Paper is a thin sheet of cellulose fibers mashed together so hard that they stick to each other. To make paper, you need cellulose fibers and the means of mashing them. Mashing means technology has developed as rapidly as you would expect since the industrial revolution, but the sources of the fiber that goes into paper have remained essentially unchanged: in the old days paper was made out of wood or linen rags, and these days it is made out of linen rags or wood. It is possible to make paper directly out of flax, but making linen is a more profitable use of the raw material, and the rags are therefore cheaper. It is also possible to make excellent paper out of hemp, and one of my favorite conspiracy theories claims that the real reason that marijuana was made illegal was pressure from the linen lobby, who wanted to get rid of a powerful competitor product.
Trees, flax and hemp are all plants, so the first step in making paper has always been the harvesting and processing of some kind of plant. And it could be argued that that is still the case. But for the people involved in the process it no longer always feels that way. Because sometimes the collection of the plant material and the first step of processing are now carried out by animals.
Cellulose forms a large part of many plants, and of the diet of many herbivores. It is difficult to digest, which is why cows have all those stomachs, and why ruminants and some other animals eat their food twice. In fact, it is so difficult to digest that a lot of it goes in one end of the animal and comes out of the other end undigested. All you have to do is clean it up a bit, and you can make paper out of it. Given what a blindingly obvious idea this is, it is remarkable that paper has not been made this way for ever. Another demonstration, if it were needed, of the power of prejudice over reason.
Perhaps it also has something to do with the fact that the process of 'cleaning it up a bit' is not that simple. According to their website, Creative Paper Wales, famed in Snowdonia for their flagship product 'Sheep Poo Paper' boil the fresh sheep droppings in a specially designed pressure cooker at over 120°C to sterilize them, and then wash them repeatedly over a period of days, before doing dreadful and secret things to the resulting pulp to get it into a suitable state for paper production. Still, the raw material is a waste product, suitable only for use as fertilizer, the final product is high-quality organic paper, and a by-product of the washing process is a liquid fertilizer, so nothing is wasted.
Not only sheep can be exploited as cheap pulp harvesters: plans are afoot in Snowdonia to produce reindeer poo paper for Christmas, elephant dung paper is improving the public image of pachyderms in Sri Lanka, and Creative Paper Tasmania have been proudly producing roo poo paper since 2003. But the pluripotent papyrofacient potential of poo only became known to a wider international public when the story broke that the Tasmanians had started making wombat poo paper. The quantities are small, but there is just something about wombats.