First domestic cats decided to be near humans

WASHINGTON – Your hunch is correct. Your cat decided to live with you, not the other way around. The sad truth is, it may not be a final decision.

But don’t take this feline diffidence personally. It runs in the family. And it goes back a long way – about 12,000 years, actually.

Those are among the inescapable conclusions of a genetic study of the origins of the domestic cat, being published today in the journal Science.

The findings, drawn from the analysis of nearly a thousand cats around the world, suggest that the ancestors of today’s tabbies, Persians and Siamese wandered into Near Eastern settlements at the dawn of agriculture. They were looking for food, not friendship.

They found what they were seeking in the form of rodents feeding on stored grain. They stayed for 12 millennia, although not without wandering off now and again to consort with their wild cousins.

“It is a story about one of the more important biological experiments ever undertaken,” said Stephen O’Brien, a molecular geneticist at the National Cancer Institute’s laboratory in Frederick, Md., and one of the supervisors of the project.

“We think what happened is that cats sort of domesticated themselves,” said Carlos Driscoll, the University of Oxford graduate student who did the work, which required him, among other things, to befriend feral cats on the Mongolian steppes.

There are today 37 species in the family Felidae, ranging from lions through ocelots down to little Mittens. All domestic cats are descended from the species Felis sylvestris (“cat of the woods”), which goes by the common name “wildcat.”

The species is indigenous to Europe, the Middle East and East Asia. The New World, Japan and Oceania, lack wildcats. Their closest counterpart in North America is the lynx.

Driscoll and his collaborators, who included Oxford zoologist David Macdonald, took blood samples and ear punch biopsies from all wildcat subspecies, and from fancy-breed cats, ordinary pet cats, and feral cats. They analyzed two different kinds of genetic fingerprints.

Both fingerprints showed that domesticated cats all around the world are most closely related to the wildcat subspecies (called lybica) that lives in the Near East.

One might think that people in each region would have domesticated their local wildcats. In that case, European pet cats today would genetically most closely resemble European wildcats and Chinese cats would be descended from East Asian wildcats. But that isn’t the case.

Why not?

Genetics can’t answer the question, but history and archaeology can provide a good guess.

Large-scale grain agriculture began in the Near East’s “Fertile Crescent.” With the storage of surplus grain came mice, which fed on it and contaminated it.

Settled farming communities with dense rodent populations were a new habitat. Wildcats came out of the woods and grasslands to exploit it. They may have lived close to man – but not petting-close – for centuries.

Eventually, though, natural selection favored individual animals whose genetic makeup by chance made them tolerant of human contact. Such behavior provided them with them with things – a night indoors, the occasional bowl of milk – that allowed them to out-compete their scaredy-cat relatives in town.

For people, it was a great package – agriculture, food surplus (and all the civilizing effects that came with it), with domesticated cats thrown in to protect the wealth by eating the mice.

“When that technology was transferred to other cultures, so were the cats,” said Robert Wayne, an evolutionary biologist at the University of California in Los Angeles. Therein lies the reason other cultures didn’t domesticate local wildcats, he said. “Why reinvent the wheel?”

This is not true with other acts of animal domestication.

Genetic studies have shown that cattle, goats, sheep, pigs and water buffalo were all domesticated at least twice in entirely independent events. With horses, it happened many times.

The consequence of one other feline behavior – the average cat’s uncertainty about whether it wants to be indoors or out – was also written in the genes Driscoll studied.

He found that a significant fraction of wildcats in Europe, southern Africa and Central Asia were hybrids. They carried genetic evidence of having tomcatted around from time to time with their domesticated relatives.