The Thoughtful Animal science blog has published the latest about the origin of domestic cats. It seems that they are nested within the Central Asian and Near Eastern desert cats. Mitochondrial DNA pinpoints five ancestors. Go and look at the phylogeny and read the explanation: it’s wonderful.
The comments talked about domestication and I added my scenarios.
It’s pretty clear that when people started to keep grain against future need, the grain attracted rodents and the rodents attracted cats. Eventually, the humans and cats got used to each other. I believe that cats are commensals, ‘eating at the same table,’ rather than domesticated in the same sense as other animals.
Once everyone had enough cats, excess kittens were likely to be drowned at birth to keep them from overrunning the household with starving, inbred cats. A kitten of unusual color was more likely to be kept, so novelty was a survival advantage as long as fewer than 10% of cats were that color. (I read that in Scientific American, ages ago.)
Unlike most domestic animals, cats have roamed and bred freely until about 200 years ago, when people who noticed the variation in cats had the leisure to keep them caged and control their mating to maintain and eventually produce breeds.
Cats were recognized as important rodent killers. A cat was allowed to roam freely according to English Common Law: otherwise it could not fulfil its function. There was a fine for killing a cat (before the witch hunts and their anti-cat prejudice). British ships had a position of Ship’s Cat on the roster, with a small allowance for its food. Just about every barn still has its family of half-wild cats. So I’d say that the pest-control function is basic.
Rat-killing takes courage. Some cats regard it as a paying hobby and kill the occasional rat or mouse to eat. Some stick to mice. Others have been famous for killing several rats each night and leaving them where they could be admired. Kittens of a good ratter were prized because she would teach them how to hunt.
Cats that are socialized and handled as kittens and fed as adults remain kittenlike to their humans throughout their lifetime. However, meet them outside and you encounter a much more adult personality, warier and focused on cat business. The secret of their success is that they can return to their childlike, trusting state for us and then go back to being semi-wild, specialized predators.
Domestication could have happened differently: kittens are incredibly amusing and baby-cute–probably the best entertainment before television. If there was a nearby lair of cats attracted by the rodents around a human settlement at the beginnings of agriculture, Momcat might have remained wary, but there would be a more-or-less constant supply of half-grown cats being playful. When the cats were more accustomed to humans, there would be kittens bopping around, tripping over things, attacking plants, climbing, and fearlessly chewing on proffered fingers. Kitten chases a butterfly–human throws a leaf. Kitten races in circles to catch it–human drags a stem of grass past the kitten. Kitten grabs at it frantically with starfish paws. Human throws a scrap of meat. Kitten devours it after somersaulting over it. Human throws another scrap. Gradually, humans take on the role of lifelong tidbit provider and substitute parent. Cat sleeps where it’s warm, gets up and kills rodent pests, puts up with human babies pulling its tail, and all is well.