◄►Bookmark◄❌►▲ ▼Toggle AllToCAdd to LibraryRemove from Library • BShow CommentNext New CommentNext New Reply
Here’s Razib Khan of the Unz Review writing on recent evolution in the New York Times:
Our Cats, Ourselves
By RAZIB KHAN NOV. 24, 2014
DAVIS, Calif. — IT’S commonplace to call our cats “pets.” But anyone sharing a cat’s household can tell you that, much as we might like to choose when they eat in the morning, or when they come inside for the night, cats are only partly domesticated.
The likely ancestors of the domestic dog date from more than 30,000 years ago. But domestic cats’ forebears join us in the skeletal record only about 9,500 years ago. This difference fits our intuition about their comparative degrees of domestication: Dogs want to be “man’s best friend”; cats, not so much.
Fossils are handy snapshots of the past, but a genomic sequence is a time machine, enabling scientists to run evolutionary history backward. The initial sequence of the domestic cat was completed in 2007, but a recent study to which I contributed compared the genomes of the domestic cat and the wildcat (Felis silvestris) and sheds new light on the last 10,000 years of feline adaptations.
Domestic cats are not just wildcats that tolerate humans in exchange for regular meals. They have smaller skulls in relation to their bodies compared with wildcats, and are known to congregate in colonies. But in comparison with dogs, cats have a narrower range of variation in size and form.
Wesley C. Warren, an author of the study, notes that domestic cats have excellent hunting skills, like their wild ancestors. This, too, supports the notion that cats are only semi-domesticated.
Comparing the genomes of the wildcat and the domestic cat added much to what we had known. Michael J. Montague, the lead author, told me he’d anticipated that the two genomes would be very similar, but our study found a specific set of differences in genes involved in neuron development. This brain adaptation may explain why domestic cats are docile.
Scientists have long observed that domesticated species exhibit a suite of strikingly similar traits, from floppy ears to smaller brains, than those of their wild ancestors. Domestication may select for a few similar traits encoded by genetic changes (like smaller brains), but these may produce what we assume are secondary effects (like floppy ears).
Once they were living among us, cats didn’t need to think so much to stay alive; nor did they need such large jaws after we started feeding them our processed scraps. Hence smaller skulls. The same dynamic holds for dogs: Wolves beat dogs in general intelligence tests.
By examining patterns in our animals’ genomes, we’ve confirmed that the same sets of genes seem to be targeted again and again in evolution. As far back as Charles Darwin, domestic animals in particular have yielded insights about evolution because we know what sorts of selection pressures they were subject to. After all, it was us they were primarily adapting to.
Which brings us to the genome of one critical tame animal: ourselves, humans. The Nobel Prize-winning zoologist Konrad Z. Lorenz once suggested that humans were subject to the same dynamics of domestication. Our brain and body sizes peaked during the end of the last ice age, and declined with the spread of agriculture. …
Razib Khan, a doctoral candidate in genomics at the University of California, Davis, writes about genetics, evolution, history, politics and philosophy.
Read the whole thing there.
A couple of general questions I’ve always had about cats and dogs are:
– Why do felines strike us as more feminine than canines?
– Why do we feel house cats have some kind of aesthetic sense, for example, in terms of how they position themselves in a room? In contrast, nobody ever senses that dogs have the equivalent aesthetic eye for where they’re going to flop out and take a nap.
Then the next question would be: are these just random connections to masculinity for dogs and femininity for cats or were sex hormones and receptors selected in particular?