Dogs are used far more often than cats in the lab for research of important areas like genetics and cancers. Are there good scientific reasons for that, or are there cultural biases at work? Photo Credit: Kim Murton/The New York Times
Recently, someone 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. But I figured I should do some reporting, so I emailed Elinor Karlsson at the Broad Institute and the University of Massachusetts, USA. 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 behaviour. 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 asked Elinor whether there was indeed more research on dogs than cats, and if so, why? "Oooh, that is an interesting question!" she wrote back. "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."
A good reason
Better models than cancers in dogs, that is. Dogs get many of the same cancers as humans, but in dogs the risk for these often varies by breed, narrowing the target when looking for the cause of a disease. Furthermore, said Elinor, cat behaviour gets no respect. "Non-cat people tend to laugh at the idea of studying behavioural genetics in cats, and the animal training world complains that people tend to dismiss cats as untrainable," she said.
Cats, of course, can be trained just as any animal can. Elinor unwittingly trained her cat to hop up on the counter when she opened the door of a cabinet containing goodies. Elinor 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 organisation of scientific meetings, Elinor 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.
Next, I called one of the main people responsible for the recent cat genome Elinor was talking about, Leslie Lyons at the University of Missouri, USA. 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." 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 said social reasons having to do with popular attitudes towards cats spill over into the realm of research. Cat lovers are not as interested in fancy breeds - yet. Cats could be bred in many different shapes and sizes like dogs, she said, if there were interest. 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."
And now the numbers: a search of Pub Med, a database that includes most biomedical journals, yielded 1,39,858 results for cats and 3,28,781 for dogs. These are simple searches, of course, and don't say much about the kind of research that was undertaken. Also, a colleague raised a question that didn't occur to a single expert I interviewed. "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?
The New York Times