Cosmo: Hey, Dr. Universe.
Dr. U: Hey, Cosmo.
Cosmo: Why don’t cats play games in the savannah?
Dr. U: I’m not sure.
Cosmo: There’s too many cheat-ahs
Dr. U: Hey friends, I’m Dr. Universe.
Cosmo: And I’m Cosmo.
Dr. U: And if you’re anything like us, you’ve got lots of big questions about our world. Today we’re answering a question sent in by a kid just like you.
Cosmo: Morgan wants to know: How did big cats change into house cats?
Dr. U: It turns out that house cats share about 95% of our DNA with big cats like tigers and lions. All cats belong to one big family: Felidae.
Cosmo: Awwww, we’re friends and family, Dr. Universe!
Dr. U: Definitely. And our family is complicated. House cats like us are the result of evolution and domestication.
In any group of living things, some individuals have traits that help them thrive. They’re more likely to survive and reproduce—and pass those traits on to their babies. That’s called natural selection.
Over time, the group changes. Super useful traits become more common. That long-term change is called evolution. Eventually, a group may change so much that it becomes a whole new species.
That’s what happened with house cats. Their ancestors changed over time until they were a new species. But those ancestors weren’t big cats.
Cosmo: They weren’t lions or tigers or saber-toothed cats?
Dr. Universe: nope
Cosmo: Awww, man. Those guys are cool.
Dr. Universe: All cats—lions, tigers, saber-toothed cats, house cats like us—have a common ancestor. We’re like distant cousins to each other. We share an ancient relative.
There were two important splits in the cat family tree.
About 20 million years ago, the saber-toothed cats branched off from the ancestors of modern cats.
Cosmo: I’m sad to see them go.
Dr. Universe: Then 12 million years ago, modern cats broke into big cats and smaller cats. The big cats were the ancestors of lions and tigers. The smaller cats were the ancestors of cougars, panthers, and African wildcats.
Smaller cats have a few advantages. They need less food. Plus, they’re spry. Massive lions are successful hunters just 20% of the time. But African wildcats bring down a whopping 60% of their prey.
Those nimble African wildcats are the direct living ancestor of all house cats.
Cosmo: Oh! Ok, our ancestors are fierce!
Dr. Universe: Definitely. And then somebody else stepped in to change African wildcats into house cats like us.
Cosmo: Is it magic?
Dr. Universe: It’s humans.
Cosmo: Darn it.
Dr. Universe: What they did is artificial selection. It’s humans making choices.
Nearly 12,000 years ago, some humans changed how they lived. Instead of foraging and hunting, they settled down and began farming. They grew and stored grain, and guess who showed up to nibble on it?
Cosmo: Mice!
Dr. Universe: Yep. And then the local wildcats jumped on the opportunity—literally.
Soon, wildcats and farmers formed a partnership. The cats killed mouse pests. The humans provided an easy place to hunt.
Over time, some wildcats developed new traits that strengthened their bonds with humans. Eventually, they were so different from wildcats that they became a new species: the house cat.
Dr. Universe: Scientists can see 13 genes that separate today’s house cats from modern wildcats. They govern things like fearfulness and receptivity to food rewards.
Cosmo: So, our ancestors changed because some wildcats were friendly and liked treats?
Dr. Universe: Exactly. And because humans found them irresistible. Soon, they became besties.
The oldest physical evidence of house cats is 9,500 years old. Scientists working at a dig site in Cyprus found a grave. Inside, a human and a cat were buried together.
That’s interesting because African wildcats aren’t native to Cyprus. So, those early cats must have traveled there with their human companions. There must be artifacts of earlier cat domestication out there, waiting to be found.
Cosmo: You could say we’re a purr-fect match.
Dr. Universe: That’s all for this episode, friends.
Cosmo: Big thanks to Haden Kingrey, an anthropology doctoral student at Washington State University.
Dr. Universe: As always, if you’ve got a science question for me, you can submit it at askdruniverse.wsu.edu. That’s A S K D R U N I V E R S E dot W S U dot E D U.
