We've all seen it, on warm summer days if the cat is allowed outside he runs over to the first patch of mud he can find and has a good old rub around in it. This is not a behaviour exclusive to cats, many other mammals also enjoy rolling in the dirt, but why?
This behaviour is known as "dust bathing". Having never rolled in the dirt myself, I can't actually say what it feels like, but I can assume to a cat it actually feels quite nice, a bit like a massage. Releasing tension in the skin, rubbing itchy spots, and stretching the body in various positions. It could also help to remove loose hairs from your cat's coat.
We can also speculate that the dirt has a cooling effect on your cat, so it feels nice in to do on a hot day.
Some say that it helps to remove parasites such as fleas, I'm not entirely sure if that is true. It could be.
Scent marking may play a roll in dust bathing, as the cat rolls, he marks the area with scent glands which are located on their paw pads, cheeks and the top of their head.
Others speculate that it's to get rid of the smell of the indoors. It would be interesting to know if stray and feral cats also roll in the dirt, I suspect they do, which would blow that theory.
I genuinely believe that the main reason they roll in the dirt is because it feels good, and they can. A bonus is that it annoys us when they traipse dirt back into the house and leave a gritty little patch on the sofa or in the bed! This may be slightly annoying, but cats seem to derive so much pleasure from rolling in the dirt that it's a small price for us to play. Besides, we should be grateful, dogs like to roll in much worse things than dirt. I have never attempted to stop this behaviour in my cats.
Photo courtesy of Derek Bridges.