Half and half cat

I've been trying to get a decent photo of the state of my cat's fur for a while, and this is the closest I've managed. The poor old thing will be 19 next month, and is really showing his age. Because he now spends a very large proportion of his time asleep, and seems to always sleep on the same side, all of the fur has rubbed off that side. So you can see the line down his back where he has good, fluffy fur one side, and is bald the other!