I suppose if you don’t believe in ghosts, then the answer to the question “can cats see ghosts?” is “no, ghosts don’t exist.” But that’s boring. We’re here for some spooky season fun! If you have seen your cat staring intently at nothing and wondered what they see that you don’t, this article is for you.
Cats’ Remarkable Senses
Do Cats See Ghosts?
Cats certainly can see and sense things that we humans cannot. Cats’ eyes are adapted to see very well in low light because they are naturally most active at dawn and dusk, when most of their prey is awake [1-5]. Their night vision is six times better than ours because they have so many more light-sensing rod cells in their retinas [3, 5]. Cats also have a reflective layer of tissue behind their retinas called the tapetum lucidum which helps them maximize light absorption [4, 5].
Not only can cats see with just the tiniest amount of light, but they can see wavelengths of light that are completely invisible to us [2-6]! Humans see a lot of colors and a lot of detail, but we cannot see ultraviolet light [5, 6]. However, cats and many other animals can [6]. The list includes dogs which many people also believe can see ghosts [2]. Scientists don’t always know why some animals see the wavelengths that they do, and that goes for cats [6]. Rodents use their ultraviolet vision to follow urine trails [6], so perhaps cats benefit from following their trails, too? Or maybe the extra light simply adds another boost to their dark vision. If ghosts are visible in the ultraviolet spectrum, though, then cats do see ghosts.
Do Cats Hear Ghosts?
Cats can also hear much better than we can. The better to catch little, squeaky mice, my dear. Their hearing is about six times sharper than ours [1, 2]. That includes being able to hear sounds 1.5 octaves higher in pitch [4, 5]. Many people believe that ghosts speak outside our hearing range, but perhaps our cats can pick up on them. Think about that the next time your kitty’s ears perk up, and you didn’t hear anything.
Ghosts in the ceiling?
When I first adopted my cat Joon, I lived in a top-floor apartment with a roommate and her cat. The whole time I lived in that apartment, I would hear what sounded like footsteps or furniture being moved around in the apartment above us–except, of course, there was no apartment above us. Just the roof. I thought maybe my ears were playing tricks on me and the sounds were actually coming through the walls, not the ceiling, until I got Joon. In the evenings, when the noises started, she would stare up at the ceiling for the longest time and sometimes sit up on her haunches like she wanted to swat at whatever was up there. I never did figure out if we had ceiling ghosts or people living in the walls or what, but it was very creepy, that’s for sure. Since I moved out of that apartment, Joon has never shown that much interest in the ceiling. Unless there’s a bug on it, of course.
Do Cats Feel Ghosts?
Perhaps the most remarkable of the feline senses is their ability to feel tiny vibrations and changes in the air. A cat’s whiskers detect changes in temperature and air current around them [2, 4, 5]. This helps them navigate small spaces, know what’s around them in the dark, and feel oncoming danger without having to turn around [4, 5]. Perhaps it also helps cats feel any spirits walking by–or through–them.
“That’s one of the things that truly makes animals better than us, smarter than us. Cats aren’t burdened by a lifetime of belief like us. Cats are worried about what could or couldn’t be. They’re worried about what is.”
It’s hard to figure out what your cat is looking at if you can’t see it. Maybe they hear a mouse in the wall or see a tiny bug that you just can’t perceive with your human senses. Maybe they do see a ghost! If your cat seems to be stressed by something you can’t see, however, do your best to investigate. Make sure a medical problem isn’t the culprit. Cats can behave very strangely when they’re in pain and don’t understand why. Also, check for any sources of stress in the physical realm, like a neighborhood cat whose presence outside is putting your pet on edge. If you’ve ruled out any material causes, and your cat still seems upset by a presence in the home, then it might be time to call some ghost busters. On the other hand, if your cat isn’t bothered by that thing they stare at in the corner, only curious, maybe don’t worry about it too much.
A couple days ago, my friend texted me while they were looking at a black panther exhibit at the art museum and asked me what kind of cat black panthers actually are. I had to break it to them–and now to you–that there really isn’t any such thing as a black panther. The name “black panther” is applied to individuals of several species of wild cat which are all black due to a rare genetic condition called melanism. Most black panthers are actually leopards or jaguars, both of which are normally yellow with black spots [9].
What is melanism?
Many cats come in black [4]
Melanism is a rare genetic mutation that causes animals to have black skin and fur/feathers/whatever when members of their species typically do not [1, 3, 4, 7, 9]. The mutation causes the affected animals to produce an excess of the dark color pigment melanin [1, 2, 7]. Lots of animals can be melanistic, including pigs, cows, mice, butterflies, snakes, lizards, and snails [2, 4, 7]. Melanism is more common in felids than most taxa, however [1-3, 7]. 15 of the 40 species in the genus Felidae are known to exhibit melanism [4].
Melanistic cats have black fur all over their bodies but may still have some of the patterning or their “normal,” or wild-type, brethren. For example, black leopards still have rosettes which are even darker black [7, 9], and some melanistic Asian golden cats have a white mark on the underside of their tails [4].
Melanism mutations have cropped up at least eight separate times in the cat family tree [3]. These different mutations don’t all work exactly the same way. Mutations in the ASIP gene are recessive, meaning that a cat has to inherit the mutation from both parents to be black [2, 7]. The ASIP protein normally inhibits eumelanin (dark pigment) production, and these mutations make the ASIP protein non-functional [2, 7]. Leopards and Asian golden cats inherit melanism as a recessive ASIP mutation [2, 3, 6-9].
Mutations in the MC1R gene are dominant, so a cat can inherit either one or two copies of the mutation to be melanistic [2, 7]. MC1R promotes the production of eumelanin, and the mutations increase its activity [2, 7]. Jaguars and jaguarundis inherit melanism as a dominant MC1R mutation [2, 9].
How many black panthers are there?
In general, the rate of melanism in the felid species that have it is thought to be around 10% [3, 9]. However, the actual percentage varies widely depending upon the species and specific population [1, 3, 4, 8]. Leopards range throughout Africa, up through Asia, and as far north as Siberia. In Africa, they are almost never seen in their black panther form, but in Malaysia, the exact opposite is true–almost all leopards are black [3, 4, 7-9]. Southeast Asia in general has about half melanistic, half wild-type leopards [3]. Servals are more likely to exhibit melanism in the East African highlands and the Tsavo ecosystem of southeast Kenya [1]. While most species have fewer melanistic cats than wild-type, 80% of jaguarundis are melanistic [2, 4].
Melanistic (A) and wild-type (B) tigrinas [4]
It’s difficult to get an accurate count of how many wild cats there are in the world to begin with, due to their stealth and dwindling habitats. Counting black cats has its own particular challenges. Sometimes reports of a “black panther” are ambiguous or a case of mistaken identity [5]. There is still debate about whether or not melanistic cougars actually exist for that reason [5]. Because melanistic wild cats are rare in most environments, people are more likely to take notice of them and tell somebody if they see one, possibly inflating their numbers [1].
Why are only some big cats melanistic?
The evolution of melanism in felids is still up for discussion among biologists. The most prominent theory is that melanism is so common among cat species because it helps camouflage them in dark, forested places [3, 8]. As ambush predators–and sometimes prey for bigger animals–most cats specialize in stealth, so camouflage is important. This would explain why melanism is more common in cats in jungle habitats and very rare in open grasslands where a black cat would really stand out [3, 8].
Researchers have found some other possible benefits to being a black panther, too. Dark coloration may aid in temperature control in high-altitude or cool, moist forest environments [1, 9]. Research in dark-colored birds has shown that they are resistant to feather-degrading bacteria [3], so there is a possibility that melanistic felids have some additional immunity to disease [3, 8].
There may be some downsides to that glossy black coat, however, even in favorable habitats. Black leopard pairs have smaller litter sizes [6], although the melanism mutation itself appears to have no ill effects [7]. Graipel et al. found evidence that melanistic cats in some species may have a disadvantage in communicating with their peers because the lack the white spots behind their ears or on their tails characteristic of their species [4]. Wild cats use these spots to send signals to each other at short distances, silently, without alerting prey or predators [4]. This is more important for some species than others, depending upon their habitat and whether they are more active when it’s light or dark [4]. Some felids don’t have these spots at all [4]. So it’s more advantageous to dress in black for some cats than for others.
Miniature black panthers
One of the felid species that exhibits melanism is the domestic cat, Felis catus [7]. That’s right, you might have a black panther of your very own! Not all black housecats are melanistic, however, because coat color genetics are complicated. Melanistic cats will be solid black, absolutely no white hairs, and their skin will be black as well. Also, fun fact: melanistic kittens often have “ghost” tabby stripes that typically fade with time, like the black leopard’s shadowy spots [7].
