This would depend on which type of cat's scratcher you are providing to your bunnies. If you are going to provide a corrugated cardboard scratching post of a cat to your bunny, he will try it out. Male rabbits aren’t usually as big on big digging as their female counterparts so they will not dig it as much as they will scratch it. You can also sprinkle some dried herbs or oregano over the post to encourage them to chew or nibble it. Rabbits seem to like the texture of cardboard posts and if your bunny is chewing or scratching on a cat scratcher, you can be relieved that it will not scratch or chew your furniture or electric chords around your house. But if you are trying to use a wood scratching post or a post that is covered with rope, they won’t be much use to bunnies. Since the rope that is used for cat scratching posts isn’t made for bunnies, there is no guarantee that they may be safe for your rabbit.