Month: February 2021

Cat Care

What is Trap-Neuter-Return (TNR)?

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Meredith Hemphill

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Encyclopaedia Felidae now has a Patreon! Go to www.patreon.com/EncyclopaediaFelidae if you want to help support this content!

Trap-neuter-return (TNR) is the process of humanely trapping community cats, sterilizing them, and then returning them to the location where they were caught. TNR is also sometimes called trap-neuter-release, trap-neuter-vaccinate-return (TNVR), and trap-neuter-return-monitor (TNRM).

Feral tabby cat in trap
Image by sandid from Pixabay

The accepted method of free-roaming cat control has been to take lethal measures. Animal control has used trap-and-kill methods for over a hundred years (1, 5, 9). In addition to being horrible, it clearly has not worked. Community cats didn’t disappear or even diminish as a result. This is due to the vacuum effect.

The vacuum effect happens when animals are removed from an environment, but the resources in the environment stay the same (3, 5). The remaining animals of the species will either breed until they reach the environment’s capacity again, or animals from elsewhere will migrate to the area, or both (1, 3, 5, 9, 11). In the end, no matter how many community cats animal control departments have euthanized, the population has always recovered. TNR was created as a solution that is humane and, while it takes time, ultimately effective.

How Does TNR Work?

The goal of TNR is to reduce community cat populations over time with the least possible harm to individual cats. Ideally, the cats ultimately benefit. Cats are trapped in box traps, which are designed to not cause injury, and taken to a veterinarian. How much care they receive at the clinic depends on who is doing the TNR, but at minimum the cat is sterilized. Rabies vaccines are pretty standard (1-3, 5, 9). A variety of other vaccinations are sometimes given as well. The cats are examined, and any health issues or injuries are treated.

During the spay/neuter surgery, veterinarians often mark community cats so that others can tell they are sterilized. This prevents the cats from the unnecessary stress of being captured and possibly operated on again (3, 6, 13). Eartipping is a common method of marking sterilized community cats. Eartipping means the vet removes the top quarter inch of a cat’s ear, usually the left ear, during the surgery (2, 3, 6). It doesn’t harm the cat, and it is clearly visible even from some distance. Alternatively, vets may put a small tattoo on the abdomen (12, 13) or a v-shaped notch in the side of the ear.

After cats recover from their surgery, they are returned to the site where they were captured so that they can resume their lives without making any more kittens. A caregiver may feed and keep an eye on the community cats, but they will continue to live mostly apart from humans and be happy to do so. Not all community cats are feral, however, so not every cat that is trapped in a TNR program will be returned. Kittens and friendly adults go to the clinic like the others, but then they are adopted out (1, 5, 9). Kittens should be left with their mothers until they are weaned if at all possible.

Advantages of TNR

…For the Cats

Sterilizing community cats has big benefits for their health. She-cats are spared the physical stress and dangers of repeated pregnancies (1, 5). Cats of both sexes have drastically lower risks of reproductive cancers (1, 3). Research has demonstrated that sterilized community cats gain weight and live longer lives, too (1, 3, 5). A study at the University of Florida found that 83% of the cats in TNR-managed colonies on campus had been in the colony for at least six years (1, 5, 7).

Eartipped brown tabby cat
Sterilized cats are eartipped to identify them – Image by Lmusser22 from Pixabay

Without the drive to mate, cats fight less and don’t wander as far, so they suffer fewer injuries (1, 3, 5). And while a single dose of a vaccine usually doesn’t last forever, the vaccination(s) cats receive through TNR are more protection than they would have otherwise had from infectious diseases (1).

…For the Community

Some people are really not happy to share their space with community cats. Fortunately, sterilized cats make better neighbors. They don’t yowl, fight, and spray nearly as much as intact cats do, and this can take care of a lot of peoples’ complaints with them (1, 3, 5, 8, 9, 11). Any problems that continue will dwindle over time as the community cat population shrinks.

