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Cats Conquered Laps and Hearts More Than Once, DNA Study Shows

Cats conquered our hearts and our laps more than once, a new genetic study shows.

DNA evidence suggests cats were domesticated several times, earning their keep around grain stores and traveling the world as vital crew members in the holds of ships.

Image: An Egyptian cat mummy
An Egyptian cat mummy. Daniel Simon / Gamma-Rapho via Getty Images file

The remains of cats have been found mummified in Egypt, in Viking graves and in various sites in the Mediterranean.

The research team, led by Claudio Ottoni of the University of Leuven, in Belgium, teased DNA out of the remains of 209 ancient cats dating back as far as 8,500 years ago.

They included remains found in Bulgaria and Romania dating back to 6,000 years ago; ancient Egyptian mummy samples; claws, skin and bone from Spain, Belgium, France, Turkey, Lebanon, Iran, and from Kenya, Tanzania and Angola.

Related: Researchers Map the Dog's Family Tree

They looked specifically at mitochondrial DNA, which females pass to their children with only a few genetic changes. Mutations in the DNA can be used to date it and to track ancestry.

They found two broad families of domesticated cats, one coming roughly out of South Asia, and the second coming from the Mediterranean. Nowadays, they’re all so mixed as to look genetically identical, but the ancient evidence shows wild cats were domesticated at least twice, the team wrote in the journal Nature Ecology & Evolution.

Both lineages make up the subspecies Felis silvestris lybica, but the DNA shows domestic kitties interbred, and still do, with wildcats in Europe, Asia and Africa.

The southwest Asian line of cats made its way into Europe by 4400 BC, they report.

Image: An Egyptian mummy of a cat from the Louvre's collection
An Egyptian mummy of a cat from the Louvre's collection. CM Dixon / Print Collector - Getty Images file

A separate lineage accounts for the felines shown in Egyptian tomb paintings and that were mummified and buried alongside their presumably adoring human companions.

Related: Kitten Burial Showed Egyptians Loved Fluff 6,000 Years Ago

The reasons people carried them around and protected them are obvious.

“While it is nowadays one of the most cherished companion animals in the Western world, for ancient societies barn cats, village cats and ships’ cats provided critical protection against vermin, especially rodent pests responsible for economic loss and disease,” the researchers wrote.

“The increasing popularity of cats among Mediterranean cultures and particularly their usefulness on ships infested with rodents and other pests presumably triggered their dispersal across the Mediterranean.”

Cats have not been intensively bred into different body shapes, sizes and colors in the same way that dogs have, and the researchers found evidence that any breeding for looks came late — with the appearance of the blotched tabby marking pattern in the 1300s in Turkey.

The Felis silvestris species of cat naturally has the narrow stripes known as the mackerel tabby marking. Wide, blotchy stripes are caused by a single genetic mutation that showed up later.

It was temperament more than looks that may have made one strain of cats more beloved than another, the researchers said.

Related: Ancient Burial Shows Human-Cat Links Goes Back Millennia

"The Egyptian cat must have been very popular," they wrote. Its DNA had spread widely by the year 1000.

"This suggests that the Egyptian cat had properties that made it attractive to humans,” they added. “As the most pronounced genetic changes that distinguish wild and domestic cats are apparently linked to behavior, it is tempting to speculate that the success of the Egyptian cat is underlain by changes in its sociability and tameness.”

The DNA and historic evidence suggest the Romans carried pet cats further into Europe with them.

"In medieval times it was compulsory for seafarers to have cats onboard their ships, leading to their dispersal across routes of trade and warfare," the team wrote.

“This evidence explains, for example, the presence of the Egyptian lineage ... at the Viking port of Ralswiek (7–11th century AD)," they wrote.

“Spread of the black rat and house mouse by sea routes as early as the Iron age, documented by zooarchaeological and genetic data, probably also encouraged cat dispersal for the control of these new pests.”

There's no indication in the DNA of when the cat-human relationship changed, and humans became the servants of cats. "Cat domestication was a complex, long-term process," the researchers concluded.