Cats Domesticated Themselves, Ancient DNA Shows
A comprehensive survey of cat genes suggests that even after felines wandered into our lives, they remained largely unchanged for thousands of years.
In a new comprehensive study of the spread of domesticated cats, DNA analysis suggests that cats lived for thousands of years alongside humans before they were domesticated. During that time, their genes have changed little from those of wildcats, apart from picking up one recent tweak: the distinctive stripes and dots of the tabby cat.
Researchers surveyed the DNA of more than 200 cats spanning the last 9,000 years, including ancient Romanian cat remains, Egyptian cat mummies, and modern African wildcat specimens. Two major cat lineages contributed to the domestic feline we know today, they report in a study published Monday in Nature Ecology & Evolution.
The earlier ancestors of today’s domestic cats spread from southwest Asia and into Europe as early as 4400 B.C. The cats likely started hanging around farming communities in the Fertile Crescent about 8,000 years ago, where they settled into a mutually beneficial relationship as humans’ rodent patrol. (See little-known small cats in “Out of the Shadows, the Wildcats You’ve Never Seen.”)
Mice and rats were attracted to crops and other agricultural byproducts being produced by human civilizations. Cats likely followed the rodent populations and, in turn, frequently approached the human settlements.
This is probably how the first encounter between humans and cats occurred, It’s not that humans took some cats and put them inside cages. Instead, people more or less allowed cats to domesticate themselves. (Also see “Surprising Things You Never Knew About Your Cat.”)
A second lineage, consisting of African cats that dominated Egypt, spread into the Mediterranean and most of the Old World beginning around 1500 B.C. This Egyptian cat probably had behaviours that made it attractive to humans, such as sociability and tameness.
The results suggest that prehistoric human populations probably began carrying their cats along ancient land and sea trade routes to control rodents.
Tabby Takeover
By comparing the DNA of cats throughout history, the study captures a glimpse of how the animals were changing even before humans started to cart them across the globe.
Surprisingly, wild and domestic cats showed no major differences in their genetic makeup, and one of the few traits available for telling them apart was the tabby coat marking.
The study sheds light on the late emergence of the blotched or striped coat markings, which began to appear in domesticated tabby cats in the Middle Ages. The gene for a tabby coat dates back to the Ottoman Empire in Southwest Asia and later became common in Europe and Africa.
It was only in the 18th century, however, that the markings became common enough to be associated with domestic cats, and in the 19th century, cat fanciers began selecting cats with particular traits to create fancy breeds.
Purr-fect Pets
Overall, cats became a domesticated companion of humans without changing much. Domestic cats look similar to wildcats, but they aren’t solitary, tolerating both humans and other cats. (See “Our Most Stunning Pictures of Big Cats.”)
This is in contrast to dogs, the first animals to be domesticated. Dogs were selected to perform specific tasks—which never was the case for cats—and this selection for particular traits is what led to dogs’ diversification to the many breeds we see today.
There was no need to subject cats to such a selection process since it was not necessary to change them. They were perfect as they were.
Though everyone might not agree on cats’ perfection, felines are among the most popular pets in the world today, with as many as 74 million cats living in U.S. homes.
We’re discovering incredible things about where they’ve come from, how far they’ve gone, and what kind of impact they’ve had on humans. I think studying more about this species is going to open up even more about the domestication process.
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Surprising Things You Never Knew About Your Cat
For starters, our pet felines’ personalities are linked to their color.
A paradoxical blend of needy and aloof, cuddly and conspiratorial, one of the world’s most popular furry friends continues to delight and befuddle those of us who live with them.
So after writing How to Speak Dog for National Geographic Books, it seemed natural to follow it up with a feline version. The result is his new book, How to Speak Cat.
You’ve been a veterinarian for 25 years, so you’ve probably pretty much seen it all in terms of cat behavior. But was there anything new that you learned while writing the book?
There’s the basic kind of facts that I learned, like Guinness Book of World Record-type things, that I really didn’t know. [For example], the oldest living cat, [now deceased], was 27 years old out here in Point Loma, California. (Watch a video on why cats are so secretive.)
But I learned that scientists think that cats respond better to women, because women have higher-pitched voices than men. These facts are in bold print on every other page in the book, and nearly all of them surprised me.
Besides starring in YouTube videos, do cats have any other remarkable abilities that you learned about while writing this book?
Cats can see in the dark six times better than humans. That’s not something you learn in vet school, and you don’t learn that working in a shelter or working with animals for decades. But six times better than a person—that’s pretty impressive. (Also see “How Cats and People Grew to Love Each Other.”)
