Investigating Cat Behavior Through Genetics

FLORA LICHTMAN: This is Science Friday. I’m Flora Lichtman. Calling all cat people, this one’s for you. Despite humans long history of welcoming felines into our homes and our bodegas, cat research lags far behind that of dogs. Now scientists are working to close the cat gap by enlisting cat caretakers from across the country to submit a tuft of fur and answer a few questions about their felines appearance, personality, and behaviors.

Here to tell us all about this new project and what we do and don’t know about cat genetics is my guest, Dr. Elinor Karlsson, Chief Scientific Officer at Darwin’s Ark, a Professor at UMass Chan Medical School, and Director of the Vertebrate Genomics Group at the Broad Institute of MIT and Harvard Universities. Elinor, welcome back to Science Friday.

ELINOR KARLSSON: Thank you very much for having me.

FLORA LICHTMAN: Why is there more research about dogs than cats?

ELINOR KARLSSON: That’s a really good question. I could come up with a lot of reasons why, scientifically, we focused more on dog genetics early on. There are a lot of advantages to the breeds that we have in dogs, especially when genomics was very difficult in the beginning. But I think also, people didn’t think for some reason that cats had as much to study, which I think anybody who lives with a cat will know that they’re nothing, if not full of questions.

FLORA LICHTMAN: The cat people are pounding their fists right now against their tables. I mean, I’m like, are cats like the women of scientific research? Like, ignored, basically?

ELINOR KARLSSON: It feels a little bit like that, I’ve got to say. It’s like there’s a bunch of diseases that cats get that would be fantastic models for human diseases. And so this is often why we study other species, is that there’s something we can learn from them that will also help people. And yet, despite the fact that we know that, for some reason, those studies just haven’t been done.

FLORA LICHTMAN: I mean, are cats actually better models for human disease than dogs in some cases?

ELINOR KARLSSON: They’re very complimentary in the sense that there are diseases that cats get that dogs don’t get. One of the most common diseases that cats get, that people also get is type 2 diabetes. Dogs get something that’s more like type 1 diabetes, but they don’t get type 2 diabetes. And yet, it’s this huge disease in humans as well. And so by studying cats and how this disease happens in cats, we might be able to learn something about its causes in people as well.

FLORA LICHTMAN: What are some of the big questions you’re hoping to answer with this project?

ELINOR KARLSSON: Well, I think right now the question might be, what isn’t a question. The more we dig into it, the more we’re surprised by how little we know about this animal that lives with so many of us. We’re not even really sure exactly what a cat breed is.

FLORA LICHTMAN: What do you– what?

ELINOR KARLSSON: I know. Doesn’t that seem– it’s like everybody’s like, “Well, it’s just a breed.” And you’re like, well, in dogs, a breed is this population of dogs where all the dogs in the breed are super closely related to each other, and it dates back to Victorian England, and they were selected for what they look like, et cetera, et cetera. And some cat breeds might be like that, but other cat breeds like Siamese, you might have some cats that are in the breed, but also cats where people just say, “Well, they look Siamese, and so we’re going to call them a Siamese.”

And different cat breeds or cats that people think are in different breeds come from different parts of the world? We’ve got some small studies that have suggested there’s some really interesting genetics out there that we could look at to just see how cats have moved around the world. And we just need a lot more cats enrolled in studies to be able to do that work.

FLORA LICHTMAN: So, I mean, a lot of people have Domestic Shorthair cats. That’s the breed listed on their vet records. Is that a breed?

ELINOR KARLSSON: Well, it depends on how you define a breed. I would say no. I live with three absolutely wonderful Domestic Shorthairs, which means that I adopted them at the MSPCA, and it said on their form that they were Domestic Shorthairs because they had short hair. And so it’s more a, I guess, a phenotypic definition, we would call it.

FLORA LICHTMAN: That’s interesting. I think also some, quote, “breeds,” some types of cats have different reputations. And we put out this caterwaul to our listeners for their questions about cat behaviors and traits, and we got, for once, many welcomed cat calls. And I want to play you, Joni– a call from Joni in Maryland who bristled at the stereotype that orange cats are menaces.

AUDIENCE: Are you kidding? Orange cats are destructive meanies? No way! My cat used to greet all the children coming into the house. Any kind of neighbor. The only people he was a menace to was one really witch of an attorney, and I’ll tell you what, this gentle, beautiful cat spit at is her. And I told her to bring a bribe next time and take off the noisy shoes. She brought a bribe, and he hissed, and he went out to try to bite her. I could not believe it. So meanies? Ut uh. Only if you’re a witchy. I’ll tell you what, orange cats are outgoing behavior, and they’re fun, and I love them.

FLORA LICHTMAN: Any response for Joni?