Fewer community cats and fewer complaints about them leads to lower rates of shelter admission (1, 5, 8, 9-11, 13). San Jose, California Animal Control reported a decrease of 29.1% in their intake of cats and kittens after fours years of a citywide TNR program (6). Albuquerque, New Mexico saw a decrease of 43.5% in three years (6). This decreases the number of cats euthanized in shelters (1, 9-11). Many community cats that enter shelters are euthanized because they are not adoptable. About half of shelter workers who have to euthanize animals develop post-traumatic stress disorder (13). Not euthanizing healthy animals is better for everyone.

Fewer cats in the shelters also decreases their operating costs (1). But shelters are not the only ones that can save money as a result of TNR. The outdated catch-and-kill strategy hemorrhages taxpayer dollars to little or no effect (1, 5). As previously discussed, it just doesn’t work, but it does cost money. In the words of Mark Kumpf, former president of the National Animal Control Association, “The cost for picking up and simply euthanizing and disposing of animals is horrendous, in both the philosophical and the economic sense” (5).

The extent of the monetary cost depends on the animal control department. Similarly, how much can be saved depends on the TNR program and how it is run. In general, TNR programs appeal to volunteers and get progressively less labor-intensive over time (5). Any TNR program will save money that way.

Does It Really Work?

Research has demonstrated that TNR can, in fact, do all that is aims to, in a variety of communities at that. I’ve thrown some statistics at you already, but here’s a few more:

  • A TNR program that began in Newburyport, Massachuchetts in 1992 with about 300 cats essentially ended 17 years later when there were no cats left on the waterfront. The last cat, Zorro, died in December of 2009 at an estimated age of 16. No community cats have been seen at the waterfront since [as of interview date]. (10)
  • An 11-year study at the University of Florida observed community cats on campus. At the end of the study, the population had decreased by 66% and no new kittens had been seen since the fifth year. (7)
  • A Florida study conducted TNR for two years in one zip code, and then compared shelter intake from that zip code to the rest of the county. At the end of the study period, the shelters where there had not been any TNR had 3.5 times more cats admitted and 17.5 times more euthanized. (8).
  • A study of TNR efforts in Chicago, Illinois found that the average reduction in colony population was 54% over nine years. This was right after the city of Chicago changed its stance to support TNR. (11)
  • The University of New South Wales in Sydney, Australia, began a TNR campaign on campus in August, 2008. By September, 2017, the cat population had been reduced by 78%, and the 15 remaining cats were all sterilized. (12)
  • A survey of Australian TNR participants found that a median 69% of the cats in respondents’ colonies were sterilized. The median reduction in colony size was 31% over a median of 2.2 years of TNR. (13)

Criticisms of TNR

That was just a sampling of the studies supporting TNR. There have been a couple which studied a location where TNR was not successful, but the vast majority have given the method the thumbs-up. Many organizations champion TNR, including the American Society for the Protection of Animals, Humane Society of the United States, Association of Shelter Veterinarians, and American Association of Feline Practitioners. But TNR does have its opponents.

Community cats under tree
Image by Dimitris Vetsikas from Pixabay

Many of these opponents are conservationists. They are opposed to returning community cats to their territories because community cats hunt endangered birds and other wildlife (2, 4, 6). And that’s true, cats do hunt wildlife, and they are essentially an invasive species. As a domestic animal, they really have no natural habitat, although they may sometimes be considered naturalized in an environment. However, cats are far from the biggest threat to at-risk wildlife. Habitat loss is considered the worst offender by a wide margin (5, 6). Additionally, TNR is effective at reducing the population of community cats, so fewer birds and other prey animals will be hunted in future (5, 6).

Another concern is disease. Community cats can carry diseases that pet cats, humans, or other animals could catch, such as rabies and toxoplasmosis (2, 5, 6). This is certainly possible, but the Centers for Disease Control say that humans are very unlikely to get a disease from a cat (5, 6). The CDC reports only two cases of rabies transmitted from cat to human since 1960, and tells us that we would be more likely to get toxoplasmosis from eating raw meat or even gardening (5, 6). Pet cats or other animals are more at risk. However, TNR programs that vaccinate cats for common illnesses and treat them for any parasites they already have can go a long way toward reducing the disease burden in the community cat population.

