Even Small Multicat Environments Need Multiple Options
Even if you live in a small apartment you can provide multiple scratching options. Scratch pads can be attached to walls. If you have a cat tree in the environment, wrap the support posts with sisal so it can serve double-duty as both a tree and a scratching post. If you have a cat who prefers scratching on bare wood, leave one of the support posts unwrapped.
Corrugated cardboard scratching pads are also great for small environments because they don’t take up much room.
Marking Behavior in Cats
Since scratching is a form of both visual and olfactory marking, it can add to overall tension if one cat goes over to scratch and is faced with the evidence that an opponent cat has recently just scratched there. You may find that by supplying more than one post, the cats may be able to claim their own little scratching post turf. Since scratching is also a displacement behavior, the ability to scratch instead of engaging in a conflict might help maintain harmony.