Eizirik, E., Yuhki, N., Johnson, W. E., Menotti-Raymond, M., et al. (2003). Molecular genetics and evolution of melanism in the cat family. Current Biology, 13(5), 448-453. https://doi.org/10.1016/S0960-9822(03)00128-3
da Silva, L. G., Kawanishi, K., Henschel, P., Kittle, A., et al. (2017). Mapping black panthers: Macroecological modeling of melanism in leopards (Panthera pardus). PLoS One, 12(4), e0170378. doi:10.1371/journal.pone.0170378
Graipel, M. E., Bogoni, J. A., Giehl, E. L. H., Cerezer, F. O., et al. (2019). Melanism evolution in the cat family is influenced by intraspecific communication under low visibility. PLoS One, 14(12), e0226136. https://doi.org/10.1371/journal.pone.0226136
Schneider, A., David, V. A., Johnson, W. E., O’Brien, S. J., et al. (2012). How the leopard hides its spots: ASIP mutations and melanism in wild cats. PLoS One, 7(12), e50386. doi:10.1371/journal.pone.0050386
Cat scratch fever isn’t just a song by Ted Nugent. Being scratched by a cat is just one of the hazards of having one, but seemingly minor nicks can lead to nasty infections. It’s important to take good care of any cat-induced injuries.
Not only are cats’ claws sharp, but they can carry bacteria [1-5]. So, step one after getting scratched by a cat is to clean the wound [1-5]. Flush the wound with running water [2, 3] and then wash it with mild soap [1-5]. If it’s a serious enough scratch that it’s still bleeding after that, apply pressure with a clean cloth or bandage to stop the bleeding [2, 3]. Then apply a topical antibiotic (like Neosporin) and cover with a sterile bandage [2, 3].
For most cat scratches, that’s all the attention the injury needs. If it doesn’t break the skin, all you have to do is clean any bacteria off, and you’re done. But sometimes, a scratch can get infected and even make you quite sick, so keep an eye on the wound and be vigilant for any symptoms of the infections below [1-5].
Cat Scratch Fever
Cat scratch fever, also called cat scratch disease or CSD, is an infection caused by the bacterium Bartonella henselae [1-3, 5]. Cats become infected with B. henselae from fleas or by fighting with other infected cats [1-5]. Up to 30% of cats carry this bacterium in their blood [1]! But cats rarely become sick from it [1, 3, 5]. When an infected cat scratches or bites a human and breaks the skin, or licks a human’s open wound, then the B. henselae bacteria get into that person’s bloodstream, and that’s what causes CSD [1-5].
Symptoms typically start between 3 days and 2 weeks after the cat scratch or bite [1, 3, 5]. The injury may become red, swollen, warm, and painful; develop lesions; and exhibit pus [1, 3-5]. Later, lymph nodes near the injury may swell and get sore [1, 3-5]. Other symptoms that may develop include fever, headache, loss of appetite, fatigue, and joint pain, somewhat like the flu [1, 3-5].
Usually, CSD is not serious and will resolve on its own or with antibiotics [1-5]. However, in rare cases it can cause serious problems with the brain, eyes, heart, or other organs and require intensive treatment [1-5]. Children from ages 5-14 and people with weak immune systems are most likely to have these complications [1, 4, 5]. If you notice any signs or symptoms of CSD after being scratched by a cat, see a medical professional right away, just to be safe [1-5].
Other Infections You Can Get from Being Scratched by a Cat
Other pathogens can be present on a cats claws and be introduced under your skin by a scratch. One example is Staphylococcus aureus, a common bacterium on the skin of humans and other animals that can cause several types of infections when introduced inside the body [2]. Another culprit is Campylobacter [2]. Campylobacter is typically spread through cat feces, but cats bury their poop with their paws, so the bacteria can be on their claws, too [2]. A Campylobacter infection can cause fever, stomach cramps, nausea, and diarrhea [2]. Pasturella bacteria are spread by cat bites and scratches, too [2]. The bacteria attack the joints and tendons, causing pain and swelling, and symptoms can appear within a few hours [2].
Quick Tips to Prevent Scratches
Anything can be a toy, and toys will be destroyed – Image by Birgit from Pixabay
If you have cats, you’re probably going to get scratched sooner or later. There are a few things you can do to make it less likely, however. First of all, DO NOT play with your cat using your hands [3]! Only use toys, preferably ones that keep your hands far away from the action. If you use your hand like a toy, your cat will treat it like a toy. And you’ve seen how they treat their toys.
Keeping your cats nails trimmed can help prevent scratches as well, especially accidental ones [3]. Many cats don’t care for this, but they can usually be accustomed to it over time. You can have a groomer do it for you, but keep in mind that your cat will associate the groomer with the claw trimming. They may learn to resist their grooming appointments like they do their vet visits. There are advantages to doing it yourself at home and giving them their favorite treat when you’re done.
Sources
Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases. (2023, June 13). Cat scratch disease (Bartonella henselae infection). https://www.cdc.gov/healthypets/diseases/cat-scratch.html
Last month, an article was published in Nature Communications by a team of scientists from the Cincinnati Zoo and Botanical Garden, the Horae Gene Therapy Center, and Massachusetts General Hospital [7-9]. They tested a gene therapy injection as an alternative to spaying and neutering for cat birth control, and the results are exciting.
Why do we need cat birth control?
80% of the estimated 600 million domestic cats in the world are strays or feral [4, 9]. Cat overpopulation leads to more disease and greater loss of birds and other small animals from predation [2-6]. Animal shelters become overrun with homeless kittens and cats, and many are ultimately killed. Cats reproduce very quickly, so it doesn’t take long for a few to become a serious overpopulation issue. The only method of sterilization currently available is spay/neuter surgery. It is effective and permanent, but there are drawbacks.
Surgical sterilization has to be performed by a veterinarian at a surgical clinic [2]. It’s an invasive procedure for females, and both sexes are supposed to have a recovery period, including medication [2]. It’s also expensive [2, 6]. Those resources are in short supply, even more so in developing countries [1, 2, 6]. Thus, there has been interest in non-surgical cat contraception for years. Previous attempts have included vaccines targeting the pituitary gland, toxins targeting reproductive cells, and RNA-silencing drugs to shut down the genetic mechanism of conception [1, 3, 5]. All were either ineffective or unsafe [3, 5].
The Alliance for Contraception in Cats and Dogs (ACC&D) was founded in 2000 with the goal of finding a one-time, permanent, non-surgical contraceptive that would help to curb the overpopulation of homeless cats and dogs [1, 5]. ACC&D wasn’t involved in this study, but ACC&D President Joyce Briggs said, “This research is a huge leap—we’re really excited about it” [1, 5]. She also noted that the lead author, Dr. Lindsey Vansandt, is someone they have worked with before on a contraceptive vaccine called GonaCon [1].
The organization that provided the primary funding for the Vansandt research team has a similar goal. The Michelson Found Animals Foundation was founded in 2009 by inventor Gary Michelson [1, 2, 5]. Its goal is also a single-use, permanent, non-surgical dog and cat birth control, although specifically as a marketable product [1, 2]. Toward this end, the Michelson Found Animals Foundation created the Michelson Prize, $50 million (USD) in research funding plus $25 million if successful [1, 2, 5, 7]. So far, they have given out 41 grants [1, 5].
David Grimm, a journalist for Science, explained that it can be very difficult to get funding for this kind of research; most of the money goes toward studying the human body. So the Michelson Prize grants have been a huge boost to searching for a better companion animal contraceptive. [2]
The Experiment
Dr. David Pepin didn’t have his eyes on the Michelson Prize at first, however. Pepin was looking for ways to help women with ovarian cancer preserve their fertility [6-8]. He was studying anti-Müllerian hormone (AMH), sometimes called Müllerian inhibiting hormone (MIS), which made by the ovarian follicles of female mammals [1, 2, 4-8]. An ovarian follicle is a layer of cells around an egg that nourish the egg as it grows and matures.
Pepin was trying to learn more about what AMH does, so he injected an extra copy of the AMH gene into female mice [2, 4, 5]. This technique, sometimes called gene therapy, does not change the native DNA. It adds new, free-floating pieces of DNA into the cells, complete with all the information the cells need to read the “instructions” on the new piece of DNA. Gene therapy has been used to treat genetic diseases in humans, hence the name, but in this case Pepin was using the same procedure for research purposes to see how the mice would respond to high levels of AMH. He was surprised when the mice’s ovaries shrank, stopped producing eggs, and became infertile [1, 2, 4-6].
“We thought, well, this is a very interesting tool, but what can we use it for?” Pepin said [4]. He decided to submit an application for a Michelson Prize grant, and Bill Swanson, Director of Animal Research at the Cincinnati Zoo, happened to review it [1, 2, 4, 5]. Swanson had actually been working on an opposite project, trying to increase breeding in captive big cats [2, 5]. However, the Cincinnati Zoo maintains a research colony of domestic cats, and Swanson thought Pepin’s proposal was a great idea, so a partnership was struck [2, 4, 5].