Some claim that it is not humane to return community cats to their territory (2, 6). Certainly, life outdoors can be harsh. But what would be the alternative? Killing the cats can’t possibly be the more humane option unless they’re terminally ill or injured. Opponents of TNR do have some other suggestions.

A popular one is feeding bans (2, 4). A feeding ban is a law that makes it illegal to feed community cats. Nowhere that supported this solution spelled out why a feeding ban would be better, but I can only assume the idea is to drive cats away from people by withholding food, decrease the population by starving them, or both. Just because it’s illegal doesn’t mean people won’t feed cats, however (5). Even if they did, cats are resourceful. Some would starve, but many more would figure out another way to survive. If the goal is to protect wildlife, a feeding ban certainly wouldn’t help, because cats would only hunt a lot more wildlife and be driven to compete with wild predators.

Another suggestion is to criminalize abandoning cats or otherwise discourage people from abandoning their cats (2, 5). While I wish people didn’t abandon animals, they’re going to no matter what. They always have. People who argue that maintaining managed cat colonies through TNR encourages people to abandon their cats there are really missing the point (5). At any rate, even if no one ever abandoned a cat again, that leaves innumerable cats living on their own already that any action against future abandonment would no address.

There is no such thing as a perfect solution with a problem this complex. However, no one has found a better way than TNR for dealing with community cats humanely and efficiently. Even then, some programs work better than others. Everyone is learning as they go. TNR is still pretty new, but what a difference it has already made.

Ways to Get Involved

TNR can be done as an individual or with a group. Try checking with local animal shelters to see if they know of any groups doing TNR in your area. If you’re going it alone or with a few friends, make sure you’re completely prepared before you start. Alley Cat Allies, the organization that brought TNR to the United States, has excellent online resources, as do Best Friends Animal Society and Neighborhood Cats.

Step-by-Step Overview of TNR by Alley Cat Allies

Works Cited

  1. Alley Cat Allies. (2011). Why trap-neuter-return feral cats? The case for TNR. https://www.alleycat.org/resources/why-trap-neuter-return-feral-cats-the-case-for-tnr/
  2. American Bird Conservancy. (2015). Trap, neuter, release: The wrong solution to a tragic problem. https://abcbirds.org/wp-content/uploads/2015/05/TNR_the-wrong-solution2011.pdf
  3. American Society for the Protection of Animals. (n.d.). A closer look at community cats. https://www.aspca.org/animal-homelessness/shelter-intake-and-surrender/closer-look-community-cats
  4. Barrows, P. L. (2004). Professional, ethical, and legal dilemmas of trap-neuter-release. American Veterinary Medical Association, 225(9), 1365-1369. https://doi.org/10.2460/javma.2004.225.1365
  5. Best Friends Animal Society. (n.d.). Frequently asked questions about TNR. https://resources.bestfriends.org/article/frequently-asked-questions-about-tnr
  6. Best Friends Animal Society. (n.d.). TNR for stray cats: Meaning, history, statistics. https://resources.bestfriends.org/article/tnr-stray-cats-meaning-history-statistics
  7. Levy, J. K., Gale, D. W., and Gale, L. A. (2000). Evaluation of the effect of a long-term trap-neuter-return and adoption program on a free-roaming cat population. Journal of the American Veterinary Medical Association, 222(1), 42-46. https://doi.org/10.2460/javma.2003.222.42
  8. Levy, J. K., Isaza, N. M., and Scott, K. C. (2014). Effect of high-impact targeted trap-neuter-return and adoption of community cats on cat intake to a shelter. The Veterinary Journal, 201(3), 269-274. https://doi.org/10.1016/j.tvjl.2014.05.001
  9. Neighborhood Cats. (n.d.). What is TNR? Managing feral and stray cats. https://www.neighborhoodcats.org/how-to-tnr/getting-started/what-is-tnr
  10. Spehard, D. D. and Wolf, P. J. (2017). An examination of an iconic trap-neuter-return program: The Newburyport, Massachusetts case study. Animals, 7(11), 81. https://doi.org/10.3390/ani7110081
  11. Spehar, D. D. and Wolf, P. J. (2018). A case study in citizen science: The effectiveness of a trap-neuter-return program in a Chicago neighborhood. Animals, 8(1), 14. https://doi.org/10.3390/ani8010014
  12. Swarbrick, H. and Rand, J. (2018). Application of a protocol based on trap-neuter-return (TNR) to manage unowned urban cats on an Australian university campus. Animals, 8(5), 77. https://doi.org/10.3390/ani8050077
  13. Tan, K., Rand, J., and Morton, J. (2017). Trap-neuter-return activities in urban stray cat colonies in Australia. Animals, 7(6), 46. https://doi.org/10.3390/ani7060046

