* Sensory Stimulation: Cats are highly sensitive to textures. Rolling on rocks might provide a different kind of tactile experience than rolling in grass. The rough texture could be stimulating for their paws and fur.
* Scent Marking: Cats have scent glands on their paws and cheeks. Rolling on rocks allows them to deposit their scent, marking their territory and communicating with other cats.
* Grooming: Cats often groom themselves by licking and scratching. Rolling on rocks could help distribute natural oils and remove loose fur, similar to how they use scratching posts.
* Playful Behavior: Cats are playful creatures. Rolling on rocks could be a way for them to explore their environment and release energy.
* Temperature Regulation: Rocks can absorb and retain heat, making them a warm spot to lay on in cooler weather.
It's also important to consider that cats have unique personalities and preferences. Perhaps your cats simply enjoy the feeling of the rocks, find them more appealing than grass, or have learned to associate them with positive experiences.
If you're concerned about your cats' behavior, it's always best to consult with your veterinarian. They can rule out any underlying medical conditions and provide you with personalized advice.