My girlfriend works at a vet clinic, and a cat that has been there for a few months (Pekoe) needed a home, so i said i would foster her for the week and see how she got along with my other cat (Zeus). Both are fixed females, and they are both roughly a year old. Now, backstory on Zeus: she is insanely energetic, very badly behaved, and doesn't like being held. she's not mean, she just does lots of things she knows she isn't supposed to. Pekoe is a gentle, calm, loving kitty who got along with all the other animals at the clinic. my fear was that Zeus would tear Pekoe to pieces, but the exact opposite happened. Suddenly, Zeus is very calm, cuddly, and very curious about Pekoe, and wants to sniff her and get to know her. Pekoe, on the other hand, will outright attack Zeus if she gets within a few feet. They can't even be in the same room or Pekoe will growl herself silly, and if they make eye contact Pekoe hisses at Zeus. I am utterly confused by this behavior, given their behaviors before they met each other. i definitely don't think it's a territory thing, because my apartment is obviously Zeus's turf, but she is welcoming, whereas Pekoe is freaking out. i don't know what to do! they've been in separate rooms for two days, with the occasional attempt made by me to acquaint them, and Pekoe still wants to tear Zeus's head off as soon as she comes near, even though she's not being invasive at all. any recommendations? or perhaps explanations why Pekoe is freaking out and Zeus isn't?