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Monday, June 19, 2017

Ancient Egyptians may have given cats the personality to conquer the world | Science | AAAS

A cat in a domestic setting—eating under a dining table—sometime after 1500 B.C.E. 

Ashmolean Museum, University of Oxford/Bridgeman Images

Ancient Egyptians may have given cats the personality to conquer the world

Around 1950 B.C.E., someone painted an unusual creature on the back wall of a limestone tomb some 250 kilometers south of Cairo. With its long front legs, upright tail, and triangular head staring down an approaching field rat, it is unmistakably a domestic cat—the first appearance in the art of ancient Egypt. In the centuries that followed, cats became a fixture of Egyptian paintings and sculptures, and were even immortalized as mummies, as they rose in status from rodent killer to pet to god. Historians took all this as evidence that the ancient Egyptians were the first to domesticate the feline. That is, until 2004, when researchers discovered a 9500-year-old cat buried with a human on the Mediterranean island of Cyprus, revealing that cats had been living with people thousands of years before Egypt even existed.

A new study could put Egypt back in the limelight. A genetic analysis of more than 200 ancient cats suggests that, even if the animals were domesticated outside Egypt, it was the Egyptians who turned them into the lovable fur balls we know today. It's even possible they domesticated cats a second time.

"It's a very nice piece of work," says Salima Ikram, an expert on ancient Egyptian animals and cat mummies at American University in Cairo. The idea that the Egyptians helped shape the modern cat, she says, "makes perfect sense."

The study, published in Nature Ecology & Evolution, has its roots in an ancient graveyard on the west bank of the Nile River in southern Egypt. In 2008, archaeozoologist Wim Van Neer of the Royal Belgian Institute of Natural Sciences in Brussels unearthed the remains of six cats—a male, a female, and four kittens—that appear to have been cared for by people nearly 6000 years ago. Although younger than the Cyprus cat, the discovery made Van Neer wonder whether prehistoric Egyptians could have independently domesticated the modern feline. "Scientists more or less forgot about Egypt after the Cyprus find," he says.

He gathered hundreds of cat specimens—bones, teeth, and mummies from across Africa, Europe, and the Middle East dating from about 7000 B.C.E. to the 19th century C.E. Then, he teamed up with more than two dozen researchers who drilled into the remains for mitochondrial DNA, genetic material inherited solely from the mother and found in the cell's energy-generating machinery. In 2007, other researchers had analyzed the DNA of modern cats to show that all living domestic cats trace their ancestry to the Near Eastern wildcat (Felis silvestris lybica)—a small, sandy-colored feline that looks like a Mackerel tabby. This subspecies contains felines with five unique genetic signatures in their mitochondrial DNA. "We mapped what we knew about the age and location of our ancient cats onto these signatures to figure out how the earliest cats spread out over time," says University of Oslo postdoc Claudio Ottoni, who carried out the genetic analysis in the new study.

Two waves of cats

An ancient exodus of cats from both Turkey and Egypt may have given us the modern cat.

Credits: (Graphic) A. KItterman/Science; (Data) C. Ottoni et al., Nature Ecology & Evolution (2017)

The world's first cats all appear to sport the same lybica subtype, mitochondrial type A. This genetic signature pops up at least 9000 years ago in what is now Turkey, the team reports today in Nature Ecology & Evolution. Archaeologists think that, perhaps about 10,000 years ago, wildcats in this region—with a southern coast just a few dozen kilometers from Cyprus—slunk into early farming villages to hunt rodents and eventually self-domesticated into modern cats. By 6500 years ago, these type A cats began appearing in southeastern Europe, the team found, possibly following migrating farmers. After that, cats infiltrated the rest of Europe, Africa, and Asia.

But that's only half the story. Most of the Egyptian cat mummies sport a different lybica subtype, type C, which first appears in the team's samples around 800 B.C.E. (It's possible that the type C cat could have been living in Egypt much earlier—the early graveyard study didn't yield any usable DNA.) Cats with this genetic signature appear to have been incredibly popular: By the fifth century C.E., they spread through Europe and the Mediterranean. And during the first millennium C.E., they came to outnumber type A cats two to one in places like western Turkey.

The ancient Egyptians may have been responsible for this popularity. "The Egyptians were the first people to have the resources to do everything bigger and better," says Carlos Driscoll, the World Wildlife Fund chair in conservation genetics at the Wildlife Institute of India in Dehradun, who led the 2007 study. That ability may have extended to breeding cats. As the Egyptians bred more and more felines, Driscoll speculates, they would have selected for the ones that were easiest to have around—more social and less territorial than their predecessors. "They turbocharged the tameness process."

Egypt's art reflects this dramatic transformation. The earliest representations of cats depict a working animal, like the rat hunter in the limestone tomb. But over the centuries the felines begin to appear in more domestic contexts, hunting birds with people, wearing collars, and—by 1500 B.C.E.—sitting under chairs at the dinner table. "They go from being a slaughterer of mice to a couch potato," says Eva Maria-Geigl, an evolutionary geneticist who oversaw the study with molecular biologist Thierry Grange, both at the Jacques Monod Institute in Paris. 

Still, it's unclear where these type C cats came from in the first place. Egyptian wildcats may carry this genetic signature, so type A cats from Turkey may have made their way to Egypt and mated with them. Or the ancient Egyptians may have independently domesticated cats from local type C wildcats.

Today's blotched tabbies (left)—like all cats—are descended from the Near Eastern wildcat (right).

(Left to right): © Ardea/Labat, Jean Michel/Animals Animals; © Lacz, Gerard/Animals Animals

Ikram says a dual domestication makes sense, as other animals—including dogs and pigs—may also have been domesticated more than once. But Driscoll is skeptical, noting that many plants and animals in Egypt originally came from Turkey and the rest of the Near East. "There's no reason to believe an independent domestication in Egypt."

Either way, type A and type C cats eventually intermingled in Europe and beyond. Today's cats are likely a blend of both Turkish and Egyptian cats.

And they underwent another dramatic transformation: A separate analysis of the genes for coat color showed that the coat pattern of cats—which had gone unchanged from the striped sandy appearance of its wildcat ancestors for thousands of years—began to vary, with a blotched tabby look appearing around the 14th century C.E. Dogs and horses changed coat patterns much earlier in their domestication, suggesting that when it came to cats, people were more interested in how they acted than in how they looked. "The only thing they had to do was to get better at living with people," Driscoll says. "And this paper gives clues to how that happened."

In the meantime, Van Neer still hopes to find out whether the Egyptians independently domesticated cats. He's already begun traveling to museums in Vienna, searching their collections for ancient cat mummies and DNA that may fill in the missing history of man's most mysterious friend.

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DOI: 10.1126/science.aan6984

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