If you’ve ever lived with a cat, you know they’re often an enigma. That said, scientists may have solved an enduring mystery about these lovable felines—with answers that could narrow down when cats first hopped onto humanity’s lap.
A large team of researchers examined the DNA of well-preserved cats located near human sites stretching back over 10,000 years ago. The oldest specimens weren’t closely related to the cats we call pets today, they found, while the lineage that gave rise to domestic cats may have only reached Europe 2,000 years ago. The findings rebuff a prevailing theory about when cats first became domesticated, but also raise more questions about how it truly occurred.
“The new study makes a very strong case that domestic cats didn’t arrive in Europe until the last few thousand years,” Jonathan Losos, an evolutionary biologist at Washington University in St. Louis who was not affiliated with the study, told Gizmodo.
The confusing origin of the cat
The domestic cat (Felis catus) is descended from the still-existing African wildcat (Felis lybica).
Today’s cats are physically and behaviorally very similar to their ancestors, in contrast to dogs, which can act and look quite different from their wolf relatives. Some of this difference comes down to the length of time we’ve spent with these animals, respectively, since dogs were domesticated much earlier in our history, likely around 20,000 years ago. But part of it also has to do with the nature of our relationship with these animals.
Very early on, people deliberately bred dogs to carry out various functions, whereas the earliest cats formed more of a mutually beneficial arrangement with humans, eating nearby rodents and pests while evolving slightly to better tolerate our presence and eventually become our adorable companions. Given that, it’s no surprise that many scientists consider cats semi-domesticated, or rather, that cats basically domesticated themselves.
Since cats haven’t changed much physically compared to their wild ancestors, it’s been hard for scientists to pin down when they first became domesticated, and that’s led to competing theories over their origins.
One theory argues that domestication began around 10,000 years ago in the Levant, a region of West Asia along the Eastern Mediterranean. A key piece of evidence for this hypothesis has been the relatively recent discovery of cat bones seemingly buried alongside a person at an archaeological site located in what’s now Cyprus. Other evidence has suggested that Neolithic farmers from Anatolia, the peninsula that covers most of modern Turkey, then migrated and first introduced domestic cats to Europe around 6,000 years ago.
The more traditional hypothesis holds that cat domestication really only took off in ancient Egypt around 4,000 years ago, a period of time when cats were clearly venerated as the superior beings we know them to be, and spread from there.
A genetic excavation
To help settle this catty debate, the researchers used ancient DNA and analyzed it with relatively new genetic sequencing techniques.
“Ancient DNA works as a time machine and can be used to track changes associated with domestication across time and help to pinpoint the origins of domestic species and their movements mediated by humans,” study authors Claudio Ottoni and Marco De Martino told Gizmodo in an email. “Furthermore, novel sequencing technologies make it possible to analyze full genome data even in ancient samples.”
The team reconstructed the genomes of 70 ancient cats collected from samples in North Africa, Europe, and Anatolia. These cats dated between the 9th century BCE and the 19th century CE. They also analyzed the genomes of modern domestic cats and wildcats to create an updated family tree of sorts.
Their genetic excavation revealed several things.
For starters, today’s cats are more closely related to wildcats from North Africa than wildcats from the Levant. Secondly, the earliest samples of ancestral domestic cats found in Europe only dated back around 2,000 years ago, whereas older cat samples in Europe and Turkey were genetically European wildcats, or Felis silvestris. These populations may have bred in the past with African wildcats, but long before actual domestic cats would have been in the area.
Though humans may have interacted with and even tried to tame wildcats several times in our history, the team’s research suggests the journey toward true cat domestication did not start in the Levant 10,000 years ago, and that it took much longer than assumed for our cats’ direct ancestors to reach Europe (and from there, the world).
“Our findings challenge the commonly held view of a Neolithic introduction of domestic cats to Europe, instead placing their arrival several millennia later,” the authors wrote in their paper, published Thursday in Science.
The researchers also appeared to clarify some confusion about wildcats living on the island of Sardinia (off Italy).
They found that both ancient and modern Sardinian cats are more closely related to North African wildcats than domestic cats. That suggests that people brought over a distinct population of wildcats to the island around 2,200 years ago, separate from the larger introduction of ancestral domestic cats to Europe; that would also mean that Sardinian cats aren’t the feral descendants of domestic cats, as is widely believed currently.
Furry mysteries left to solve
Though the team’s findings look robust, it’s certainly possible that other researchers may decide to contest them. And they definitely haven’t figured out everything about the earliest days of the domestic cat.
Losos notes, for instance, that while genetic evidence seems to place the European introduction of cats to around 2,000 years ago, archaeological artifacts indicate that it might be closer to 3,000 years.
Another issue is that while we have plenty of preserved ancient Egyptian cat mummies, it’s historically been hard to recover viable DNA from these sorts of samples, and there aren’t many other kinds of cat remains from that region and time. As such, we’re still in the dark as to exactly when and how the first ancestral housecats made their transition to domestication.
“The big remaining question is when domestication occurred; that is, when the domestic cat, Felis catus, evolved from its ancestor, the North African wildcat,” said Losos, who authored an accompanying commentary on the new study. “What is needed to answer that question is DNA from north African, middle eastern and Turkish felines that lived more than two thousand years ago.”
This current study is part of an ongoing project, Project Felix, that aims to trace back the origins of the domestic cat. And the researchers are planning to dig even deeper into the distant past of our furry felines.
“Our objective now is to analyze ancient samples from archaeological sites in Africa, including Egyptian mummies from the Pharaonic period,” Ottoni and De Martino said.
However cats became humanity’s companions—or overseers, depending on your perspective—it’s undoubtedly a relationship that continues to be a win-win for both species (but especially people).
