Fast facts about the "feral cat problem"

Feral, stray, and free-roaming cats

What’s the difference between feral, stray, and community cats?


Although the terms feral and stray are often used interchangeably, feral generally refers to unowned, free-roaming cats, especially those who are not socialized to humans either because they have never had human contact or because they have, over time, reverted to a “wilder” state in the absence of human contact. Stray, on the other hand, generally refers to owned cats (i.e., pets) who have become lost or displaced from their homes or property. The term community cat is less precise, but is typically used to refer to unowned, free-roaming cats regardless of their sociability. Free-roaming refers to outdoor cats, whether owned or not.

These categories are rather fluid — an indoor-only pet cat can, for example, slip outside, thereby becoming a stray and perhaps even a feral cat. This same cat could eventually become part of a TNR (trap-neuter-return) colony, warm up to a colony caregiver, and become a pet cat again.

It's important to note, too, that these definitions are not adopted globally and usage is often context-dependent. The law might define cats one way (e.g., domestic, feral, etc.), for example, while veterinarians, animal control officers, conservationists, etc., each categorize free-roaming cats differently.




How many feral cats are there in the U.S.?


Unfortunately, there are no rigorous estimates for the number of feral cats living in the United States. For years, various numbers have been quoted, but there’s been little to no empirical evidence to back them up. The best available estimate suggests that the population is probably about 32 million, roughly 76% of whom live in urban areas [1].

For more information, see What to do with feral cats: Examining TNR for population management.




Is the U.S. feral cat population increasing or decreasing?


Numerous media accounts suggest that feral cat numbers are increasing — though these stories never provide the kind of “before” and “after” data necessary to support such claims. Unfortunately, no studies to date have documented feral cat populations at a city or county level. However, an examination of data documenting the admission of cats to animal shelters across the county suggests that the number of feral cats, at least in urban and suburban parts of the country, is likely declining [1].




How quickly can cats reproduce?


One of the most frequently cited statistics associated with domestic cats suggests that two unsterilized cats and their offspring can produce 420,000 cats in seven years. This grossly exaggerates reality. It’s true that cats can begin to breed at six months of age [4,5] and produce an average of 1.5 litters (average of four kittens each) annually [3]. Lacking human intervention, though, many kittens born outdoors will not survive to reproduce. Taking this and other important factors into account, more realistic estimates put the figure at roughly 100–5,000 cats in seven years [6,7].

For more information, see What to do with feral cats: Examining TNR for population management.




How many feral cats are sterilized?


Results of the American Pet Products Association’s 2019–2020 National Pet Owners Survey suggest that 93% of pet cats are sterilized [2]. No comparable data is available for feral cat populations; however, studies reveal considerable variation in sterilization rates at the local level, from essentially 0% in areas where resources are scarce [8] to nearly 100% where intensive trap-neuter-return (TNR) programs are implemented.

For more information, see What to do with feral cats: Examining TNR for population management.




How long do feral cats live?


There’s little doubt that feral cats, on average, don’t live as long as pet cats, especially those living exclusively indoors. Although the often-heard claim that these cats live only about two years is supported to some degree by studies of unsterilized cats living without any apparent reliance on food from humans [9–11]. By contrast, studies have documented median lifespans for sterilized cats who were fed regularly (i.e., as part of “managed” trap-neuter-return programs) of 7–10 years and even older [12–14].

For more information, see Cat health and welfare after TNR: Considerations and concerns.




How many stray and feral cats end up in animal shelters?


Studies show that no more than seven of every 100 cats entering local animal shelters are reclaimed by their owners [15–17] (compared to 15–50% for impounded dogs [18]). One key reason for this is that, in many shelters, the majority of cats are brought in as “strays” with no owner to reclaim them [see, for example, 19,20]. For more information, see What to do with feral cats: Examining TNR for population management.




How many people feed stray and feral cats?


Results of the American Pet Products Association’s 2019–2020 National Pet Owners Survey suggest that 14% of U.S. households (and 26% of cat-owning households) provide care (mostly food and water) for “free-roaming cats” [21]. For more information, see Feral cat feeding bans: The reasoning, risks, and results.




How many pet cats go outside?


Results of the American Pet Products Association’s 2019–2020 National Pet Owners Survey suggest that approximately 68% of cat-owning households keep their cats indoors [2], nearly double the rate reported in 1997 [22]. Given recent estimates of cat ownership in the U.S. [1,2,23], this translates to approximately 22–24 million pet cats with at least some outdoor access.




Where do feral cats come from?


The term “feral cats” is used to describe unowned, free-roaming cats who are not socialized to humans either because they have never had human contact or because they have, over time, reverted to a “wilder” state in the absence of human contact. A common misconception is that a significant number of feral cats come from accidental litters by unsterilized pets, however, results of the American Pet Products Association’s 2019–2020 National Pet Owners Survey suggest that 93% of pet cats are sterilized [ 2], leaving only a small percentage of pet cats able to reproduce. Unfortunately, no comparable sterilization figure is available for unowned, free-roaming cats leading researchers to conclude that “feral cats likely represent the single most important source of cat overpopulation” [ 3]. In short, most feral cats come from other feral cats due to most feral cats not being sterilized.





