So, I've had a kitten before but have never had two cats at once so have never had to introduce two cats. However, me and my mom decided it was time to get a kitten and then decided we should get two. They're from different litters as we fell in love with the both of them. One is about 9 weeks, one is about 8 weeks. We got the 9 week old yesterday and it's a male, the 8 week one todag and its harder to tell the gender but we think male. Anyways, to get to the point - introducing them. I had planned to leave the one we got today in the crate for a bit in the same room with the other kitten but my mom decided to come in and let it out. I've left them out since as it hasn't been too bad. They've been hissing when they get too close to each other and now the for sure male is hyper and there's been some swatting. I know it's not encouraged to just introduce them abruptly but I figured that since they're not attacking each other its fine? But my question - will this pass after a couple days? Will they learn to tolerate each other?