Published February 21, 2021

Breed Profiles

Snowshoe: Special Snowflakes of Cat Fancy

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Meredith Hemphill

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Encyclopaedia Felidae now has a Patreon! Go to www.patreon.com/EncyclopaediaFelidae if you want to help support this content!

Snowshoe cat on sofa
Image by TootSweetCarole from Pixabay

There’s a winter storm coming across half the United States this week, so now seemed like the perfect time to talk about the Snowshoe. No, not the things for your feet, although you might want some of those. I’m referring to an uncommon breed of cat whose paws look like they just took a stroll through the snow.

A Happy Accident

White paws cropped up occasionally as a “flaw” in Siamese cats for a long time (5). There is evidence of this is a Victorian photograph of a litter of purebred Siamese kittens in which one kitten has four white paws (2-4). The modern breed is fairly new, however. The first attempt to breed a color-point cat with white socks took place in the 1950s (2, 4). The nascent breed was called Silver Laces, but the breeding program was short-lived (2, 4). They got a second chance in the ’60s.

Dorothy Hinds-Daugherty, a Siamese breeder in Philadelphia, Pennsylvania, discovered three kittens with white paws in one of her cattery’s litters (3, 4, 6, 7, 9, 10). She thought the trait had potential. Hinds-Daugherty began by breeding the white-footed Siamese to a tuxedo Domestic Shorthair (3, 4, 6, 7, 10). This introduced white facial markings (3, 6, 10). She then bred those offspring back to Siamese cats to bring back the color-point pattern, which is recessive and must be inherited from both parents (7, 9). The resulting breed type was not quite like either parent breed. Hinds-Daugherty coined it the Snowshoe in honor of the white paws that started it all and applied (2, 3).

The Snowshoe faced an uphill battle, however. Some cat fanciers opposed the breed because they feared it might cause white markings to become a widespread problem in Siamese breeding stock (1). Snowshoes are also just difficult to breed. Their pattern relies on a combination of recessive traits and other genetic factors (2, 9). Breeders were discouraged by the inconsistency of the white markings (10). By 1977, only four Snowshoes were registered (2, 3). Just in time, breeders started to seriously take interest in Snowshoes. Nevertheless, the breed is still rare and difficulties remain in conforming these cats to type (2, 4, 9).

Breed Characteristics

Snowshoe cat full body
Championship Snowshoe – The International Cat Association

Straight to the Points

The hallmark of Snowshoes is their unique markings. They have a color-point pattern like their Siamese ancestors, meaning they have light-colored bodies with darker coloration on their legs, tails, ears, and faces (1-10). Although color-points can be any color and even come in patterns like tabby or tortoiseshell, Snowshoes are almost always seal (black/dark brown) or blue (gray) point (2-6, 9, 10). Lighter point colors make the Snowshoe’s white markings difficult to distinguish, and some may be difficult to breed (2, 4, 10).

Like all color-point cats, Snowshoes are born completely white and begin to develop their pattern with age. It may take up to two years for a Snowshoe’s pattern to come in (1)! Only once the color-points begin to appear and the body to darken will the other markings become apparent.

Snowshoes must have four white paws, but they can have other white markings as well (1-10). Snowshoes may or may not have white patches on their chins, chests, and stomachs (2, 4, 6-8). They can also have white on their faces. The breed standard prefers an inverted, symmetrical V in the center of the face (2-4, 9). Of course, the actual patterns of bicolor cats vary widely, which is just one of the difficulties in breeding Snowshoes.