Trap-neuter-return (TNR)

What is trap-neuter-return (TNR)?


TNR is a non-lethal technique for managing unowned, free-roaming cats. The cats are humanely trapped, spayed or neutered by a licensed veterinarian, ear-tipped (the universal sign that they have been sterilized), and returned to where they were trapped.

Many TNR programs also vaccinate cats against the rabies virus and three common viruses in cats (feline viral rhinotracheitis, calicivirus, and panleukopenia virus) through what’s known as the FVRCP vaccine. Programs that routinely vaccinate cats against rabies are sometimes referred to as trap-neuter-vaccinate-return (TNVR) programs, to emphasize this important public health component.

In addition, some TNR programs will find homes for adoptable cats and kittens (when doing so is feasible) and coordinate with designated caregivers who provide ongoing care for the cats (e.g., food, water, shelter, veterinary care).

For more information, see What to do with feral cats: Examining TNR for population management.




How big are feral cat colonies?


Free-roaming cats that gather in a particular area are often referred to as a “colony.” Research suggests that the size of a typical cat colony is fewer than 10 or 12 cats [34,27,35,28,36], and tend to be even smaller when most cats are sterilized [33,14].

For more information, see What to do with feral cats: Examining TNR for population management.




How long does it take for TNR programs to work?


Like any population management method, it takes time for trap-neuter-return (TNR) to result in population reductions. Numerous long-term (i.e., 10–28 years) studies have documented reductions of 30­–80% at the local level [24,12,25–28,14], as well as the elimination of cat colonies [14,27–29]. One- [30,31] or two-year [32] studies, however, tend to reflect the initial increases that can precede longer-term population declines [33], probably the result of a “reduction in agonistic behavior of the [sterilized] cats, resulting in a so-called behavioral vacuum” [30] that allows new cats to join existing colonies.

For more information, see What to do with feral cats: Examining TNR for population management.





Feral cats and public health

Do feral and stray cats spread rabies to humans?


Rabies in domestic animals was once relatively common; however, data compiled by the Centers for Disease Control and Prevention (CDC) show that nearly 93% of rabies cases in the U.S. now occur in wildlife [37]. Between 1975 and 2018 (the most recent data available), the CDC has documented 115 cases of human rabies in the U.S., most of which were attributed to contact with wildlife. Of the 26 cases attributed to domestic animals, 25 (96%) were attributed to dogs (nearly all exposures occurred outside the U.S.). Just one human case since 1975 was attributed to contact with a cat [38].

For more information, see Are stray or feral cats dangerous to humans and public health?




What are the most common causes of possible rabies exposure?


A national study of patients seeking treatment for possible rabies exposure found that 81% of exposures were attributed to dogs while 13% were attributed to cats [ 39]. One-third of dog exposures occurred in the public street or park, compared to 12% cat exposures; on the other hand, 24% of dog exposures occurred in the home, compared to 53% cat exposures [ 40]. These researchers also reported that most exposures, for both dogs (85%) and cats (92%), were provoked [ 40]. For more information, see Are stray or feral cats dangerous to humans and public health?





Feral cats and toxoplasmosis

Are feral and stray cats responsible for toxoplasmosis in wildlife?


Free-roaming cats have been implicated in the spread of toxoplasmosis to wildlife, in particular to marine mammals (e.g., California sea otters and Hawaiian monk seals) as a result of contaminated rainwater runoff [47,48]. However, research from the U.S. Geological Survey concluded that “spillover from wildlife, not pets” is likely responsible for infection in California sea otters [49], whose population is, in any case, near a 100-year high [50,51].

The population of Hawaiian monk seals, too, is on the rise, according to the National Oceanic and Atmospheric Administration — even in the Main Hawaiian Islands, where they were rarely seen before 1990 [52]. On one hand, this is surprising since these are the most densely populated of the Hawaiian Islands (by both humans and cats) and therefore nearby waters are presumed to be more contaminated. On the other hand, these findings correspond with research showing that cats living in close proximity to humans are much less likely to be exposed to the T. gondii parasite than “solitary, feral domestic cats living in undeveloped landscapes” [53].

For more information, see Wildlife impacts of free-roaming cats: Estimates vs. evidence.




Are feral and stray cats responsible for toxoplasmosis in humans?


Toxoplasma gondii is a parasite found worldwide and capable of infecting virtually all warm-blooded mammals [41]. Cats — both domestic and wild felids (e.g., bobcats and mountain lions) — are the only known “definitive host,” as the parasite is able to reproduce sexually in these animals, forming egg-like spores (called oocysts) that are then shed in feces (typically for a one-week period) [41].

According to the Centers for Disease Control and Prevention, humans can become infected by consuming the undercooked meat of an infected animal or by the accidental ingestion of oocysts found in the environment (e.g., garden vegetables from contaminated soil) [42]. Infection rates in the United States have declined significantly over the last 30 years [43,44]. Although some small-scale studies have suggested a connection between cats, toxoplasmosis, and various cognitive and behavioral impairments, larger studies using more sophisticated analysis methods have found few if any such connections [ 45,46]. For more information, see Are stray or feral cats dangerous to humans and public health?





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