Experimental design – From Vansandt et al. 2023
The study was small, with three groups of only three she-cats each [3-5, 7, 9]. The nine cats were all named after former first ladies: Michelle, Betty, Abigail, Nancy, Dolly, Barbara, Rosalyn, Jacque and Mary [4]. The domestic cat gene for AMH was constructed into a piece of DNA that the cats’ cells could read, and then that piece of DNA, named fcMISv2, was taken up by the harmless AAV9 virus [9]. Viruses are used in gene therapy because they naturally have the ability to insert genetic material into cells. Three cats served as a control group and were injected in the thigh muscle with AAV9 viruses that were empty, no DNA to inject [3, 7, 9]. Three cats were injected with a lower dose of viruses carrying the gene, and the other three received a higher dose [3, 7-9].
The experimental cats’ muscle cells successfully incorporated the fcMISv2 DNA and began to make AMH [9]. According to Pepin, “A single injection of the gene therapy vector causes the cat’s muscles to produce AMH, which is normally only produced in the ovaries, and raises the overall level of AMH about 100 times higher than normal” [7, 8]. Although their AMH levels increased, only progesterone decreased in response [5, 9]. Their other hormone levels remained the same, their hormone cycles were unaffected, and they showed no signs of adverse side effects [2, 3, 5, 7-9].
During two mating trials, two different toms were each introduced to the nine she-cats for four months at a time [3, 5, 7, 9]. All of the cats in the control group mated, became pregnant, and gave birth to kittens [3, 5, 7-9]. Only two of the cats who received gene therapy even allowed the toms to mate, and none of them ever became pregnant or had kittens [3, 5-9]. At the end of the two-year study, they were maintaining steady, elevated AMH levels, and the scientists are cautiously optimistic that this method may be a permanent contraceptive [5, 7-9].
What happens next?
It remains unclear exactly how AMH functions as kitty birth control [1, 2, 5, 9]. The researchers believe that the elevated levels of AMH prevent she-cats’ follicles from developing and thereby prevent ovulation [2-5, 9]. However, more research is needed to understand exactly how AMH works, and to answer lingering questions.
For instance, is this sterilization truly permanent [1, 2, 6]? The scientists who authored the study believe it is, but they only tested those cats for two years, so no one can say for sure yet that it doesn’t eventually wear off. Are there any negative side effects that they didn’t catch in such a small study [6]? Could AMH work for dogs, too [1, 2, 5, 6]? That is an important goal of this kind of research, not to mention a requirement to win the Michelson Prize [1, 5]. There are also concerns about cost, as that is often what prevents people from spaying and neutering cats now [1, 2]. If a new AMH shot will cost as much or more than surgically sterilizing cats, the convenience of the one-dose injection won’t really matter [1, 2].
Pepin, Swanson, and the Michelson Foundation are already in talks with the Food and Drug Administration about a larger trial and the possibility of bringing an AMH drug to market [2, 5, 6], so keep your ear to the ground. In the meantime, GonaCon, the cat birth control vaccine that study author Lindsey Vansandt worked on with ACC&D, has shown promise as well and may actually be closer to becoming available [1]. Either way, this area of study appears to be accelerating, and there may be more exciting news to come in the next few years.
Effective feline contraception means fewer homeless kittens – Image by Sommer from Pixabay
As for the cats from the study, they were all put up for adoption after the research concluded [4]. This is something the Cincinnati Zoo does with their research participants–Bill Swanson already has three cats he adopted from previous studies [4]. I couldn’t find out if all nine have been adopted yet, so if you live in the Cincinnati area and are looking for a new feline friend, email [email protected]. The cats’ new owners are asked to bring them back to the zoo for a yearly check-up to monitor their hormone levels and make sure there haven’t been any side effects [4].
Vansandt, L. M., Meinsohn, M., Godin, P., Nagykery, N., et al. (2023). Durable contraception in the female domestic cat using viral-vectored delivery of a feline anti-Müllerian hormone transgene. Nature Communications, 14, 3140. https://doi.org/10.1038/s41467-023-38721-0
The short answer is, no, cats don’t always land on their feet. But they do have a remarkable knack for it. They start to develop the uncanny trait by the time they’re three-week-old kittens [7]! And it’s not just domestic cats–wild felines, even big cats like tigers and leopards, can do it, too [3]. Humans have been mystified by this ability for centuries, at least [4]. Most of us aren’t that graceful. Neither are our dogs, horses, guinea pigs, and other pets. So how do our cats land on their feet?
Born to Fall
Cats and many other felines are arboreal animals [3, 6]. This means that in the wild, they spend most of their time in trees. Arboreal animals obviously have to be good at climbing, but they also have to be good at falling [6]. It’s an inevitable danger of life in the trees. So cats have several adaptations to help them fall gracefully. Cats have a high ratio of surface area to body weight, so when they fall, they create a lot of drag and fall more slowly than many other animals [3, 6]. A falling cat instinctively spreads out their legs like a parachute to slow their descent even more [2, 6, 8]. Cats also have relatively long, muscular legs and springy joints that act as shock absorbers [3, 6]. But, of course, that only works when cats land on their feet. This brings us to a particularly complex adaptation, the aerial righting reflex.
All creatures that live in trees have an aerial righting reflex [6]. The aerial righting reflex describes the ability of these animals to know which way is down while falling and to reorient their bodies to land upright [3-6]. Cats can even execute this maneuver while blindfolded [4]. Physicists and biologists conducted experiments by dropping cats (and sometimes other animals) under various circumstances for centuries, trying to understand how they did it [4]. Then in 1894, the French physiologist Étienne-Jules Marey used an early slow-motion photography technique to photograph a falling cat, finally revealing the series of precise twisting motions that cats use to turn themselves right-way-up [4, 5].
DO NOT TRY THIS AT HOME. My mother has admitted to trying the cat-dropping experiment on the family cat when she and my uncle were kids, and during my research I stumbled upon many online videos of people doing the same. I’m sure countless cats have survived such “tests” without injury, but it’s not worth the risk that something might go wrong this time, and your cat gets hurt.
For the aerial righting reflex, cats rely on the semicircular canals deep inside their ears [1, 4, 8]. These tiny, fluid-filled tubes are what many animals use to sense the pull of gravity and to maintain their balance, including humans. If a cat’s semicircular canals are damaged, they can no longer right themselves in the air, even if they can see their surroundings [4]. Using the information from these inner ear structures, the cat’s brain quickly establishes which way is up vs. down. Then they employ some physics.
Some Physics
The angular momentum of a spinning object is a function of its mass, the distribution of that mass, and its rotation rate. If no outside force acted upon the object, the angular momentum wouldn’t change. This is why a figure skater spins faster when they pull their arms tight against their body. They are decreasing the distribution of their mass, but their mass itself can’t change, so their rotation speed must increase. This is the principle behind how cats flip themselves around in midair. [4, 5]
The first step of the aerial righting reflex, then, is for a cat to arch their back, which for physics purposes separates their body into two rotating halves. Then they rotate their head to get their front half spinning and extend their hind legs. Tucking in their front legs causes their front half to rotate quickly. To conserve their angular momentum, their back half will start to rotate in the opposite direction around its axis, but with their hind legs stuck out, it rotates more slowly. Extending the front legs stops the rotation of that half of their body. The back legs catch up, and after about 1.5 seconds, kitty has turned all the way around to land on her four paws. [4, 5]
If you find that explanation hard to follow…me too. I had to read it about ten times and look at the diagrams in chapter seven of Falling Felines and Fundamental Physics to figure it out [4]. Looking at Marey’s photograph series and watching videos like the one below helped, too.
The righting reflex in slow motion
High Rise Syndrome
On the subject of cats mostly landing on their feet, I want to tell you about high rise syndrome. With the literal rise of urban life building taller and taller apartment complexes, cats and other pets sometimes fall off of balconies and out of windows [2, 3, 6, 8]. Cats have great survival skills, but nothing in nature equipped them to think about clear glass or twenty-story buildings [2]. They’re instincts evolved to climbs trees, not concrete jungles. Unfortunately, because cats are particularly inclined to climb and pounce at birds, they are also especially likely to experience these falls [2, 8]. The term high rise syndrome can refer either to the phenomenon of cats falling from tall buildings [8] or to veterinarians’ and researchers’ curious observation that cats tend to have better outcomes when falling from higher stories than lower ones [2].
The research isn’t entirely consistent, but there are indications beyond the anecdotal evidence of veterinarians that it might be true, at least sometimes [8]. The most dangerous falls are generally said to be between the second and sixth stories (20-60 ft or 6-18 m). A fall from the first story is hardly even a fall, especially for a cat. But why would they be in less danger about the sixth story? Experts believe that when cats fall from just a few stories, they don’t have enough time to complete the aerial righting reflex, so they may land in awkward positions that cause greater injury [2].