The Snowshoe is not just a Siamese cat with white feet. Snowshoes have a blend of traits from both Siamese and Domestic Shorthairs. They are a medium-sized cat, moderately long like a Siamese but also muscular and athletic like a Domestic Shorthair (1-5, 7, 9, 10). The head is roughly shaped like an equilateral triangle (1-3, 9, 10). Inset in that face are the Siamese’s striking blue eyes (1-10). The eyes are considered “walnut shaped,” rounder than a Siamese’s almond eyes but narrower than a Domestic Shorthair’s (2-4, 9). They have short to medium fur with a smooth texture (4, 7, 9, 10).

Personality

Like everything else about them, the Snowshoe’s personality is a little bit Siamese, a little bit Domestic Shorthair. Like the Siamese, they are very “talkative” cats, although Snowshoes have a quieter voice with a melodic sound (4, 6-10). They’re intelligent, active cats who often enjoy learning tricks and games (3, 4, 8, 9). Snowshoes can be quite good at feline agility courses (4, 8)! Curiously, Snowshoes also enjoy playing and even sometimes swimming in water, a trait that doesn’t seem to come from either side of the family (3, 4, 6-9).

Snowshoe cat close-up
All Snowshoes have blue eyes – Image by TootSweetCarole from Pixabay

Snowshoes are highly social cats. They tend to bond most strongly to one person and want to spend a whole lot of time together (3, 4, 8-10). They’re usually pretty outgoing, however, and will be friendly to any trusted person–or pet. Snowshoes do well with children, dogs, and other cats, and in fact typically prefer to have some company when the humans are away (3, 4, 6, 8, 9).

Care and Keeping of Snowshoes

There are no known breed-associated health concerns with Snowshoes. Part of this is likely due to the newness of the breed. The Domestic Shorthair background may play a role as well. Domestic Shorthairs are just regular cats couched in fancy language, and they have the most genetic diversity in the cat world with occasional exceptions. Snowshoes can sometimes have kinked tails or crossed eyes like Siamese cats, but these idiosyncrasies don’t cause the cats any harm (4, 6, 9).

Because they are so social, Snowshoes can be prone to separation anxiety or simply boredom when left home alone (3, 6, 9). Fortunately, these cats’ ability to play well with other animals means that people who can’t be home all day, which is to say most of us, can have a Snowshoe as long as they have other pets to keep them company. Plenty of toys and places to climb is also recommended to keep these active cats out of trouble.

Snowshoes are really pretty low-maintenance as purebred cats go. Their short, single-layer coat requires only the most basic of grooming. No bathing required.

If you would like a Snowshoe of your own, Siamese cat rescues sometimes take them in, like Austin Siamese Rescue. SOS Cat Rescue and Rehoming, also in Texas, USA, rescues Siamese, Oriental Shorthairs, and Snowshoes. You can also check at your local shelter. Even purebred cats are surrendered and waiting for a forever home.

Fun Facts

  • Tardar Sauce, the world-famous Grumpy Cat, was a mixed-breed thought to have had Snowshoe in her gene pool, maybe. Her mother was a calico and her father was suspected to be a certain blue-and-white tabby but no one can say for sure. (3, 9)
  • A Snowshoe from California named Dusty earned the nickname Klepto Kitty due to his habit of stealing the neighbors’ belongings. Not just once or twice. Dusty was feature on The Late Show with David Letterman in February 2011, by which time he had stolen over 600 items! Dish towels, socks, gloves, and balls were frequent targets, but nothing–not even bikinis–was safe. (3, 8, 9)
  • A purebred Snowshoe kitten can cost between $750 and $1800. (3)
Dusty the Klepto Kitty