ELINOR KARLSSON: Well, I am with Joni on this one. The first two cats that I ever had, their names were Leif and Darwin, were both orange, and they were both the best cats ever. So, yes, I do not think there’s anything to the stereotypes. And one of the things that really surprised me when we started doing this project was how many stories there are out there. How many people have told me that particular colors of fur are connected to particular personalities and behaviors.

And to me, it feels very similar to something that we’ve been also looking at in dogs, where people assign different dog breeds different behavioral characteristics. We call them breed stereotypes. And we looked at it in dogs very deeply using all of the survey data that people gave us about their dogs, and very few of them could we find a lot of support for.

And so we’re going to do the same thing in cats now. We’re going to try to get a whole lot of cats signed up. We’re going to ask their owners lots and lots of questions about their cats. And then we’ll look at whether the personality characteristics reported by people who have orange cats are any different than the personality characteristics reported by people who have other colors of cats.

FLORA LICHTMAN: I mean, that seems– like, is there a chance there would be personality traits that would be linked somehow to fur color?

ELINOR KARLSSON: I can’t, as a geneticist, see any real reason why that would be true. Color is controlled largely by changes in a few genes. And behavioral traits are usually what we call complex, meaning that they’re influenced by many, many different genes, and also by environment. So the lead scientist on our project, who’s an amazing scientist, Kasia Bryc, has actually taken a quick look at this with the number of cats that we have signed up right now, which is about 5,000 or 10,000. And we’re not seeing anything in that data set right now, but we’re going to keep looking at it because this is something that, as I said, that people keep telling me.

FLORA LICHTMAN: Well, look out for orange cats and their attention and attunement to witches. Witchy people.

ELINOR KARLSSON: Yeah, I can’t say that we ask that survey question. I’m trying to figure out a way we would phrase that, and it’s not really immediately coming to mind.

FLORA LICHTMAN: OK, while we’re on breeding, we got this very intriguing listener question.

AUDIENCE: This is a Chunk of McMinnville, Oregon, and my question for you is, why are there no miniature cats? There’s miniature almost everything else. Miniature pigs, miniature horses, miniature goats, miniature dogs. And it’d be so great if there were a small cats for apartments and things like that. If we had adult cats the size of kittens, that would be fabulous. And I just don’t understand why they’ve never successfully miniaturized cats.

FLORA LICHTMAN: Elinor?

ELINOR KARLSSON: I find this to be a really interesting question as well. And I actually looked into this a number of years ago when the same question occurred to me when I was sitting on my couch in the middle of the night. And–

FLORA LICHTMAN: Are you serious?

ELINOR KARLSSON: Yeah, no, totally. I was like, why are there not miniature cats? You would think somebody would have done this by now. I was working on dogs, and there were these teacup chihuahuas, and I was very confused by why there were not miniature cats. And the best I can come up with is that– the interesting thing about dogs is not just that genetically we can breed them to be very different sizes, but that for some reason, the dog physiology, their shape sort of works OK at all those different sizes.

I think what might be happening in cats is that people can try to breed them really small, but then they might have issues like maintaining their body temperature as kittens and things like that, and so it may not be a size that really works for them physiologically.

FLORA LICHTMAN: Hmm. What animal was the pet cat descended from? Who were– who was my cat’s ancestor?

ELINOR KARLSSON: That’s a great question. So there was actually just a couple of weeks ago some new papers came out that confirmed that the most likely origin of cats was in Egypt, and it was actually surprisingly recent. It might have been as recently as about 3,000 years ago that domestic cats became part of our world.

FLORA LICHTMAN: How does that compare to dogs?

ELINOR KARLSSON: Dogs are actually really old. Everything we’ve looked at in dogs suggests that they’re probably one of the first, if not the first, domestic species. And our best guess is probably somewhere between 15,000 and 20,000 years ago.

FLORA LICHTMAN: OK, OK. And what– and so they’re in Egypt. And what animal– what’s the animal– the wild version of–

ELINOR KARLSSON: Yeah, there’s an African wildcat that was the ancestor of all house cats, with a small caveat, which is that some cats actually have what we call admixture, which means ancestry from other species of cats. I think the most famous is probably Bengal cats, which many people own. So they have some ancestry from a different species of cats. But we’re curious to find out in pet cats how often this happens. And so that’s actually one of the things we’re going to be looking at as we build up our genetic data set.

FLORA LICHTMAN: OK, I’m looking at pictures of an African wildcat right now. And they look like just a leggier, long-legged version of a cat. Of a house cat. Like, they look very similar.

ELINOR KARLSSON: There’s also amazing amount of consistency across cats, though, too. I bet if you Google like Scottish wildcat, which was another contender for the ancestor of cats, it also looks strikingly similar to what cats look like today. It looks like their shape works pretty well for them.

FLORA LICHTMAN: Yeah. I mean, dogs, my sense– you tell me, are quite different from wolves. Have cats changed much from their wild form?

ELINOR KARLSSON: I think anybody that’s tried to live with a wildcat would probably say absolutely definitely in terms of their behavior, but possibly not as much in terms of their shape.