Of course, there is a height at which the benefit of the reflex wouldn’t be enough, but for obvious reasons no one has experimented to find out exactly what that height is. We do know that cats can survive thirty-story falls, often with severe injuries [2]. However, a 1987 study in New York City of cats brought to a veterinarian after falls from high-rises found that not only did 90% survive, but one cat that fell thirty-two stories suffered only a chipped tooth and a collapsed lung [6]. A study published in 2004 which looked at 119 cats that fell from apartment buildings and were brought to a clinic in Zagreb, Croatia, found that the most common injury was a broken leg [8].
Preventing Your Cat from Falling
The researchers in the 2004 study also found that younger cats fell more often which makes sense, because kittens and young cats are more energetic, more curious, and less aware of the world’s dangers [8]. They reported that 65% of high-rise falls happened in the warmest months, from April-September [8]. Other research has shown the same thing: the warm spring/summer season leads to more incidents of high rise syndrome [2, 8]. This happens because people tend to open windows and balcony doors when it’s warm out [2, 8]. So either keep your doors and windows closed or put screens on them, especially if your cat is a youngster [2, 8]! And always keep an eye on kitty if you let them go out on the balcony. Outside time is great, but that’s not a safe place for a cat to be unsupervised.
In 2014, Gizmo survived a 12-story fall from his Manhattan apartment. He has a lot to say about it.
Works Cited
Alderton, D. (1992). Cats: The visual guide to more than 250 types of cats from around the world. Dorling Kindersley Ltd. London.
Becker, M. and Spadafori, G. (2006). Do cats always land on their feet? 101 of the most perplexing questions answered about feline unfathomables, medical mysteries & befuddling behaviors. Health Communications, Inc. Deerfield Beach, FL.
Sechzera, J. A., Folsteina, S. E., Geigera, E. H., Mervisa, R. F., et al. (1984). Development and maturation of postural reflexes in normal kittens. Experimental Neurology, 86(3), 493–505. doi:10.1016/0014-4886(84)90084-0
Vnuk, D., Pirkić, B., Matičić, D., Radišić, B., et al. (2004). Feline high-rise syndrome: 119 cases (1998–2001). Journal of Feline Medicine and Surgery, 6(5), 305–312. doi:10.1016/j.jfms.2003.07.001
Shoutout to Dad for suggesting calicivirus as a topic.
Upper respiratory infections are common in cats. Often called cat flu, these infections are a lot like the colds and flus that humans get in the winter. Cat flu is highly contagious, but not very serious for most healthy adult cats. It can be dangerous for young kittens, seniors, and cats with chronic illnesses or weak immune systems. Like human colds, cat flu can be caused by more than one virus, but one of the most common culprits is feline calicivirus.
What is Feline Calicivirus?
A calicivirus showing the characteristic chalice shapes on the surface – Photo by Marian C. Horzinek [2]
Feline calicivirus (FCV) is part of the Caliciviridae family of viruses [1, 2]. There are viruses from this family that afflict a wide range of vertebrate animals, including humans [1, 2]. Norovirus is a member of the Caliciviridae, as are some diseases of rabbits [1, 2]. The name calicivirus comes from the Greek work “calyx,” meaning “cup” or “goblet” [2]. This refers to the cup-shaped depressions on the surface of the hexagonal or star-shaped virus particles [2].
Feline calicivirus is specific to cats, both housecats and wild species [1, 2]. It is a single-stranded mRNA virus, a type which is particularly prone to mutation [2]. This has led to there being many different strains of FCV around the world.
How Are Cats Infected with Calicivirus?
FCV spreads most often in environments where a large number of cats live in close proximity to each other, such as boarding kennels, pet stores, shelters, breeding facilities, and dense feral colonies [1-5]. The risk begins to increase dramatically when as few as four cats are in close proximity [2]. In groups of fewer than four healthy cats, the infection rate is 2.5%, but groups of four or more healthy cats have an infection rate of 32% [2]! In colonies and shelters, the rate can range from 50-90% [2].
The virus is spread through direct contact with body fluids from an infected cat, primarily saliva and eye and nose secretions [1-5]. Blood, urine, and feces can also spread the virus, as can aerosolized droplets from sneezes [1-5]. This means sharing things like food bowls, water bowls, litterboxes, and bedding can spread FCV [1-3]. So can just sharing an environment, or human caretakers can accidentally spread the virus around by getting it on their hands or clothes [1-3]. Most infected cats shed virus for 2-3 weeks, but some become carriers and continue to spread FCV for months or years [1, 2].
Symptoms of Feline Calicivirus
The typical presentation of FCV is an upper respiratory infection [1-5]. The virus attacks the inside of the mouth and the lungs [1, 2]. The symptoms include the usual upper respiratory signs like sneezing, stuffy/runny nose, runny eyes, and sleepiness [1-3]. However, FCV may also cause ulcers inside the mouth, which may in turn lead to drooling and refusal to eat due to oral pain [1-5]. Occasionally vulnerable cats, usually young kittens, will develop pneumonia [2, 3]. It is rarely fatal, however, and most cats will recover in a week or so, although severe cases may take up to six weeks [1].
Some cats who become infected with feline calicivirus go on to develop chronic gingivitis [1-5]. Researches do not yet know why this happens, or why it only happens to certain cats [2]. If your cat has recently recovered from cat flu and is still having problems with their mouth, this is probably something to talk to your veterinarian about.
Limping Syndrome
FCV can sometimes attack the joints and result in a strange–and upsetting–manifestation known as limping syndrome [1-5]. It mostly occurs in kittens [3, 4], and it can look very scary. Affected kittens develop a fever as well as pain, stiffness, and lameness in their joints, but which limb(s) are affected may change over time [2-4]. Sometimes limping syndrome occurs as a side effect of an FCV vaccination, not from an infection [2, 3, 5]. Although it is painful, limping syndrome only lasts 2-3 days and usually clears up on its own [2-4]. However, during that time, your veterinarian may be able to prescribe anti-inflammatory and/or pain medication to make your kitten more comfortable [2, 3]. Kittens that are severely affected may be reluctant to move at all [3] and need your help getting to their food, water, and litterbox until they’re feeling better.
Advice from Kitten Lady Hannah Shaw on taking care of kittens with limping syndrome
Virulent Systemic Feline Calicivirus (VS-FCV)
In rare instances, the FCV virus mutates into a much, much more dangerous form called virulent systemic feline calicivirus (VS-FCV) [2, 3]. VS-FCV is able to infect multiple organ systems and the lining of blood vessels [2, 3]. It causes high fever, inflammation throughout the body, swelling of the head and limbs, sores on the face and feet, jaundice, and multiorgan failure [1-3]. About 60% of cats infected with VS-FCV die [1-3]. Fortunately, outbreaks are very rare [1-3] and have only been observed in some countries [3]. Researches have not found any genetic traits that distinguish VS-FCV strains from regular FCV strains, however, making it difficult to specifically vaccinate against VS-FCV until there’s a breakthrough [2].
Treatment and Prevention
FCV usually goes away on its own in healthy cats [1-4]. There are currently no antiviral drugs that are proven to be effective against FCV, although a couple have shown promise in preliminary research [2]. As such, treatment focuses on relieving symptoms and supporting your cat’s body while it fights off the virus [1-4]. Your veterinarian might decide to prescribe medication like a non-steroidal anti-inflammatory drug or anticongestant [1, 2, 4]. Keeping the eyes and nose clean is important–nebulizers and saline eye or nose drops can help [1, 2, 4]. Some cats may need intravenous fluids [1, 2, 4]. Since many cats lose their appetite or simply find eating difficult, you may have to try different foods or ways of presenting their food to make sure they eat [1, 2, 4]. In severe cases, they may require a feeding tube [1, 2, 4].
The bad news is that FCV is extremely widespread. The good news is that there is a vaccine for it, which the American Association of Feline Practitioners [5] and European Advisory Board on Cat Diseases [2] both consider a core vaccine that all cats need to have. FCV is usually included in a combination vaccine with other common viruses [2].
Because there are so many different strains of FCV, the vaccine doesn’t always prevent a cat from becoming infected, but it is effective at preventing them from getting sick [2, 5]. Kittens lose the protection of the immune cells they get from their mothers somewhere between 6 and 14 weeks of age, so the American Association of Feline Practitioners recommends vaccinating kittens against FCV at 6 weeks, or as early as is allowed in your country [5]. Kittens should receive a primary vaccination series of 2-3 shots, and adult cats should receive a booster every 1-3 years, depending upon their risk level [2, 3, 5].
Hofmann-Lehmann, R., Hosie, M. J., Hartmann, K., Egberink, H., et al. (2022). Calicivirus infection in cats. Viruses, 14(5), 937. https://doi.org/10.3390%2Fv14050937
Feline Infectious Peritonitis (FIP) is a severe multi-organ-system viral disease that affects domestic cats as well as other felines [2, 5]. Until very recently, a diagnosis of FIP was a death sentence for a cat. It is still often fatal. However, knowledge is power. Knowing when to go to the vet and what your options are can save a life.
