when kittens get older do they still treat their siblings like siblings?

If they grow up together, they'll most likely be treating each other the same since they'll be around each other all of the time.

They do not know that the other kittens are siblings, to them they are just other cats.

In the home setting yes, especially if they are fixed.

I disagree with JC. I have seen cats who were siblings in more than one instance, and they usually bond quite tightly. That does not mean this always happens, but considering they spend so much time together, and especially as younger animals, they likely bond just like brothers and sisters do.

I once saw three sibling cats together. One was pregnant and in labor. She was having difficulty with the delivery and to my surprise, her siblings were laying one on each side of her and WOULD NOT leave her side. Perhaps they would have done this, even if they were not siblings, but I think being related/spending time as young kittens added to the bond. AND, the humans in the situation, did nothing to help the cat. They simply left her, and even went out, not calling the vet. She could have died, and her siblings knew this.

Our male and female sibling cats are bonded. Many do this, and you can ask any animal rescue league about this, although any cats who were together either as kittens, or for several years can bond in this manner.

ONLY if they are kept together. If separated more then a month, they will treat each other like "strangers".

Cats do not have the same concept of "family" as humans do. The have no special consideration for a cat because it's a sibling. It's a cat that they may or may not like, and the familial relationship has nothing to do with it. Lots of humans don't like their family either :/ Cats that grow up together often do form a special bond, but that will happen to a pair that is well suited to each other and not because they are siblings.

well not like the playfull puppy type when they are not a puppy but yes they will, i have keeped a puppy from my dog and that still treat each other like mother an daughter so it would be the same for a cat

To a point. If you keep two siblings together, and get them spayed and neutered of course, they will treat them like any other cat. They will be friendly but know realize that they are siblings. most cats, when introduced, hate each other and fight for weeks, months even. This usually doesn't happen with siblings you keep together.

Every cat I have ever owned has ALWAYS recognized its litter mate as its brother or sister, for all of its life. A mother cat will ALWAYS recognize her own grown kitten; and her grown kitten will always recognize her as its mother. Siblings will not attempt to mate with siblings; and a male cat will not attempt to mate with its mother.

This only applies when the cats are raised together, live together for life, and are never separated.