FLORA LICHTMAN: Hmm.

ELINOR KARLSSON: Basically, the process of dog domestication was that wolves somewhere started eating human garbage as a food resource. And so dogs actually switched from being hunters, which is what wolves are, to scavengers. They basically have evolved to eat our garbage. They have all these changes in genes related to carbohydrate processing and things like that in order to be able to survive on our garbage.

Cats chose a different evolutionary strategy, which is that they’re still hunters. They still hunt mice. They hunt the mice that live in our grain and the rodents that live on our garbage that the dogs are busy eating, but they never made that switch from being hunters to being solely scavengers the way that dogs did. And so we might not actually expect that, in terms of their hunting behavior, we’ve had as many changes as what we see in dogs.

FLORA LICHTMAN: That’s fascinating. I mean, is that a genetics thing?

ELINOR KARLSSON: Oh, totally. So in dogs, wolves have something called the predatory sequence, which is a series of behaviors that they implement in order to be able to hunt. And in dogs, that sort of all got mixed up. And the result of that was actually a lot of the different behaviors that you see in dogs today, like retrieving and herding and livestock-guarding are all different versions of what was originally the wolf sequence that they used to hunt.

In cats, you still see that hunting predatory motor pattern, as they call it. I remember Kathryn Lord, who’s the scientist in my group that knows the most about behavior, was over at my house one day. I was playing with my cats with one of these very string toys with a bird thing at the end of it– feathers at the end of it. And my cat jumped up to grab the bird, and she said, “And now she’s going to put one paw on it.”

And then my cat put one paw on it. And I was like, “Oh my God, how did that was going to happen?” She’s like, that’s just what they do. That’s their sequence. And I was like, I had no idea until that point how encoded in our DNA some of these behaviors are. But it makes sense if you think about it, because the one thing that an animal needs to be able to do is feed itself, and so it can’t really leave that up to chance.

FLORA LICHTMAN: Well, speaking of behavior sequences, here’s a strange one from another listener.

AUDIENCE: Hello, my name is Ry. I’m calling from Louisville, Kentucky. My Calico does not like it whenever I practice any of my instruments. I first started noticing this whenever I was a flutist in my marching band, anytime I would take out my flute and try to practice, she would come up to me, she would take her paw, and she would put it on the end of my flute and bring it gently down, telling me that she did not like that I was practicing. Since then, I’ve taken up banjo, and she does the exact same thing where she will physically stop me from practicing. Why does she not like my artistic endeavors?

ELINOR KARLSSON: I have absolutely no idea what’s going on there, but I will say that one of the things that I found interesting about trying to figure out how to study behavior is how important it is to separate our observation of what the cat is doing from our emotional interpretation of it. So it’s possible that the sound of the instruments, especially if it’s more high-pitched, the cat hears really well and it sounds really exciting, like birds or something. Or maybe she really doesn’t like it because it’s a really distracting noise. I have absolutely no idea. But it’s an interesting question. Could we ask people, does it bother your cat when you play music? I don’t know what the answers would be, but I’m kind of curious now.

FLORA LICHTMAN: OK. If folks want to contribute to your cat genetics project, what do they do? How can they sign up.

ELINOR KARLSSON: It’s very easy. You can go to our website. It’s called darwinsark.org and sign up there. It’s free to sign up your pet and answer all of our survey questions. We love people who answer our survey questions. We also have the option on there to send us a fur sample to do DNA sequencing. We need a donation to do that because there’s a cost associated with that. But the whole thing is an open data project, meaning that any information that we collect is going into a big data set that we’re building to share with other scientists on the theory that that’s the way to increase the amount of science that’s being done on cats very quickly.

FLORA LICHTMAN: Yeah, we got to build up the data set. I feel like we can– how many people do you want to get? What’s your goal?

ELINOR KARLSSON: For things like diabetes or kidney disease, we’re going to need much larger sample sizes for that. And so the more pets that we can get enrolled, the more complex the questions are that we’re going to be able to answer.

FLORA LICHTMAN: 1 million cats? 100,000? I’m just, like, I feel like our audience can do this. I feel like we can just– we can solve this problem–

ELINOR KARLSSON: This would be like my total dream. So, OK. So I have to give a number. I would love to have a million cats enrolled.

FLORA LICHTMAN: A million cats, OK. Where do we go? What’s the website?

ELINOR KARLSSON: Darwinsark.org.

FLORA LICHTMAN: Darwinsark.org archive.org. Elinor, thanks so much for giving us the whole kitty and caboodle on this. Appreciate it.

ELINOR KARLSSON: No problem at all. Thank you.

FLORA LICHTMAN: Dr. Elinor Karlsson, Chief Scientific Officer at Darwin’s Ark, Professor at UMass Chan Medical School, and Director of the Vertebrate Genomics Group at the Broad Institute of MIT and Harvard.

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