Reading Noob_Sareena's post about his new kittens led me to think of the relationship between my own cats, and some questions about it.

I have two cats: Cali, a 6 year old female my family adopted at the age of 9 months, who had been abused by her previous owner and abandoned at a gas station (also of note, although she was spayed when we adopted her, she had had a litter of kittens, which was drowned); and Leo, a 1 1/2 year old male who we got for Christmas ('02) at the age of about 6 weeks from my sister's boyfriend.

When we got Leo, Cali did not react well to him. She hissed and scratched at him, and ran off to hide. She spent the majority of her time during the next couple months hiding away in my parents' room (the top floor of the house), but Leo, despite our admonishment and, at one point, a cardboard barrier placed on the stairs, repeatedly ran upstairs to try to get acquainted with his standoffish new housemate. Gradually, Cali became less fearful, and roamed the house more, but Leo often picked playful fights with her, sometimes ambushing her and pouncing on her.

As Leo grew to his full size (he's now longer and taller, although much thinner and lighter, than Cali) he gradually stopped his playful aggressiveness with Cali, and in fact seems to have lost interest in her almost entirely. Cali also behaves differently around Leo. For example, the two eat from conjoined ceramic bowls, usually at the same time. If Cali gets there first, but Leo comes before there's any food in his bowl, he'll begin to eat from Cali's bowl, at which point Cali will back away, until my mom (who usually feeds them) puts food in Leo's bowl. Also, when Leo is near her, Cali often sniffs Leo curiously, and Leo will usually either walk away, or perhaps lick the top of Cali's head.

One other thing I find very unusual comes in the wake of the fact that, last November, my family moved to a new, larger house in the same town, about a mile from our old house. The unusual thing is, Cali seemed to get used to the new house in a matter of mere days. Leo, however, when first introduced to the house, spent hours crying in fear and confusion, and hid away from everyone. It took him a couple weeks to start getting settled in, and really get acquainted with his new domicile. It's strange, because Leo (who spends a lot of time outside at night) has always been very playful and curious, and more outgoing than Cali.

Can anyone give me any insight into my cats' behavior patterns? Has Leo, through his playful fighting, asserted dominance over Cali? Does that type of thing occur between a male and female cat? Regarding the move, what could have caused the apparent reversal in demeanor between the two? Cali has always been fearful of strangers, and still is, but Leo wasn't, at least until that point. Now he runs and hides from everyone except my family and some of my sister's friends (such as her boyfriend who gave him to us). Has he learned this fear from Cali, or is it natural for cats to become more fearful of strangers? The latter doesn't seem to be the case, as several friends and relatives of mine have cats that, even when I first met them, acted as though they had known me their whole lives. Anyway, any thoughts on these situations?

Also, feel free to discuss any issues and ask any questions regarding animal behavior for discussion by the MKO community.