What Causes FIP?
FIP starts with an intestinal virus called feline enteric coronavirus (FeCV or sometimes FCoV). You can’t catch this coronavirus; only felines can [1, 4, 5, 9]. FeCV is very common among cats, especially in places where many cats live close together like shelters and catteries [1, 2, 5, 8]. Most cats infected with FeCV experience no symptoms, mild diarrhea, or mild respiratory illness before defeating the infection on their own [1, 4, 5, 8, 9]. In the meantime, they can easily spread the infection through their fecal matter or, less often, saliva [1, 2, 4-6]. Cats usually become infected by getting the virus in their mouths [1, 5, 6]. Shared litter boxes are a typical culprit [1, 2, 4-6]. An uninfected cat needs only to step in the litterbox after an infected cat has used it, and then when they clean their paws later, they become infected themself.
But what does this benign virus have to do with FIP? It isn’t well understood, but in about 10% of cats a FeCV infection turns into FIP [1, 2]. This is believed to occur as a combination of two phenomena. First, FeCV undergoes a spontaneous mutation that enables it to infect macrophages, a type of white blood cell [1, 2, 5, 8, 9]. This is the feline infectious peritonitis virus (FIPV). Second, the immune systems of certain cats overreact to the mutated virus, causing out-of-control inflammation and damage [1, 4, 6]. Incidentally, it is an overblown immune reaction to the coronavirus of the moment, COVID-19, that makes it so dangerous for a proportion of the population.
In the bodies of cats where both of these things happen, FIP develops. Some cats are more prone to FIP than others. Although the specific genetic risk factors remain unclear, specific breeds are at greater risk: Abyssinians, Bengals, Birmans, Himalayans, Ragdolls, Cornish Rexes, and Devon Rexes [6, 8]. Younger cats and most especially kittens make up the majority of FIP cases [1, 4, 6]. Their weaker immune systems are less able to fight off a FeCV infection, giving it more time to mutate [5]. Unneutered cats also seem to be at greater risk, for unknown reasons [8].
Symptoms of FIP – Image from Cornell University eCommons
Symptoms and Subtypes
The most common and earliest symptoms of FIP are, frustratingly, not very specific. They may include fever, change in appetite, weight loss, and depression [1, 5, 6]. As FIP advances, it develops into one of two general forms: wet/effusive or dry/non-effusive. In the wet form, fluid builds up in the abdominal and chest cavities and may cause breathing difficulty [1, 4-6, 8]. The dry form causes neurological and eye symptoms such as seizures and uveitis (inflammation of the outer layers of the eye) in addition to the non-specific symptoms [1, 4-6, 8].
Diagnostic Map for FIP (Hartmann, 2005)
Diagnosis
Diagnosing FIP is difficult and complicated. The symptoms can all be signs of other diseases. Once it is suspected, there is no definitive, foolproof test for FIP. At right is a diagnostic scheme for FIP from one scientific article as an example of the mental gymnastics veterinarians have to do when deciding how to pursue FIP testing.
The options include blood and fluid tests, genetic tests for FIPV, and the veterinarian’s observations during an exam [1, 2, 4-6]. Many of the tests are complicated by the fact that so many cats have been infected by FeCV [1, 2, 5]. A cat’s veterinarian has to determine the best course of testing based on their individual case.
Treatment
Until just a couple years ago, nothing could be done for cats with FIP except supportive care to ease their suffering and extend their life a short time. For many cats, that is still the case, for reasons I will get to shortly, or simply because their disease is too severe. Supportive care consists of subcutaneous or intravenous fluids, draining fluid from body cavities if applicable, steroids to control inflammation, and immunosuppressive medication [1, 2, 4-6].
GS-441524
GS-441524 is an antiviral drug that prevents viruses from synthesizing RNA, a molecule which many viruses, including FeCV/FIPV, use instead of DNA [3, 9]. It was created by the pharmaceutical company Gilead, which specializes in antivirals [9]. Gilead first tested GS-441524 against Ebola but was ineffective [9]. However, FIP researcher Niels Pedersen knew someone at Gilead and asked if they could send him anything to test [9]. His friend at Gilead obliged, and Pedersen found two promising candidates that killed FIP in cultured cat cells [9]. He moved on with testing one of them, GS-441524, in cats with FIP [9].
The results were incredible. In a laboratory study, ten of ten infected cats recovered [9]. In a field trial with 31 pet cats with non-neurological FIP, 25 recovered, still an unheard-of success rate for this otherwise inevitably fatal disease [7, 9]. A more recent pilot study suggests that GS-441524 is effective in neurological and ocular FIP, too [2]. Side effects were not too bad. Cats experienced pain and skin reactions at the injection site, sometimes developing sores or scars [7]. This may be because the formula is very acidic [7].
Gilead, however, has declined to license GS-441524 for animal use [9]. GS-441524 is almost identical, molecularly, to another one of their drugs, remdesivir, which they are trying to get licensed for human use, and they believe that licensing GS-441524 for FIP would harm their chances with remdesivir [9]. Cat people and Chinese entrepreneurs have gotten creative, however.
GS-441524 is not a difficult molecule to synthesize, so numerous outfits in China have chosen to manufacture and sell it, filling the gap Gilead left open [9]. Because GS-441524 is not FDA-approved, veterinarians cannot prescribe it, and it’s illegal for cat parents to purchase and administer it [1, 9]. That has not stopped desperate people who want to save their cats. Because it is a black market, there is a risk that the product will not be as advertised [1, 9]. And it is incredibly expensive: it costs 7,000-12,000 USD for the 12-week course of medication [9]. When people can manage to acquire it, however, GS-441524 seems to be as good as the research suggested [1, 9].
If your cat has been diagnosed with FIP, and you would like help accessing GS-441524 treatment, contact FIP Warriors.
Watch “Kitten Lady” Hannah Shaw’s journey through FIP with her cat Coco
Preventing FIP
Because FeCV is so common and easily spread, it’s hard to prevent FIP entirely. There are some things you can do, however. Keep litter boxes clean and far away from food and water dishes [1, 6]. Cats are more vulnerable to developing FIP if they have another disease like FeLV or FIV, so get your cats vaccinated against all those easily preventable diseases [1, 6]. There is one FDA-approved vaccine against FeCV, but it does not seem to be all that effective [1, 5, 6]. You can always ask your veterinarian about the FeCV/FIP vaccine if you’re concerned, however. Keep in mind that cats often get FeCV infections at animal shelters and catteries, so you may want to isolate any new cats for a couple weeks [1, 5].
Works Cited
Cornell Feline Health Center. (2020). Feline infectious peritonitis. Cornell University College of Veterinary Medicine. Link
Diaz, J. V. & Poma, R. (2009). Diagnosis and clinical signs of feline infectious peritonitis in the central nervous system. The Canadian Veterinary Journal, 50(1), 1091-1093. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2748294/
Dickinson, P. J., Bannasch, M., Thomasy, S. M., Murthy, V. D., et al. (2020). Antiviral treatment using the adenosine nucleoside analogue GS-441524 in cats with clinically diagnosed neurological feline infectious peritonitis. Journal of Veterinary Internal Medicine, 34(4), 1587-1593. https://doi.org/10.1111/jvim.15780
Pedersen, N. C., Perron, M., Bannasch, M., Montgomery, E., et al. (2019). Efficacy and safety of the nucleoside analog GS-441524 for treatment of cats with naturally occurring feline infectious peritonitis. Journal of Feline Medicine and Surgery, 21(4), 271-281. https://doi.org/10.1177/1098612X19825701
Pesteanu-Somogyi, L. D., Radzai, C., & Pressler, B. M. (2006). Prevalence of feline infectious peritonitis in specific cat breeds. Journal of Feline Medicine and Surgery, 8(1), 1-5. https://doi.org/10.1016/j.jfms.2005.04.003
Whiskers, known in the scientific world as vibrissae, are sense organs common among mammals. Because humans completely lack these specialized hairs, it is difficult, if not impossible, for us to really understand what animals that have them experience. It is a completely different, sixth sense that enables them to learn about their environment in a way that we cannot. Research has given us mere humans insight into how whiskers function, though, and how to be considerate of our furry friends’ precious whiskers.
Whiskers on Kittens
A whisker is a long, thick hair, which grows from a hair follicle like a cat’s fur does (2, 4). However, the hair follicles that make whiskers are different from the ones that make fur in a few important ways. For one, whiskers are rooted three times deeper into the skin than regular hairs (2, 6). The follicles for whiskers also have far more blood vessels and nerves (2, 4, 6). This heightens the sensitivity of the individual whisker hairs.
