Comment by Intermernet

I have 2 cats that are sisters. They have a very interesting dynamic. There isn't a fixed dominant sibling, they switch back and forth.

They antagonise each-other most of the time, but they also support each other in times of stress. If one goes to the vet and the other doesn't, the initial reaction is hissing and being a dick. Then, after a few minutes, it's licking and comforting.

I don't like to anthropomorphise too much, but they definitely look out for each-other. Equally, they definitely annoy each-other.