injury or illness may all prevent a cat from returning home.  When sick or injured, a cat may hide within its home range and may die if not found.  This behavior has been observed in both outdoor-access and indoor-only cats.  Understanding the frequency of different causes of death in owned cats (particularly sudden death where the owner does not know that the cat is sick or injured), may help us better determine priority areas to search for a missing cat.

Olsen and Allen (2001) conducted a study on sudden and unexpected causes of death for cats in a city of over 200,000 people and surrounding towns in Saskatchewan, Canada. During a 10-year period, one large veterinary facility treated 994 cats of which 79 (8%) were brought in for autopsies by their owners because they died suddenly and unexpectedly.  Of these 79 cats, 49 (62%) were outdoor-access, 11 (14%) were indoor-only, and 19 (24%) were unknown.

Table 1. Underlying causes of sudden and unexpected deaths in 79 cats.

Table 1 shows the relative frequency of different causes of sudden death.  By far the most frequent cause of sudden death (34%) was attributed to trauma caused by road traffic accidents (RTAs).   All but two of the RTA deaths were outdoor-access cats, so that means that 51% (25 out of 49 total) of outdoor-access cat deaths were due to RTAs.  Other types of death due to trauma were 3 dog bites and 1 gun shot.

Heart disease (20%), primarily hypertrophic cardiomyopathy, was the second most frequent cause of sudden death followed by intestinal disease (8%).  Five of the 6 cases of intestinal disease were under six months old and died of enteritis due to feline panleukopenia.  Surprisingly, three of these kittens were indoor-only.  Respiratory disease accounted for 6% of deaths; three of these cats died of pneumonia and were 2-10 months old.  The other two cats died from breathing obstructions.

Urinary tract diseases (5%) were more likely to occur in older cats.  Three cats aged 8, 10, and 18 years died of renal disease.  One 6 year old cat died of a urethral obstruction.  This is unusual only because urinary obstructions usually have visible symptoms such as frequent urination or straining prior to death.  Diseases associated with feline leukemia virus (FeLV: 4%) were the last relatively frequent cause of sudden death.  All three FeLV-related deaths were outdoor-access cats.  The remaining four causes of sudden death all accounted for few cats (1% each).  The cause of death could not be determined in 13% of cases.

In this particular study, road traffic accidents accounted for a high percentage of deaths (51% of outdoor-access cats autopsied).  This number is even likely to be an underestimate because the data were collected from autopsy reports.  If a cat was obviously hit by a car, its owner would probably be less likely to go through the expense of getting the body autopsied.  There were also no cases of poisoning or death by predators, besides the three presumed dog bites.  However, predator deaths may also be underestimated since these bodies are less likely to be recovered.

Unfortunately, since Olsen and Allen (2001) did not collect data on the entire population of cats in the study area, it is not possible to determine whether certain characteristics (e.g. age, sex, access to outdoors, etc.) may predispose cats to different causes of sudden death.  In upcoming blog posts, I intend to focus on the most common causes of sudden death and find out what is known about them.  The first paper I’m going to review is a very informative study on the factors that may predispose domestic cats to road traffic accidents.

Olsen, Tammy and Andrew Allen.  2001.  Causes of sudden and unexpected death in cats: a 10-year retrospective study.  Canadian Veterinary Journal 42: 61-62.