Works Cited

  1. Alderton, D. (1992). Cats: The visual guide to more than 250 types of cats from around the world. Dorling Kindersley Limited: London.
  2. American Cat Fanciers’ Association. (n.d.). Snowshoe breed synopsis. http://www.acfacat.com/snowshoe_synopsis.htm
  3. Baines, L. (2020, December 11). Introducing a puss in boots: The Snowshoe cat breed. CertaPet. https://breed.certapet.com/snowshoe-cat/
  4. Cattime. (n.d.). Snowshoe. TotallyPets. https://cattime.com/cat-breeds/snowshoe-cats#/slide/1
  5. Edwards, A. (2006). The ultimate encyclopedia of cat, cat breeds, and cat care. Hermes House: London.
  6. Johnstone, G. (2019, September 23). Snowshoe cat: Breed profile. The Spruce Pets. https://www.thesprucepets.com/snowshoe-cat-breed-profile-4769066
  7. Petfinder. (n.d.). Showshoe. https://www.petfinder.com/cat-breeds/snowshoe/
  8. Sorocco, E. (2019, January 10). 11 reasons to love the Snowshoe cat. Catster. Retrieved from https://www.catster.com/cats-101/facts-about-the-snowshoe-cat
  9. Taylor, C. (2020, September 4). Snowshoe cat. Daily Paws. https://www.dailypaws.com/cats-kittens/cat-breeds/snowshoe
  10. The International Cat Association. (2018, August 13). Snowshoe breed. https://tica.org/snowshoe-breeders?view=article&id=880:snowshoe-breed&catid=79

Published February 14, 2021

Behavior

Why do cats purr?

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Meredith Hemphill

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Encyclopaedia Felidae now has a Patreon! Go to www.patreon.com/EncyclopaediaFelidae if you want to help support this content!

Brown tabby cat in lap
Image by Hans Braxmeier from Pixabay

What could bring more joy than a purring kitty curled up in your lap? And there are so many different kinds of purrs. Some cats purr like a lawn mower engine, and some are so quiet you could barely hear them with your ear on their chest. Purring is a uniquely feline behavior. We associate it with happy kitties, but cats actually purr under a lot of different circumstances. This rather odd sound must serve a purpose besides being adorable. So why do cats purr?

Anatomy of the Purr

First things first: what even is purring? As someone who used to try it for myself as a child, I promise it doesn’t come naturally if you aren’t a cat. There was a lot of debate about how cats purred for a long time. One prominent theory was that the purring sound came from a change in the cat’s blood flow [1, 4, 6]. Now, biologists are generally agreed that cats purr using the muscles of their larynx and diaphragm [1, 3-5, 7]. By vibrating their larynx, which in turn vibrates their hyoid bone [5], a cat causes the air in their throat to vibrate as well, creating the sound we know as purring [1, 6].

Most vocalizations can only be made when exhaling. It just makes sense. You need air in your lungs to push through your larynx to talk, sing, laugh, etc. The same is true of other animals. However, cats can purr on the exhale and the inhale, which is what enables them to purr constantly [1-5, 7]. This is due to the continual vibration of the larynx as they breathe in and out through it [1].

Cats Purr to Communicate

Cats first start to purr by the time they are a week old [1, 2, 4]. The purring of her newborns may signal to a queen their location and wellbeing [1, 2, 4]. It is thought that each kitten has a unique purr their mother can recognize so that she can tell which of her babies is communicating with her [2].

Queens will also purr for their kittens [5, 6]. One reason may be to provide a tactile cue to help blind and deaf newborn kittens locate the milk supply [6]. Even though very young kittens can’t hear the purring yet, they can feel the vibrations because they are, ideally, never far away. Alternatively, the mother’s purring may disguise the soft mews of the kittens from the ears of predators [5]. Whatever the evolutionary reason, purring cements the bond between queen and kittens [5].

Some adult cats purr when feeding, possibly a throwback to that kittenhood behavior [1]. Cats may also purr to inform their person that they want their food, now please [1]! The purr of solicitation sounds different from the snuggly purr [1]. What’s the difference? It’s hard to say for sure. Our lack of knowledge about how cats communicate with each other makes it harder to understand the nuances of how they communicate with us.

One thing that’s certain is cats in the wild purr when they groom each other [1]. Grooming is an important part of a cat’s daily life and a positive social interaction between cats who have a bond. Perhaps this comes closest to the contended purring of a cat that is lying in a warm lap or being petted.