PHOTOGRAPH BY DAVID ROTHBARD, NATIONAL GEOGRAPHIC YOUR SHOT
A cat’s breed can certainly affect its appearance, but can it affect a cat’s personality?
Definitely. The color of coat is linked to behavior. For example, tortoiseshell cats, torties, can be independent and they usually like just one person, and they can be pushy about what they want. Torties and calicos and Abyssinians all have strong documented links between their coat color and personalities. More anecdotal is the orange tabby, who is the poster child for the most gregarious. But personality really seems to go with coat color.
When people ask you questions about their cat’s seemingly bizarre behavior, what are their most common issues?
One of the biggest questions I get is why does my cat become a psychotic rocket and suddenly go from 0 to 60 and zoom around the living room. We don’t really know for sure, but indoor cats especially have a lot of pent-up energy that they can’t exercise, whereas wild cats have hunting, stalking, and waiting on edge to keep them busy. It’s an energy release. That’s really what it is. The other question is why is my cat not using the litter box correctly, which is, not to be funny, the number one question I get. (See National Geographic readers’ pictures of cats.)
Speaking of wild cats, how similar is our average house cat to its wild ancestors?
They’re very, very similar. Domestic cats have only been around for half the time that dogs have, so you can see almost the same behavior among lions, tigers, and leopards that you do among domestic cats. That is, perhaps, one of the biggest draws of these animals—we can live harmoniously with them and still get to watch Mutual of Omaha every day. They’re still part wild. They haven’t gone to finishing school yet. (See “Our Most Stunning Pictures of Big Cats.”)
With so many big cat species endangered, can our love for domestic cats help save their wild cousins?
Look at the almost universal outrage over the death of Cecil the Lion this summer. People love cats. Cats, hands down, own the Internet. That’s the leverage that we have to try and stop some of the astonishingly bad practices towards the other cats on our planet.
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Dogs will eat almost anything—cats, not so much. Here’s why.
There’s a reason why your dog will scarf down a cookie while your cat turns up its nose—and it’s all in the genes, say scientists.
PHOTOGRAPH BY WILLARD CULVER, NAT GEO IMAGE COLLECTION
Why are cats such picky eaters when dogs seem willing to wolf down just about anything they encounter? It’s a question many pet parents likely ask themselves while coaxing their feline friend to swallow a pill or prying another slobbery piece of mulch from their puppy’s mouth.
There’s still a lot scientists don’t know about animal taste preferences. But, thanks to a small but growing body of research, researchers are starting to unravel some of the mysteries around our four-legged friends’ flavor fancies. Here’s what we know so far.
What can cats taste?
Accidentally drop a cupcake on the ground and your dog will probably scarf it down in one bite. Your cat, on the other hand, may turn up her nose. One possible reason for their differing behaviors? Cats can’t taste sweetness.
Since they couldn’t just ask cats directly, researchers figured this out by analyzing their DNA. House cats, tigers, and cheetahs have a “broken” version of the gene Tas1r2, which works with another gene, Tas1r3, to enable sweetness detection. Though Tas1r3 appears to function perfectly fine in cats, Tas1r2 is an “unexpressed pseudogene” that’s missing 247 letters. Without them, Tas1r2 does not produce a crucial protein needed to form a receptor for sweetness on cats’ taste buds.
But if cats can’t detect sweetness, what can they taste? Given cats’ meat-centric diet, scientists long suspected they could taste umami, the rich, savory, meaty flavor Japanese speakers describe as the “essence of deliciousness.” And, recently, they found evidence to confirm this hunch. After sequencing the feline genome, they discovered cats express both genes necessary to form umami receptors on their taste buds, Tas1r1 and Tas1r3.
To take the study a step further, they gave 25 felines the choice between a bowl of plain water and one that’d been spiked with molecules that provide umami flavor. As expected, the cats strongly preferred the umami water, and more specifically, water containing umami compounds present in tuna. That may help explain why felines love the saltwater fish so much. We think umami is the main driver of intake for cats. Tuna hits the umami sweet spot for cats.
Dogs, by contrast, can taste sweetness and umami. And both cats and dogs have bitter taste receptor genes, though cats have 12 (seven of which are functional) and dogs have 15. What remains unclear, however, is how the number of bitter receptor genes affects the animals’ actual perception of bitterness.
You are (genetically) what you eat
The sense of taste helps animals evaluate potential food sources. Sweetness, for example, indicates a food is rich in carbohydrates, which are a good source of energy. Umami signals protein, while saltiness denotes sodium, an essential nutrient. Sourness is a bit more complicated, but scientists believe it may communicate acidity, which could be helpful for ingesting vitamin C or for determining if rotting fruit are actually safe to eat (since the “good” bacteria that makes them taste sour would kill off any “bad” bacteria during fermentation). The evolutionary purposes of bitterness are also up for debate, though the long-held belief is that it may signify toxicity.
