May 3, 2010 | 31
Let me tell you a little story. When I was born my parents had two cats. One was named Garfield. The other…well, I don’t remember what the other one was called. Not long after I was born, and little Jason was coughing up furballs, the doctors informed the parents that their little bundle of skin and hair was allergic to cats. It was then that teams were picked and lines were drawn. It was me or the cats. Luckily, the parents decided to keep me, and lose the cats. Imagine how much it would have sucked if they decided to keep the cats and lose me. I imagine if my younger brother had actually been my OLDER brother, he might have lobbied for the cats.
And despite losing the battle of who got to live with the Mommy and Daddy Goldman, I think the cats are still trying to win the war. The thing is, I’d like to make peace with the cats. But every time I go near a cat, my eyes water, my throat gets all scratchy, I start sneezing. It’s really pretty unpleasant. I once worked at a beautiful conference center near Los Angeles. And some very kind person had decided to donate their used couches to the institute. The couches were very comfortable, and so I decided to take a nap on one of them, one day. Within minutes, the all too familiar eye-watering and throat-scratching began. And I thought to myself: “these people had cats.” How thoughtless of them to have donated their couches without at least having them cleaned. Or at least a minimal vacuuming. And then, I thought to myself: “evil cats probably orchestrated the whole thing!”
So, dear reader, it’s not that I think cats are bad, per se. It’s that cats have decided to wage holy war on me, for ousting them from their former place of reverence. And that is seriously bad times.
But because I love my readers more than I loathe cats, I set out today to learn some things about cat cognition. I spent two hours at a cafe (with poor service, good coffee, and free wifi) crawling through PubMed, Google Scholar, JSTOR, Web of Science…to no avail! And I think the reason I wasn’t able to find very much on cat cognition is because…there aren’t very many people studying cat cognition in the first place! Sure, I found a random study here and there, but nothing particularly interesting. No titles or abstracts that made me think “wow, this is really interesting.” No extended lines of research.
And that got me thinking. Why were cats domesticated in the first place? And how?
We have some pretty good information on the domestication of dogs, and some really convincing hypotheses for how dogs carved a social niche for themselves in human culture. Decades of work on domesticated silver foxes in Russia have provided really important and interesting evidence that the many differences observed between dogs and wolves can be traced to a simple breeding rule: individuals that are not scared of or aggressive towards humans get to breed. As I wrote before (at the old wordpress blog):
These experimental foxes, which were bred on a single selection criteria, displayed behavioral, physiological, and morphological (e.g. physical/visible) characteristics that were not found in the control foxes, or in some cases, such characteristics were displayed with far higher frequency in the experimental group.
Behavioral changes: The experimental foxes were more eager to hang out with humans, whimpered to attract attention, and sniffed and licked their caretakers. They wagged their tails when they were happy or excited. Does that sound like your pet dog at all? Further, they had reduced fear responses to novel items or situations, and had enhanced exploratory behavior in unfamiliar situations.
Morphological changes: These changes were perhaps the most surprising. A much higher frequency of experimental foxes had floppy ears, short or curly tails, extended reproductive seasons, changes in fur coloration, and changes in the shape of their skulls, jaws, and teeth. They also lost their “musky fox smell.”
Physiological changes: The first change detected was in the (hypothalamic-)piuitary-adrenal axis. This system is responsible for the control of adrenaline, among other things. Adrenaline is one hormone that is produced in response to stress, and controls fear-related responses. The experimental foxes had significantly lower adrenaline levels than their control-group cousins. The researchers hypothesized that foxes that are not afraid of humans are going to produce less adrenaline around them. This explains the foxes’ tameness, but it doesn’t account for their changed fur coloration patterns. The scientists theorized that adrenaline shares a biochemical pathway with melanin, which controls pigment production in fur.
And so it was that selecting for a single behavioral characteristic – tameness (or, put another way, selecting against fear and aggression) – resulted in changes not only in behavior, but also in correlated and unselected physical and physiological changes.
These results have led to speculation that similar models could account for the superior behavioral and cognitive traits (and physical and physiological differences) of domestic dogs over their wolf ancestors.
In a 2007 Science paper, Carlos A. Driscoll and colleagues analyzed the mitochondrial DNA of 979 domestic cats and their wild cat cousins: Felis silvestris silvestris (European wildcat), F. s. lybica (Near Eastern wildcat), F. s. ornata (central Asian wildcat), F. s. cafra (southern African wildcat), and F. s. bieti (Chinese desert cat). They found that each wild group constituted a sub-species of Felis silvestris.
They also found that cats were probably initially domesticated in the Near East, around the time that agriculture began in the Fertile Crescent. Mitochondrial genetic analyses showed that domestic cats are likely descended from five mother cats from this region, whose descendants were transported across the world by humans. The earliest evidence of cat-human interaction comes from archaeological remains in Cyprus dated to around 9500 years ago. This is somewhat later than the first evidence of dog-human interaction: the jawbone of a domestic dog was found in a late Paleolithic grave in Germany, and dated to around 14 thousand years ago. And there is the site at Ein Mallaha in Northern Israel where an elderly human and a 4-5 month old puppy were buried together, 10- to 12-thousand years ago.
So dogs were domesticated on the basis of their ability to socially engage with humans. One might expect that similar processes are responsible for observed differences between domesticated cats and their wild cat ancestors. And, indeed, domesticated cats are tamer compared to their wild cat ancestors, and also show diversity in coloration, as do dogs. One important difference between domesticated cats and all other domesticated species is that domesticated cats are not neotenous (literally, baby-like). All other animals that have been successfully domesticated show physical features similar to human babies – proportionally larger heads, bigger wider eyes, larger foreheads. Since human adults innately respond to those characteristics in human babies, it makes sense that domesticated animals would share some of those characteristics. Animals that showed those physical characteristics would be more likely to receive care and attention from humans than those that did not have those baby-like features. But this is not the case with cats. The limited research that has been done on human-cat interaction has shown that cats do not readily socially engage with humans, unlike dogs, primates, sometimes horses, and even dolphins and whales (to some extent) and other marine mammals.
For example, a 2005 study by A