New kitty

I just adopted the cutest little Siamese kitten today. The problem is that my 4 year cat is hissing and growling and not being nice. It's only been 2 hours since I got him home but does anyone have any advice? Will this behavior from my other cat disappear?

I advise slowly introducing them to each other. A common mistake when getting a new pet is to assume that everyone will get along. But that's not always the case (especially in cats so I hear). Cats are territorial and your current cat probably sees these kittens as invaders. A threat to its territory.

For me I'd robably work on them over the course of the day. Introducing scents to them. Like...wiping your kittens with a grooming mit then grooming your existing cat. Slowly the scent will be introduced to your existing cats territory then you can introduce the cats.

Keep the kitten in a separate room for now, and introduce them over a few days or even weeks. There is a way to do it, but could you also provide the kitten's age and the sex of the older cat?

My older cat is a female and my new kitten is a male. The female was the runt of the litter and her mother abandoned her and I found her in a sewer. I think her growth was stunted because she doesn't know how to use her claws and she can't jump on things that normal cats should be able to jump on (like a chair). Now, since I got this kitten, my older cat won't come near me and hisses at me.

That's because you smell like the new one (from having handled her), but that will pass.

I just went through this-- keep them separate for about a week so they get used to each others scent. Then after about a week switch rooms- put the kitten where the adult cat was and vice versa- still keeping them separate. I got a Feliway plug and put a little perfume on each so they would smell similar when I finally introduced them.

I didn't make a big deal about introducing them, I simply opened the door separating them and went on the computer and ignored them- I kept a very relaxed, quiet, no stress atmosphere and they were fine.