new cat part 2

something really strange has happened my female adult cat who was fine with new kitty to start with got right up close to him and he hissed at her now she constantly growls and makes weird noises at him although she isnt puffing her fur or her tail up she just sits there and does it why is she doing this when to start with she was quite happy with him. shes even started growling at the 9 month old kittens which are her babies

She might be showing,the New Arrival,who,the Boss is,as Mama cats ,will hiss at the Young Ones,to keep them,in line!