Cats have whiskers on their muzzles, chins, and forelegs; above their eyes; and near their ears (2-6). The number and length of whiskers varies. Most cats have 12 whiskers on either side of their noses (2, 6). Whiskers are usually light in color, but some cats may have black or brown whiskers, or a mix of colors. The color of a cat’s whiskers may even change over their lifetime (6, 7).
How Do Whiskers Work?
Although whiskers are sometimes called tactile hairs, the whiskers themselves don’t have any sense of touch. Rather, the movement of the whiskers triggers the nerves in the hair follicle, and that information is sent to the brain (2, 4, 5). This can tell a cat about the location, size, movement, and texture of an object as well as more general environmental information (2-5).
On the end of each whisker is a tiny organ called a proprioceptor (2, 4). Proprioceptors detect vibrations in the environment (4). They enable a cat to sense the position of its own body and all the components thereof in space (2, 4).
What Are Whiskers For?
Animals use whiskers for a lot of different things. Scientists have discovered that, depending upon the species, whiskers are involved in “food acquisition, prey attack, aggression and attack behavior, facial expression in intraspecies communications, dispersion of pheromones, maintaining head position in swimming, and a wide range of environmental monitoring (e.g. current detection in water, wind direction on land)” according to A. S. Ahl (1). Even in cats alone, whiskers serve a variety of functions.
Most cats have 12 whiskers on each side of their nose – Image by birgl from Pixabay
Cats are somewhat farsighted. Whiskers compensate for the trouble cats have focusing on objects close-up (2, 6, 7). This can be particularly important for hunting. Once a cat pounces on their prey and has it in their paws, their whiskers help them “see” to tussle with it and deliver the fatal bite (2, 4, 6). Many of the animals cats prey on also have whiskers, though, which can help them to sense cats coming (5).
A cat’s whiskers tell them if they can fit into a space or not (2, 4, 6, 7). Their muzzle whiskers are as long as they are wide (4, 6), so whether the whiskers bend when a cat puts its head in a space tells it if the rest of its body will fit. Whiskers don’t just protect cats from getting stuck in tight places, though. They also protect delicate parts of their bodies from damage (2). The whiskers on the face, especially those above the eyes, alert cats to objects that pose an imminent risk to their eyes (2). Whiskers can detect trouble as small as a speck of dust.
Whiskers serve a social function, as well. Cats communicate with each other mostly through body language. We can learn to understand these messages, too. The position of a cat’s whiskers provides one clue to their emotions. If your cat is relaxed, her whiskers will be as well, sticking straight out to the sides (4, 6). If they are excited, curious, or alert, they’ll push their whiskers forward (2, 4, 6). A cat that is angry or scared will pin their whiskers back against their face (4, 6).
Whisker Do’s and Don’ts
DO be mindful of whisker fatigue. Whisker fatigue is the pain and stress cats experience when their food and/or water bowls regularly brush up against their sensitive whiskers (3, 4). Tall, narrow bowls tend to be the culprit (3, 4). Be kind to your cat’s whiskers, and use wide, shallow bowls instead (3, 4, 6). Symptoms of whisker fatigue include:
Scooping food out of the bowl and eating on the ground
Making a mess while eating/drinking
Leaving food in the bowl but acting hungry
Approaching the food/water bowl with caution; pacing nervously before eating/drinking
Refusing to eat unless the bowl is full
Mealtime aggression (3)
DON’T cut your cat’s whiskers, ever. Number one, it’s painful for them (7). Number two, it disorients and confuses them (2, 4, 6, 7). For blind cats or cats that spend time outside, that is extra dangerous. There is no health reason to trim a cat’s whiskers, and it is not worth it just for aesthetic reasons.
DO check with your vet if you feel like your cat is losing a lot of whiskers. Whiskers fall out and are replaced when they get old just like any other hair. However, losing many whiskers in a short period of time can be an indication that something is wrong. Numerous skin conditions such as acne, allergies, and infections can cause whisker loss (7). So if your cat is losing whiskers frequently or en masse, consult your veterinarian (7).
DON’T play with a cat’s whiskers. Whiskers are cute, and it’s tempting to touch them, but most cats will find anything more than a gentle stroking uncomfortable. If you find a shed whisker, however, go nuts. I have a friend that uses her cats’ shed whiskers as tiny paintbrushes.
Fun Facts
Some cats may have curly whiskers, especially if they are of a curly-coated breed.
The word “whisker” dates back to about 1600. It comes from the Middle English “wisker,” meaning anything that whisks or sweeps. (4)
Each individual whisker can be traced to a specific spot in a cat’s brain. (2)
Works Cited
Ahl, A. S. (1986). The role of vibrissae in behavior: A status review. Veterinary Research Communications, 10, 245-268. https://doi.org/10.1007/BF02213989
Thyroid disease is fairly common in cats, especially as they get on in years. The most frequent type of thyroid disease in older cats is hyperthyroidism [1, 4]. My parents’ elderly cat, Rosie, has it. So did my roommate’s cat Coco. And so do my best friend’s two ancient gray ladies. Even though hyperthyroidism is a common illness, I will attest that it can still be mystifying at times. It can impact a cat’s entire body, and it isn’t completely understood even by scientists and veterinarians. It is diagnosable and treatable, however. Sometimes, hyperthyroidism can even be cured.
The thyroid gland – Image from Cornell Feline Health Center
What is Hyperthyroidism?
The thyroid gland is a small organ found in all vertebrates which produces the thyroxine (T4) and triiodothyronine (T3) hormones. In mammals, the thyroid is found in the throat and has two lobes. Thyroid hormones regulate a wide variety of bodily functions. When the thyroid produces too much T3 and T4, it’s called hyperthyroidism. Hyperthyroidism increases the body’s metabolism which can cause problems with many different organs and systems.
Cats typically develop hyperthyroidism when middle-aged or older [1, 2, 7, 8, 10]. Up to 10% of cats age 10 and older may have hyperthyroidism [1, 3, 8]. It’s uncommon in cats younger than that, however [1, 2, 7, 8]. Untreated hyperthyroidism is fatal, but today the prognosis for a cat with this disease is usually optimistic.
How is Hyperthyroidism Diagnosed?
If your veterinarian suspects hyperthyroidism, they will probably do a physical examination of your cat’s neck to see if they can feel that the thyroid is enlarged [1, 2, 4, 7]. The presence or absence of a suspicious lump isn’t enough for a diagnosis, however. Most of the time, the final diagnosis can be made with a total thyroxine, or TT4, blood serum test [10]. The vast majority of hyperthyroid cats will have very high T4 levels with a TT4 test, making the diagnosis clear right away [1, 2, 7, 10].
However, cats with hypothyroidism occasionally have T4 serum levels that fall within normal limits [1, 2, 7, 10]. T4 levels fluctuate, so your veterinarian may decide to try the test again in a few weeks [1, 7]. Or they might try other thyroid hormone blood tests. A thyroid scan is another option but must be performed at a specialty veterinary facility [7, 10].
What are the Symptoms?
Because thyroid hormones affect so many parts of the body, the symptoms of hyperthyroidism are varied and sometimes nonspecific. They include:
Characteristic appearance of hyperthyroid cat – Image from Cornell Feline Health Center
Weight loss/muscle wasting
Increased appetite
Increased thirst and urination
Vomiting
Diarrhea
Hyperactivity
Unkempt fur
Aggression or irritability
Fast heartrate
Increased vocalization, especially at night
Weakness
Heat intolerance
Some cats demonstrate “apathetic hyperthyroidism,” where they are lethargic, anorexic, and depressed/dull instead of the more usual symptoms [1]. Hyperthyroidism is progressive, so symptoms may be very mild at first [2]. It’s also not uncommon for hyperthyroid cats to also have other diseases, especially since they tend to be older. Many of these symptoms can be symptoms of something else. The safest bet is to consult your veterinarian anytime your cat seems different or unwell.
Secondary Illnesses
An overactive thyroid can sometimes cause other organs to become diseased. The heart is particularly at risk. There is a form of heart disease known as thyrotoxic cardiomyopathy which is caused by the heart muscle working overtime to meet the demands of a metabolism on overdrive [10]. The heart muscle thickens as a result of pumping so hard, but then that makes it difficult for the heart to work properly [2, 4, 10]. This can lead to heart failure. Fortunately, successful treatment of the hyperthyroidism can improve and even reverse the cardiomyopathy [2, 7, 10].
Hyperthyroid cats frequently experience high blood pressure as a cardiac complication, too [2, 4, 10]. About 25% of the time, in fact [10]. In severe cases, the high blood pressure can damage their organs [2, 4, 10]. It can even lead to retinal detachment that renders them permanently blind [4, 10]. High blood pressure is no joke and needs to be managed alongside hyperthyroidism until the thyroid hormones are under control [2]. If the hyperthyroidism is resolved, the blood pressure usually takes care of itself [2, 10].
What Causes Hyperthyroidism?
