Why does my cat growl while being affectionate?

[4catsnomoney]

I have a 6 year old black cat who has always been skiddish and not fond of contact with humans or other pets ever since we got her at the humane society. We recently found a stray kitten and I have noticed that Lyla (6 year old cat) actually seems to like the kitten and lets her come near her and will even cuddle and groom her sometimes... But she makes a growling noise as she grooms her? Like she is totally holding the baby down so she can't leave but she is making a horrible growl as she bathes her? We are confused about this and not sure what it means so I was wondering if anyone has ever seen this type of behavior where a cat makes distress noises while being affectionate with other cats?

 

[margd]

I'm so sorry you haven't gotten a reply before now. We are all usually much faster at answering questions.  And your first post, too!  What a welcome.  Well, a happy belated welcome to TCS!  

I don't actually know the answer to your question but can offer a couple of theories.  First your older girl might be demonstrating her latent maternal instincts and is drawn to wash the kitten as she would if it were her own.  The growling is just a warning to hold still.  The other possibility is that she's expressing her dominance over the newcomer to the family.  

Again, a belated welcome!