We have a couple of young cats that were part of a litter that were "rescued" as little kittens from a feral mom, and fostered. They are amazingly well socialized - so much so that they're more like dogs than cats. But they show the effects of having been taken away from the mother early on, like they didn't get to nurse enough to really be satisfied.

One sign of this deprivation is that they tend to chew on stuff they shouldn't, like mail or the newspaper if you leave it on the kitchen table. Another sign of it is, if I lie on the bed - on my back, with my arms crossed above my head and my head on my hands, as I often do if I lie down during the day to catch my second wind - and I'm wearing no shirt, or a short-sleeved tee, the male sticks his head in my loathsome, smelly, hairy armpit, looking for a nipple. And sometimes he bites.

Peter.