Hyperthyroidism usually begins when the thyroid gland becomes enlarged [2, 10]. In cats, this is almost always the result of a benign tumor called an adenoma [2, 4]. In less than 2% of cases, the growth is cancerous [1, 10]. What causes the abnormal thyroid tissue growth to begin with, however, remains uncertain. Researchers have found evidence for both environmental and biological factors that may play a role.
Environment
There is a demonstrated association between diet and the chances of a cat developing hyperthyroidism. Too much iodine in the diet may make a cat susceptible [10]. Canned cat food is also associated with higher rates of hyperthyroidism [1, 5]. The results of a 1999 study suggest cats fed primarily canned food have a rate of hyperthyroidism 2 to 3 times higher than other cats [5]. Researchers still don’t know why canned food would lead to an overactive thyroid. Correlation is not causation, so there may be more going on here that we don’t understand yet.
Using cat litter has also been found to be a potential risk factor, with the same study showing triple the rate of hyperthyroidism in cats that use litter [5]. Again, although there is a potential link, there is as yet no explanation. From looking through a lot of research papers to write this article, I know that veterinary scientists are still hard at work trying to figure out feline hyperthyroidism. The disease just doesn’t want to give up its secrets easily.
Certain household chemicals are associated with higher rates of feline hyperthyroidism, too. Polybrominated diphenyl esters (PBDE), which are used as flame retardants, have been found in high levels in the blood serum of hyperthyroid cats [1]. According to the Environmental Protection Agency factsheet for PBDE, rodent studies have shown thyroid toxicity from PBDE exposure. Per- and polyfluoroalkyl substances (PFAS) are a versatile group of artificial chemicals with a wide variety of applications in industry and the home. Wang et al. found that PFAS levels, particularly perfluorooctanoic acid, were higher in hyperthyroid cats than the cats in the control group [9]. The Environmental Protection Agency lists tumor growth and thyroid hormone disruption among the effects of PFAS in animals.
Siamese have a reduced rate of hyperthyroidism – Image by rihaij from Pixabay
Biology
Hyperthyroid cats may have defects in the way their cells communicate that lead to the adenomas and other tissue abnormalities that overproduce thyroid hormones. Cats with thyroid nodules sometimes have low levels of the G protein in their thyroids [1]. A lack of G protein can decrease the inhibition of cell growth [1]. Some cats with thyroid nodules or adenomas have a cancer-causing mutation, known as an oncogene, which could cause the excessive cell growth [1].
Certain breeds of cat are less likely to develop the disease: Siamese, Burmese, Tonkinese, Himalayan, Persian, Abyssinian, and British Shorthair [3, 5, 9, 10]. At one time, only the Siamese, Burmese, and Persian/Himalayan were known to have these decreased risk, so the benefit was thought to be associated with the color-point pattern or lighter coat colors [3]. This hypothesis ultimately didn’t hold up [3], but perhaps there is something special these breeds have in common which will one day come to light. The same study which discovered the three new resistant breeds also found that long-haired, nonpedigree cats have higher rates of hyperthyroidism [3]. This despite the extremely long-haired Persian and Himalayan’s decreased rate.
What Treatments are Available?
Radioactive Iodine
It might sound a little scary, but radioactive iodine is actually the gold standard for treating feline hyperthyroidism. This treatment can only be done in specialized veterinary clinics that are authorized to work with radioactive materials, so it may not be accessible or affordable for everyone [2, 7, 10]. It’s a great option if you can take it, though, because for about 95% of cats it cures their hyperthyroidism–even those few with cancerous thyroid tumors [1, 2].
Radioactive iodine therapy relies on the fact that the thyroid takes up iodine to synthesize thyroid hormones. The cat is injected with the radioactive version of iodine, I-131 [1, 2, 7, 10]. No anesthesia is required [2, 7, 10]. The cat’s thyroid absorbs the I-131, just like it would normal iodine, but the abnormal thyroid tissue that’s churning out T3 and T4 like crazy is hogging the iodine. So the radioactive molecules get sucked into the abnormal tissue and kill it, leaving alone the cat’s healthy tissues, including any healthy thyroid tissue [1, 2, 7, 10].
Although the procedure is quite safe for the cat, it can be dangerous for the people around the cat which is now shedding radioactive particles [2]. Cats have to be hospitalized for a week or two after radioactive iodine therapy so that their radiation levels can get low enough for release [1, 2, 7, 10]. Even then, special care has to be taken at home for a two weeks after [1].
Radioactive iodine therapy may be a good option for cats that cannot undergo anesthesia. It also works well for cats with ectopic thyroid [7]. Ectopic thyroid is thyroid tissue somewhere other than the usual location of the thyroid gland such as under the tongue or in the chest [10]. It can be in locations that would be difficult to remove surgically. Radioactive iodine therapy doesn’t usually have complications, but for the rare cat it works too well and they become hypothyroid instead [2]. The solution to this is medication with thyroid hormones.
Medication
Hyperthyroidism cannot be cured with medication, but it can be managed with it. The medicine is called methimazole [1, 4, 7, 10]. Its brand names are Felimazole and Tapazole [4, 7, 10]. Methimazole is available as an oral tablet or a gel applied to the skin [1, 2]. It works by decreasing the production and release of hormones from the thyroid [2, 4]. It’s usually given twice a day [1, 4].
Cats may be given methimazole as a long-term method of managing their disease or to stabilize them before trying a more permanent solution [1, 4, 7]. Like all drugs, methimazole can have side effects. According to the Food and Drug Administration, the most common side effects of methimazole in cats are changes in appetite, lethargy, vomiting, diarrhea, skin lesions, itchiness, unusual vocalizations, weight loss, fur abnormalities, weakness, and agitation [4]. However, a small percentage of cats develop severe side effects with methimazole [1, 4]. Namely, liver disease, anemia, low blood platelets, and low white blood cell counts [1, 4, 7, 10]. Always report medication side effects, even seemingly small ones, to your veterinarian.
When Dr. Jean Holzworth first recognized feline hyperthyroidism in 1978, the only way to treat it was to remove the offending thyroid gland [1]. Although there are now other options, for some cats this is still the chosen course of treatment. For most cats, surgery cures their hyperthyroidism [2]. It can also be done at a regular veterinary surgery rather than the special facility required for radioactive iodine therapy, making it accessible to more people. Surgery requires a cat to go under anesthesia, however, and for older cats who often have other health problems, that can be a risky proposition [2, 10].
Surgery also carries a chance of complications. Complications aren’t likely, but they do happen. Most cats still have enough thyroid cells left after the surgery to keep up their T3 and T4 hormone levels, but some become hypothyroid and require medication [7]. Another possible complication is damage to the parathyroid glands, which are near or within the thyroid are necessary for maintaining normal calcium levels in the blood [2, 7]. If the parathyroid glands become damaged, the cat may develop low blood calcium and require supplemental calcium or vitamin D [1, 7]. Other complications include damage to nearby nerves or the larynx [1, 7].
Due to the risks associated with surgery and the availability of alternatives, it isn’t a very common choice anymore [2]. That being said, it might still be the right option for you and your cat. That’s something you would have to figure out with your veterinarian.
Diet
The research is still ongoing for diet as a means of controlling hyperthyroidism in cats [2]. For cats with health concerns that make other treatment options difficult or impossible, however, it can be the best–or only–choice despite being somewhat controversial. The principle is that limiting the amount of iodine in the cat’s diet to a small, controlled amount restricts the amount of hormones the thyroid can make. Cats fed a prescription iodine-restricted diet and nothing else should return to normal thyroid function [1, 7, 10]. Nothing else really means NOTHING else. No treats, don’t even put the prescription food in a bowl that has been used for other food or untreated water [1, 10]. The iodine-restricted diet contains only 0.2 parts per million of iodine [10]. That is a really, really small amount. It would not take much to throw off the balance.
Crossley, V. J., Debnath, A., Chang, Y. M., Fowkes, R. C., et al. (2017). Breed, coat color, and hair length as risk factors for hyperthyroidism in cats. Journal of Veterinary Internal Medicine, 31(4), 1028-1034. https://doi.org/10.1111/jvim.14737
Kass, P. H., Peterson, M. E., Levy, J., James, K., et al. (1999). Evaluation of environmental, nutritional, and host factors in cats with hyperthyroidism. Journal of Veterinary Internal Medicine, 13(4), 323-329. https://doi.org/10.1111/j.1939-1676.1999.tb02189.x
Peterson, M. E., Castellano, C. A., and Rishniw, M. (2016). Evaluation of body weight, body condition, and muscle condition in cats with hyperthyroidism. Journal of Veterinary Internal Medicine, 30(6), 1780-1789. https://doi.org/10.1111/jvim.14591
Stephens, M. J., O’Neill, D. G., Church, D. B., McGreevy, P. D., et al. (2014). Feline hyperthyroidism reported in primary-care veterinary practices in England: Prevalence, associated factors and spatial distribution. Veterinary Record, 175(18), 458. https://doi.org/10.1136/vr.102431
Wang, M., Guo, W., Gardner, S., Petreas, M., et al. (2018). Per- and polyfluoroalkyl substances in Northern California cats: Temporal comparison and a possible link to cat hyperthyroidism. Environmental Toxicology and Chemistry, 37(10), 2523-2529. https://doi.org/10.1002/etc.4239
Happy Spring Equinox! Spring is the season of new life, and that includes new kittens. Two weeks ago, we looked at the reproductive cycles and mating behavior of cats. Now, we look at what naturally comes next. I’ll cover the stages of cat pregnancy, birth, and the basics of kitten development. Additionally, I will continue to debunk common myths about feline reproduction.
