Pregnant Stray & My Female Kitten

Question
A pregnant stray has decided to adopt me. I have 2 cats- one neutered male and one un-spayed female. I brought the stray inside. She laid at the front door for a few minutes and then I set her up a nice little nesting area in a different room. My female happened to walk by where the pregnant stray was laying and absolutely FLIPPED OUT! She was running around, hissing, screaming and literally jumping off the walls! Now she won't let me get near her and keeps growling and hissing- what's going on?

Answer
Hi
the behaviour you describe is absolutely normal. Another female cat has invaded your un spayed cats territory and she is acting in a frightened way (often aggression is a sign of fear rather than of actual anger).

Unfortunately there is no real solution to this, other than separating them all the time, or getting your female cat spayed which will calm her down and make her less territorial.

There is a procedure for introducing cats to each other for the first time but with two females, one pregnant and the other unspayed this could be pointless.  the procedure can be found on my website here
/introducing-cats.html

Hope I have been able to clarify the situation for you.

best wishes Kate