No its just a pack thing, they have no idea its their biological mother. No their smelling to make sure there in there pride. There have been lots of cases where a mother cat will take in and raise stray kittens(the kitten will also think its mommy and start nursing). I even heard of dogs taking in a kitten in the pack and thinking its her puppy.
mmmm i didn't know that really -_-; ... but cats depend on the smell like when a cat come from another place and when he want this place he just put a smell in the area and this just for the male cats and he put this smell like he want to define his area ... and for the sorry you told me now i have heard of it but before 3 years i think and i didn't remember it until you remind me of it ... but if the cat nurtured whit his/her mother that mean he can define who is his/her mother .... =^_^=