I recently learned of - but have never tried - a cheese from the Himalayan region of South Asia that is reputed to be the "hardest cheese in the world". Apparently it is exported to the West as a dog treat.
I don't know why nepali version is dried so much, but it becomes impossible to rehydrate and hence, unusable.
Despite the initial stick shock on the price, we've found them very effective dog chews, threading the needle on lasting a long time but also retaining interest over time relatively well. Also threading the needle on being designed to come apart safely, yet not instantly disintegrating. In late-stage capitalism part of what you're paying for in that price is that you won't need to buy them very often, if you get the correct hardness level for your dog.