The ability to detect these tastes shows up in animals’ DNA: Specific genes are responsible for producing different types of taste receptors on animals’ taste buds. Sometimes, these taste receptor genes randomly mutate. If the animal survives just fine with the mutation, they’ll pass that trait along to their offspring until, eventually, it becomes the norm. Scientists think this is likely why carnivorous cats can’t taste sweetness, why bamboo-eating pandas can’t taste umami, and why some marine mammals that swallow their food whole, like dolphins and whales, have no functioning taste receptor genes at all. At some point in history, some of these species’ taste receptor genes stopped working properly and, because of their dietary needs, they simply stayed that way. There’s a correlation between what you eat and what is reflected in your genome.
The taste differences between cats and dogs also make sense in the context of their diets. Cats are “obligate” carnivores, which means they can get all the nutrients they need from animal flesh. Dogs, on the other hand, are opportunistic feeders who take advantage of whatever food sources are available—whether meats, plants, or grains. “One reason why dogs may not be as fussy is because they are quite happy and able to eat a range of different foods.
‘Their own sensory world’
Pets perceive the world differently than we do. Understanding these differences could provide valuable insights not only for pet owners, but also for veterinarians, pharmaceutical companies, and pet-food manufacturers.
For example, if your cat has no appetite because of an illness, you might try amping up the umami in his food. To get cats with no appetite to eat food on their own, sprinkle a small amount of dried bonito flakes—which is a very common umami ingredient in Japan and contains a lot of the nucleotide inosine monophosphate—on their food, and it worked very well.
Leaning into the research could also lead to the development of supremely yummy foods and more palatable medicines for cats and dogs, though scientists say more work needs to be done to fully understand our pets. “Every species is living in their own sensory world,” says Jiang. “But our research is actually just the tip of the iceberg. There are lots of other things we clearly do not understand.”
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Cats have 276 facial expressions. Why?
Famously aloof felines may be more expressive than we thought. A new study looks at how cats interact with each other, and with us.
JOEL SARTORE
In fact, cats likely evolved these various expressions because of us—a product of communication between felines and humans over 10,000 years of domestication.
We have this very deep history with cats, and for that reason there is “growing interest” in how to decipher our cats’ emotions.
Most previous research on facial signaling in cats has focused on interactions between cats and humans or assessing when a cat is in pain. The new study takes that a step further by analyzing how cats interact with one another.
And what better place to do that, than a cat café? After 150 hours at the CatCafe Lounge in Los Angeles, California, a nonprofit shelter where visitors can meet up to 30 cats for potential adoption. (What do cats think about us? You may be surprised.)
Their observations of 53 domestic shorthair cats revealed a wide variety of expressions—which combine various movements of the eyes, ears, and lips—and that most of these were friendly, not aggressive. Many cat people would instantly recognize some of these as friendly, such as ears and whiskers forward and eyes closed.
But some, like what the researchers call “play face,” with ears and whiskers forward and mouth pulled back at the corners, don’t have such obvious meanings.
What’s more, a lip lick might suggest a cat is anticipating a treat, but when combined with narrowed pupils and flattened ears, it’s an unfriendly cue.
Whiskers overall are surprisingly telling: Content or happy cats almost always point their whiskers forward.
Is that a fake smile?
After hours at the cat café, Scott recorded 194 minutes of cat interactions, excluding non-communicative behaviors such as yawning or chewing.
Back at the lab, the team used a coding system for facial expressions called Facial Action Coding System, or CatFACS. Trained users can identify “even the most subtle of muscle movements, and each of these movements, called an “action unit,” is noted and given a number using a video software, ELAN. This allows users to create and edit a video-footage timeline, which can read expressions at the millisecond level.
The analysis revealed 26 unique muscle movements that, in various combinations, created 276 facial expressions. The results categorized 46 percent of expressions as friendly, while 37 were unfriendly, and 17 fell into both categories.
Examining the facial expressions at such a granular level can catch nuances. A good example is the real vs. fake smile in humans: Though in both situations you’re smiling, there may be small differences, say in eye movements, that can indicate whether you’re actually happy. (Read surprising things you never knew about your cat.)
For some feline expressions, though, the meanings are still a mystery, and the team is planning follow-up studies to figure them out.
A tool for improving cat welfare
It will be really interesting to see what groupings are more common in different situations and contexts.
