Hello this is my 1st time posting on this site I hope to get an answer. I currently have a 10 yr old male cat that I adopted from the humane society about 5 yrs ago. I recently adopted a 3 yr old female cat from the same humane society. When I adopted her they said she was found w/ a group of cats and they thought she may be feral but then they said she wasn't feral or else they wouldn't have put her out for adoption. They also said she probably has already had a litter of kittens. My thinking was that since she was found w/ other cats she would be good w/ them. When I met her she instantly climbed in my lap and fell asleep which is what my current cat did when I adopted him so I thought it was a good sign. So I brought her home, had her in her own room separated from my current cat for 2 weeks because she got sick after a few days. Well now we are slowly introducing them we will let the new one out for a while to roam the house. When the two cats first met they would do a low growl and sit near each other just growling but that's it. Anyways so now the new one when I let her out of her room just randomly locks eyes on my current cat and gets this wide eyed look then she goes into the hunting crawl stance and make the hunting clicking sound and tackles my current cat. Claws out no biting or blood yet but I am nervous it will escalate if it continues. I'm wondering why she is going into the hunting position? Is she trying to hunt and kill my current cat? Is this a normal behavior when introducing cats? My current cat is completely fine and wants to try and be friends but the new one continues to stalk him. What can I do to make this stop? I know some people say to just let them fight it out but I do not want my current cat to get hurt. Also she is extremely loving w humans but sometimes when I'm standing next to her she randomly bites my foot. Not super hard but it still hurts. What do I do?