When cats end up on the streets as strays and start breeding, if the resulting kittens aren't socialised to humans at an early age, they revert to being the wild animals that their ancestors are. As these wild-born kittens keep breeding the resulting generations are feral, meaning they are wild animals that live in close proximity to humans. Adult feral cats can rarely be tamed but if kittens are caught and socialised early on, they are suitable as domestic pets. The window period for this is thought to be around 5-7 weeks of age. Beyond 8 weeks, some kittens may still tame up but many will not.
My mother was living on a farm and one of the farm workers caught a 3-month-old feral kitten and gave it to her and she kept it, thinking it could be tamed and locked it into a room for a while. After it was let out of the room, the kitten remained living in the house but never allowed anyone to touch her. My mother didn't know what else to do so that's how things stayed for years. The cat even slept on her bed but wouldn't allow handling of any kind and bit a few people who did try. My niece named her Purple Cat
My mother is old and she had to move in with my brother for health reasons. My brother was adamant he wasn't having my mother's cats in his house and vets recommended euthanasia, since the cat was 'asocial' and could not be rehomed. I decided to take her and thought I would try taming her, since she did live in the house although by now, she was about 6 years old. I kept her in my bathroom for about a week and then let her free. She hid in my house for the first month, only appearing for meals and was totally unapproachable. Gradually, she started sleeping on my bed next to Tom, her ginger housemate from my mother's place. I decided to take my chance. If they were sleeping close together, I would start by petting him and then gradually my hand would stray over until I was touching her. At first, she ran away but then she became more accepting until finally, I could touch her and even brush her and she would purr. The whole process took about 6 weeks.
I have had her for four years now she allows me to brush, handle and if necessary, give her pills and flea treatments. She's also very well-behaved at the vet but she hasn't lost her wildness: only I can touch her, she runs away from other people and hides if there are visitors. She loves hunting and eats everything that she catches. She never plays with toys and doesn't meow like a house cat but chirps and trills, as wild cats do. She's very talkative and has loads of tortitude, although she's a tabby tortoiseshell cat. I call her Miss P. She is very difficult to photograph, I'm sure she thinks that the camera will steal her soul: her eyes are beautiful and it's hard to do justice to them.
It's been an interesting experience living with a wild animal who has learned to trust enough to be handled and live in the house and I am not sorry that I took her on, she is a great rodent controller, especially in the previous place I lived in, which was next to the river and the municipal dump and overrun with rats. As small as she is, she even kills large rats, which are dangerous when cornered.