Why Scientists Love to Study Dogs (and Often Ignore Cats)

Recently someone (my boss, actually) mentioned to me that I wrote more articles about dogs than I did about cats and asked why.

My first thought, naturally, was that it had nothing to do with the fact that I have owned numerous dogs and no cats, but rather reflected the amount of research done by scientists on the animals.

After all, I’ll write about any interesting findings, and I like cats just fine, even if I am a dog person. Two of my adult children have cats, and I would hate for them to think I was paying them insufficient attention. (Hello Bailey! Hello Tawny! — Those are the cats, not the children.)

But I figured I should do some reporting, so I emailed Elinor Karlsson at the Broad Institute and the University of Massachusetts. She is a geneticist who owns three cats, but does much of her research on dogs — the perfect unbiased observer. Her research, by the way, is about dog genomes. She gets dog DNA from owners who send in their pets’ saliva samples.

The research I have been interested in and writing about involves evolution, domestication, current genetics and behavior. And the questions are of the What-is-a-dog-really? variety. Dogs and cats have also been used as laboratory animals in invasive experiments, but I wasn’t asking about which animal is more popular for those.

I had gotten to know Dr. Karlsson a bit while reporting on research she was doing on wolves. I asked her whether there was indeed more research on dogs than cats, and if so, why?

“Ooo, that is an interesting question!” she wrote back. “Way more interesting than the various grant-related emails that are filling up my inbox.

“The research has lagged behind in cats. I think they’re taken less seriously than dogs, probably to do with societal biases. I have a vet in my group who thinks that many of the cancers in cats may actually be better models for human cancer, but there has been almost no research into them.”

Better models than cancers in dogs, that is. Dogs do get many of the same cancers as humans, but in dogs the risk for these cancers often varies by breed, which narrows the target down when looking for the cause of a disease.

Furthermore, said Dr. Karlsson, cat behavior gets no respect.

“Non-cat people tend to laugh at the idea of studying behavioral genetics in cats, and the animal training world complains that people tend to dismiss cats as untrainable.”

Cats, of course, can be trained just as any animal can. Dr. Karlsson unwittingly trained her cat to hop up on the counter when she opened the door of a cabinet containing goodies.

And commerce has recognized cat trainability. There are several models of toilet training kits to teach cats to use human toilets. If such kits exist for dogs, I couldn’t find them. Not even for Bichon frises.

And as to the cancers, Dr. Karlsson said Kate Megquier, a veterinarian working on a Ph.D. at the Broad Institute in cancer genomics thought cat cancers deserved more attention.

Dr. Megquier said “I’ve been studying a lot of the dog cancers,” but that there are reasons studying certain naturally occurring cancers in cats could be valuable.

They get a lot of cancers called lymphomas, she said, and “they certainly have something to teach us about lymphomas.” They also get oral cancers similar to ones humans get and it’s possible, she said, that these might be related to environmental toxins they pick up while grooming themselves.

Investigating that possibility “could give us some insight into these cancers,” she said, helping pets and people. Dr. Megquier likes dogs, but is, by her own account, “definitely a cat person.”

Dr. Karlsson said that there are good reasons dogs are studied so intensively. There are many more dog breeds — about 400 compared to about 40 cat breeds. That means more genetic diversity, and better tools for studying genomes.

She did note, however, that a new reference cat genome is more detailed than the most recent dog genome.

“We’re all hugely jealous of it, and had to put up with lots of teasing from the cat geneticists at the meeting I was at last week,” she said.

Cultural attitudes toward pets creep into research even in the organization of scientific meetings, Dr. Karlsson pointed out. Putting the two animals together as the subject of a meeting is more related to their status as the iconic human pets rather than biological similarity.

My next email was to Elaine Ostrander, at the National Institutes of Health, who both owns pet dogs and studies dog genetics.

Her lab has identified eight genes that play a big role in determining dog size, the first being one important for making dogs small. The lab has also identified cancer genes shared by human beings and dogs. In particular, her lab identified a genetic cause of a kidney disease common to German shepherds before the same gene was shown to cause the same cancer in people.

Dr. Ostrander replied to my email by noting the attraction to science of the many different dog breeds and the vast range in dog size and shape. Some of the genes that affect growth, she said, affect “diseases of growth gone awry, like cancer.”

In addition, she wrote, “dogs have undergone this really striking bottleneck during domestication,” in which a few ancestral wolves gave rise to all domestic dogs. Later on Victorians produced many breeds that have even narrower bottlenecks, with much inbreeding.

Domestication, she said, has “happened in an amazingly short period of time and we don’t understand all the genetics associated with it. It remains one of the most interesting and challenging questions in biology.”

Some dogs suffer from behavioral problems that look similar to human problems like Obsessive Compulsive Disorder. Those similarities, Dr. Ostrander said, provide “a great avenue for learning more about ourselves.”

That pretty much stated the case for dogs, I thought. Next, I called one of the main people responsible for the recent cat genome Dr. Karlsson was talking about, Leslie Lyons at the University of Missouri.

I asked her about there being more research on dogs than cats.

“That’s absolutely true,” she said, “for several different reasons.”

She agreed that the “the dog is a great model for cancers,” she said. It’s also true they have been domesticated longer than cats, and have more breeds, thus having a greater potential for studying inherited diseases.

But she also said there are social reasons having to do with popular attitudes toward cats that spill over into the realm of research. She said cat lovers are not as interested as dog lovers in fancy breeds — yet. Cats could be bred in many different shapes and sizes like dogs, she said, if there were interest. “We could have a Chihuahua cat and a Great Dane cat,” although, she said, “I think that would be a little dangerous.”

She said research funds are much harder to obtain for cats, even though cats are superior to other animals for studying some diseases, like polycystic kidney disease, or PKD. “Let’s put them in drug trials. We could fix the cats and we could fix humans.” Dr. Lyons keeps cats as pets and did mention, in an offhand way, during our conversation the common observation that “Cats rule, dogs drool.”

I also called Fiona Marshall, a bioarchaeologist at Washington University in St. Louis. We had spoken a while ago for an article I did on donkeys. The domestication of donkeys is only one of her areas of interest. She also studies African cats and cat domestication and was one of the authors of a paper several years ago that dated the first evidence of domestic cats to a 5,300-year-old site in China.

She said that cats are rarer than dogs in archaeological sites, partly because they’re solitary and they don’t seem to have been eaten as much by ancient humans.

“If they’re not eaten, you don’t find them in waste piles,” she said.

“I also think that there is a bias as a result of medieval to later European views of cats,” she said. “Cats were considered to be bad animals because they didn’t do what humans said.” And yet, that is the source of their appeal now for many people. Dr. Marshall herself has pet cats.

And now the numbers: A search of Pub Med, a database that includes most biomedical journals, yielded 139,858 results for cats and 328,781 results for dogs. Google scholar results were 1,670,000 for cats and 2,850,000 for dogs. These are simple searches, of course, and don’t say much about the kind of research that was undertaken.

As for journalism, my searches on the news database Nexis for dogs and cats kept returning more than 3,000 hits, which my screen warned me would take a long time to retrieve. So I settled for searches of “dog genome” and “cat genome.” The result, 20 for dogs, 6 for cats. The dog genome was sequenced before the cat genome.

I would caution against concluding anything based on this haphazard browsing other than that the results do back up the researchers’ sense that there’s more research on dogs.

Also, a colleague raised a question that didn’t occur to a single expert I interviewed, which shows that devotion to science can sometimes limit your point of view.

“Is it possible,” my friend, who has had both cats and dogs, asked, “that there are more dog studies because the cats won’t consent?”

Of course. Why didn’t I think of that?

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