Before spreading on the Internet, cats spread like wildfire around the world thanks to their ability to keep rodents away from the harvest. But the dynamics of their "dispersion" from the Fertile Crescent (the Middle East, around the fertile valleys of the Nile, the Jordan, the Tigris and the Euphrates) to the rest of the world were not yet known.

Now the largest study of the DNA of ancient cats makes it clear how their friendship with man developed.

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Carpet research. Eva-Maria Geigl, evolutionary geneticist of the Institut Jacques Monod in Paris, analyzed the mitochondrial DNA (ie transmitted on the maternal line) of the remains of 209 cats taken from more than 30 archaeological sites in Europe, Africa and the Middle East, and lived between 15 thousand years ago and 1700.

The analysis added some firm points, such as the attested presence of a cat in the tomb of a man who lived in Cyprus 9, 500 years ago (ie at the dawn of the agricultural revolution) and the evidence of domestication - and mummification - of cats in Egypt starting 6, 000 years ago.

The guardians of the barn. He thus established that domestic mici populations grew in two successive waves. The cats of the Middle East expanded towards the eastern Mediterranean together with the first agricultural communities, starting from 12 thousand years ago. In these contexts the felines were necessary to keep mice away from provisions.

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By sea. The second wave, thousands of years later, saw cats originating in Egypt rapidly expanding in Africa and Eurasia, thanks to the development of commercial and naval traffic. The same line of mitochondrial DNA found in Egyptian cat mummies dating from the 4th century BC to the 4th century AD was found in feline remains in Bulgaria, Turkey and sub-Saharan Africa from the same period.

Viking cats. But perhaps the most surprising fact is the discovery that the Viking navigators had to keep the cats in their holds to protect the provisions from the mice, taking them to northern Europe. The same mitochondrial DNA line was also found in a Viking site in northern Germany from the 8th to 9th centuries.

Now scientists also hope to be able to analyze nuclear DNA (50% inherited from the father and 50% from the mother) to complete the migration picture.