Mother cat and kittens in barn
Queens and their kittens purr to communicate – Image by Franz W. from Pixabay

Healing Vibrations

Cats don’t just purr for happy reasons. They sometimes purr when they’re stressed, scared, injured, or dying [1, 3-5, 7, 8]. Cats have sometimes been seen lying alongside another, injured cat, both purring [7]. This is called “purr therapy” because the purring is believed to be a way of comforting the injured cat [7]. In stressful situations, purring can serve as a method of self-soothing [7]. However, it may be an even more powerful tool than that.

Cats purr at a frequency of 20-150 Hertz [1, 3]. These low-frequency vibrations have demonstrated healing benefits [1, 3, 4, 7, 8]. 25 and 50 Hz frequencies promote bone growth and fracture healing [8]. 100 Hz has therapeutic use for pain, wound healing, swelling, and difficulty breathing [8]. It may seem far-fetched, but bones do respond to pressure by hardening [1, 7]. And there is a good evolutionary reason why cats might vibrate their way to good health.

Cats are ambush predators. This means they spend a lot of their time resting and waiting in-between hunts. Purring could have evolved as a low-energy way to stimulate their muscles and bones while stationary [3, 7]. Then their bones wouldn’t weaken or become brittle over time from lack of use [7]. Interestingly, researchers have proposed just such a fix for astronauts. Muscle atrophy and bone density loss are a big problem on long space missions where the lack of gravity prevents normal exercise. Vibrating foot plates have been suggested to stimulate astronauts’ bones and prevent them from losing density [7]. It seems the cats had that figured out a long time ago.

Do All Cats Purr?

Probably not, but it kind of depends upon how you define purring, apparently. Once upon a time in the early 1800s, biologists believed that cats could either roar or purr, but it was impossible to do both [7]. This is how cats came to be divided into the “big cats,” or subfamily Pantherinae, and the “small cats,” subfamily Felinae [6, 7]. Although most big cats are larger than most small cats, those names are actually a misnomer, since the smallest of the “big cats,” the clouded leopard, is smaller than the biggest of the small cats, the puma [7]. The basis of the division on roaring vs. purring is also probably inaccurate.

Two sleepy bobcats
Housecats aren’t the only ones that purr! – Image by Amber Stevens from Pixabay

The Pantherinae cats have a rope of tough, flexible cartilage where the Felinae have only the hyoid bone [5, 6]. This gives the larynx greater flexibility so that roaring is possible, although lions are the only ones to make regular use of this ability [5, 6]. Does this mean they can’t purr, though? These days, biologists tend to believe than most cats can purr, or at least something like it [3, 7]. Some call it a purr-like vocalization or a hum rather than a true purr [3, 4, 6].

Even granting that most cats can actually purr, some of the Pantherinae are usually believed to be exceptions: lions, leopards, jaguars, tigers, snow leopards, and clouded leopards [7]. But that may yet prove untrue. The anthropologist and animal behaviorist Elizabeth Marshall Thomas suggests that big cats may reserve purring for their cubs and that is why people think they don’t purr at all [6]. We simply aren’t around when they do.

Works Cited

  1. Dowling, S. (2018, July 25). The complicated truth about a cat’s purr. BBC Future. https://www.bbc.com/future/article/20180724-the-complicated-truth-about-a-cats-purr
  2. Edwards, A. (2006). The ultimate encyclopedia of cat, cat breeds, and cat care. Hermes House: London.
  3. Lyons, L. A. (2006, April 3). Why do cats purr? Scientific American. https://www.scientificamerican.com/article/why-do-cats-purr/
  4. Science Reference Section. (2019, November 19). Why and how do cats purr? Library of Congress. https://www.loc.gov/everyday-mysteries/item/why-and-how-do-cats-purr/
  5. Stewart, D. (1995, April 1). Do lions purr? And why are there no green mammals? The National Wildlife Federation. https://www.nwf.org/Magazines/National-Wildlife/1995/Questions-and-Answers-About-Wildlife
  6. Thomas, E. M. (1994). The tribe of tiger: Cats and their culture. Simon & Schuster: New York.
  7. Venton, D. (2015, May 8). Why do cats purr? It’s not just because they’re happy. Wired. https://www.wired.com/2015/05/why-do-cats-purr/
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Published February 7, 2021

Updated June 20, 2022