My cat has hard fur on his back along his spine

My cat has hard fur on his back along his spine

Please see photo....what could this be please? its hard to touch.....no liquids were spilled on his back so i dont know whats wrong with him

He eats and sleeps normally

Have you tried rubbing the hard spots with a wet towel to see if that softens up the fur and removes any dirt or dried up goo? You can try to carefully clip the hard fur off with a small pair of safety scissors. It looks like your cat isn't grooming his back for some reason and some fur got matted a bit. Do you comb or brush regularly to keep mats and knots from forming?

Are they matted, with the texture of felt? The picture is too hard to tell. Looks like it could well just be dreadlocks. I had a longhair who would get them along her ruff, but I haven't seen a shorthair have them. But maybe if he's rapidly growing in his winter coat?