CBS Local– After taking an extensive look at cat DNA dating over the last 9,000 years, researchers have concluded that humans did not domesticate cats: cats domesticated cats.

The study, published in Nature Ecology & Evolution, analyzed DNA including ancient Romanian cat remains, Egyptian cat mummies, and modern African wildcat specimens and found that cats lived alongside humans for thousands of years before moving in as house guests.

On top of that, their DNA hasn’t even changed much since humans brought them into their homes.

According to the researchers, this natural domestication occurred because mice and rats were found near human crops, thus leading the cats there and forcing interaction with humans.

“This is probably how the first encounter between humans and cats occurred,” said Claudio Ottoni, study coauthor, via National Geographic. “It’s not that humans took some cats and put them inside cages.”

The researchers figure that’s why it was so easy to render cats as pets: because they already did the hard work themselves.

“I think that there was no need to subject cats to such a selection process since it was not necessary to change them,” said Eva-Maria Geigle, coauthor and evolutionary geneticist. “They were perfect as they were.”

There are currently 74 million cats living in American homes in 2017.

“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,” Ottoni says. “I think studying more about this species is going to open up even more about the domestication process.”