Cat Pregnancy
A she-cat carrying or raising kittens is called a queen. Queens are pregnant for approximately nine weeks (2, 5, 6, 9). About three weeks in, queens begin to show signs of pregnancy (9). This is also when it first becomes possible to confirm pregnancy because a veterinarian can then feel the kittens inside the abdomen (8, 9). An ultrasound will also do the trick (8). The symptoms of a cat pregnancy include:
Weight gain (4, 9)
Increased appetite (2, 9)
Dark/pink, swollen nipples (2, 4, 9)
If you have a pregnant queen on your hands, make sure to feed her food approved for “growth and reproduction” life stages. This is usually labeled as kitten food, but it has the nutrients queens need to nourish themselves and their kittens as well. As her pregnancy progresses, she will need her food delivered in frequent, small meals (8). There is less room for food in there, after all!
As a cat nears the end of her pregnancy, she begins looking for a nesting site (2, 5, 8, 9). In the wild, a queen seeks out a dry, safe, hidden, and defensible location to kit. She usually picks out several so that she has places to move her kittens if danger threatens the original nest. An indoor cat will exhibit essentially the same behavior. She may appreciate being provided with a box, basket, or bed lined with soft bedding (5, 8, 9). Or she may choose to have her kittens under the kitchen sink, or some other weird place. She will pick wherever she thinks is safest. When the time comes, cats give birth to an average of four kittens (2, 4).
Birth
When a queen is near to kitting, she will probably visit her nest site(s) repeatedly and make adjustments to the bedding (4). She may become restless or anxious (8). Queens with humans may act more affectionate and seek comfort, or do the opposite and become withdrawn (4, 9). They may meow, purr, or pant (4, 5). The queen cleans around her vulva and nipples (5). This is thought to strengthen her scent there and lay a trail for the newborn kittens to follow toward the milk supply (5). During this time contractions begin, but no kittens appear (5). This first stage of labor can last as long as 36 hours in new mothers (4).
When the queen enters the next phase of labor, the contractions strengthen and the first kitten is born (4). The placenta soon follows (4). As soon as she pushes each kitten out, the queen bites open the amniotic sac that surrounds them, licks their mouth and nose clear, and bites off the umbilical cord (4, 5). The queen eats the placentas and licks her kittens to clean them and stimulate them to breathe (4, 5). The time interval between kittens varies from ten minutes to an hour (4). Sometimes, labor may stop after one or more kittens, only to resume as much as 36 hours later to deliver the rest (4).
With the exception of some purebred cats, queens usually kit without a hitch. If you have a pregnant cat, though, make sure you know the phone number of both your veterinarian and the nearest emergency vet just in case. If you think anything seems wrong, call. Make sure you know ahead of time how many kittens to expect so you know if somebody hasn’t arrived yet. Get in touch with a vet if your queen has had contractions for more than an hour with no kitten arrival or if two hours have gone by without the next birth (8). If a kitten has been in the birth canal more than a minute or two, take your cat straight to the vet (8).
Myth #1: If you touch very young kittens, the mother cat will abandon them.
Scent is very important to cats. There’s no doubt about that. And queens do occasionally abandon one or more kittens for a variety of reasons: the kittens may be sick, deformed, or unresponsive (3, 5). But if this is your cat and her kittens we’re talking about, there’s no need to worry about touching the kittens. Your own cat who is familiar with your scent has no reason to be alarmed at finding it on her offspring (3). It will not cause her to reject them (3). You can even move the kittens to a safer nesting site if you need to–although there’s no guarantee their mother won’t move them again somewhere she likes better (3). Try not to separate the queen and kittens for the first few days if you can help it, however (8).
Myth #2: If you spay a cat that has kittens, she’ll stop producing milk for them.
This is a common belief that sometimes causes problems for people. It makes perfect sense, but it isn’t true. A queen can go on feeding her kittens even after she’s been spayed. In fact, spayed she-cats that have never given birth will start producing milk if a kitten suckles them long enough (3). They can help surrogate orphan kittens this way (3). She-cats start going back into heat shortly after giving birth, so this misconception can be dangerous. People who think they need to leave their she-cat intact to feed her kittens may get stuck in a cycle of perpetual kitting. Nobody can find homes for that many unplanned kittens. This is a myth we really need to dispel.
Kittens
Neonate (0-2 Weeks)
Kittens are born with their eyes closed and their ears folded shut. They can barely wriggle; walking is certainly out of the question. They also can’t control their body temperature or eliminate waste on their own (1, 7). Newborn kittens rely on their mother for everything, not just food. She keeps them warm and clean, she stimulates them to urinate and defecate, and she defends them from any danger. For the first 4-5 days, neonates (from the Greek for “new” and Latin for “born”) will still have the remains of their umbilical cords attached (7). It will then fall off on its own (7). These tiny kittens weight on average 100 grams (5, 7). They can’t do much and sleep most of the time. They can purr and make distress calls, though, so they can communicate with the queen (1).
During the first week, kittens’ ears slowly start to open up (1, 7). Their eyes follow suit a couple days later (1, 7). All kittens are born with blue eyes. At the end of the first week, kittens will have doubled their birth weight (1, 5, 7). Over the course of the second week, their eyes and ears will finish opening, although their vision will take a while to reach its full potential (1, 7). Two-week-old kittens can walk a bit, but they are awfully wobbly (1, 7). Kittens this age will also start to hiss at unfamiliar scents or sounds (1). They can knead, but they cannot retract their claws yet (1).
Baby Tiger (3-5 Weeks)
A kitten’s first teeth, their incisors, come in at three weeks (1, 6, 7). They start to be able to eliminate on their own, and kittens in an indoor environment may experiment with the litter box (1, 7). They begin to be able to regulate their own body temperature as well (7). Kittens will start exploring and playing in earnest around this time (1, 6, 7).
A queen starts weaning her kittens when they are about four weeks old (5). In the wild, she also teaches them how to hunt (5). For pet cats, this is a good age to begin socializing kittens (1). Kittens at this age don’t have to be at their mother’s side every moment, so their people can start to spend some time getting them used to being handled. This is also the age when kittens’ fur coat fills out and things like markings and coat length become more apparent (1). At five weeks, a kitten’s eyesight is fully-developed, and the playtime starts to get wild (1).
Older Kitten (6-8 Weeks)
A six-week-old kitten has all of their baby teeth (7). This is typically the age when kittens are brought to the veterinarian for their first exam and vaccinations (1, 8). Kittens this age know how to clean themselves and will groom their littermates, too (1). At seven weeks, their adult eye color starts to develop (7). Some cats will keep their blue eyes, but most will change to another eye color.
At eight weeks, kittens are usually fully weaned (1, 6, 7). Kittens are sometimes adopted out at this age, as they are pretty independent from their mother. It is possible to spay/neuter kittens at eight weeks if they have reached two pounds (0.91 kg) (1, 7).
Watch Gourdon and Pepita grow up in 10 minutes! Not for those with misophonia.
Teenager (3-12 Months)
Although growth slows down a bit, a lot still has to happen before a kitten’s first year is over. They will shed their baby teeth and grow permanent ones (6). They’ll go through puberty around six months old and she-cats will have their first heat cycle (6). By that age, kittens are 80-90% of their final size (6). Teenage cats push boundaries and try new things, trying to get a sense of the world and their place in it (6). They’ll put on more muscle mass (6) and start to lose their kitten fluff. Kittens are quite fully mature at the end of their first year, but they’re almost there (6). A few more months and they’ll be all grown up (6).
Myth #3: Kittens must be six months old before they can be spayed/neutered.
It used to be the conventional wisdom that kittens needed to be six months old to be sterilized. Sometimes veterinarians may still recommend this. However, we now know that she-cats can have their first heat as early as four months old, and they can have kittens the first time they go into heat. In other words, it’s possible for a kitten to have kittens, which can lead to complications that a full-grown queen would not have. These days, it is becoming more common to instead recommend that a kitten be at least eight weeks old and at least two pounds (0.91 kg) to be sterilized (1, 6, 7). This prevents a lot more unwanted heat cycles and pregnancies.