Cats don’t need eye contact to make their intentions known. Body posture and other behaviors, such as guarding a food bowl, sends a signal that “this is mine,” without needing to make any facial expressions.
Research could inspire scientists to observe facial expressions in wild cat species, which are more solitary. Knowing whether wild cats share specific meaningful expressions would discern whether domestication led to a greater variety of expressions in domestic cats. (Learn why cats domesticated themselves.)
The research also has a practical application, says Bennett, who consults with shelter organizations. For instance, the study could help develop a standardized tool of facial expressions, allowing animal shelter staff and volunteers to identify certain cues and act accordingly.
In one scenario, if two cats are brought into the shelter together, they may be considered to be bonded. But recognizing differences in their facial expressions could suggest otherwise, and point the staff toward finding a more suitable feline friend.
“I’m excited about this, They definitely think they’re on the right track.”
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How Siamese cats change their colours
A genetic mutation known as the Himalayan gene has made this breed’s fur extra sensitive to temperature—but also leaves them vulnerable to certain health problems.
PHOTOGRAPH BY WILLARD CULVER, NAT GEO IMAGE COLLECTION
With 73 cat breeds recognized by the International Cat Association, it can be difficult to discern a Ragdoll from a Ragamuffin.
Most of us, though, can pick out a Siamese cat. Known for their dark eye masks, socks, and tail—called “points”—that stand out against their cream-colored bodies and sparkling blue eyes, the Siamese is one of the world’s easily recognized breeds.
Those trademark points stem from a genetic mutation known as the Himalayan gene, which was discovered in the breed in 2005. This recessive gene, passed down from both parents, also gives the felines temperature-sensitive fur that can change color.
In the womb, Siamese kittens develop at temperatures of about 101 Fahrenheit, a cat’s normal temperature. Once born, all-white kittens eventually begin to cool at their extremities, such as their tail, legs, ears ,and face. These lower temperatures cause the Himalayan gene to activate the body’s melanin, a pigment also found in people. That’s why a Siamese cat’s warmer bodies stay light, but their cooler parts become darker as they mature. (Read how tabbies get their stripes.)
You can see them change. At about two weeks old, dark hues begin to spread to their limbs. By about a month old, their final color emerges, which may be one of several varieties, among them blue point, lilac point, chocolate point, and seal point, which has a light, cream-colored coat with dark brown hues on its paws, tail, nose, and ears.
A lifelong influence
The Himalayan mutation naturally occurs in South Asian domestic cats, says Leslie Lyons, a feline geneticist at the University of Missouri who first identified the mutation in Siamese cats.
Over time, as people selectively bred cats with the striking pale color and dark points, they passed the gene to different breeds, such as Siamese, Birmans, Ragdolls, and Burmese. Mixed breeds can also carry the genetic mutation.
These cats’ vibrant blue eyes are also due to the Himalayan gene, which influences their eye pigment. (See vintage pictures of pampered pets.)
The Himalayan mutation causes fur to darken as the cat ages, though any sort of trauma or change to the cat’s fur can alter its hues.
If a Siamese cat has surgery, for example, an area of fur that was shaved may grow back darker because the impacted area is cooler while the hair grows back. Eventually, the fur may become lighter again, Arnold says.
In the 1920s, a Siamese cat living in Moscow that wore a jacket over a shaved shoulder had its fur grow back all white, since that area was kept warmer. The fur later turned darker again, according to the University of Alaska.
Health concerns
Many other species have the Himalayan gene, including Himalayan rabbits, says Lyons.
Domestic rats, color-pointed gerbils, and American minks can also carry the mutation. In 2021 the journal Gene reported a dachshund with a different mutation on the same Himalayan gene that produced Siamese-type coloration, a rare occurrence in dogs.
Each species has its own mutation in the same gene, but then have been bred to have the specific coloration. (Read surprising things you never knew about your cat.)
While there’s no overarching advantage or disadvantage to the mutation in these domestic animals, it does come with some health concerns, too, including eye issues.
Siamese often have crossed or misaligned eyes, also called strabismus, which can compromise vision as well as depth perception.
Even if the cat’s eyes are aligned, the animal may still suffer from nystagmus, or shaking eyes, a condition in which the eye sometimes dart slightly from side to side in repetitive, uncontrolled movements that can cause vision or even balance problems, says Arnold. She adds she hasn’t seen the condition in her practice.
Both Lyons and Arnold recommend pet owners get their Siamese pets from reputable breeders, or adopt them from a rescue. Wherever they’re from, though, both experts agree these masked felines will steal anyone’s heart.
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