Thank you to the lovely Jen of Spacedog fame for giving me the heads up on this article. Taken from the book ‘The Origin of Faeces What Excrement tells us about evolution, ecology and a sustainable society’ by David Waltner-Toews, this picture and article is both funny and interesting!
When I began writing The Origin of Feces, after a quarter century of teaching and research on the epidemiology of zoonoses (diseases that can travel from animals to humans) and foodborne and waterborne diseases, I knew a great deal about the environmental and public health problems associated with excrement. The solutions to these problems seemed straightforward and technical. What struck me as I was doing research for the book was the profound way in which excrement is embedded in ecological (and, by extension, cultural) relationships. Here are five things I learned, which you should know, about poo.
1. No shit, no life
Before life, there was no excrement. The second that membranes enclosed biochemical reactions – that is, as soon as life was born – materials passed selectively into and out of those cells. What passed out was “waste”. Yet in that waste, nutrients and energy were recycled, and webs of life were made possible. Without faeces (in its broadest sense) life (and humanity) would not be possible.
2. Poop has a purpose
Multi-cellular animals are faced with complex issues related to their need to defecate and their own ability to reproduce. Some deer may eat the dung of their young, birds carry faecal sacs of their young from the nest and drop them into streams, and caterpillars shoot their frass far away from themselves. Still other animals, such as bushbuck and genets, use dung middens as places for inter-sexual communication. Predators often mark territory with faeces. Other species have taken advantage of some of these behaviours. Sloths create dung middens that serve to redirect predators away from their homes in the trees, and also to indicate mating sites not just for themselves; these dung piles also provide means for the moths that live in their coats to reproduce. When the sloth descends to defecate, moths living (and feeding on debris) in their coats oviposit in the dung. The larvae hatch, pupate and feed in and on the excrement. Several weeks later, moths emerge, looking for another sloth to call home.
3. Dung is delicious
Within a multi-species landscape, human and other animal behaviours that have evolved to optimise reproductive success also serve to disperse seeds and replenish landscapes. Dung beetles, for instance, which live on every continent except Antarctica, use faeces as a source of nourishment for their young; at the same time, by burying faeces in the ground, they are integrating nitrogen, phosphorus and other elements into the soils which support the plant species that feed the animals that provide food for the dung beetles. Taking an ecological view, the dung beetle is not just an organism. It is also a bundle of nutrients, information and energy: each organism, through its eating of the excrement, is an embodiment of excrement. We are, all of us, what we eat. Parasite cycles give us a rich picture of how the nutrient essence of excrement, if not its form, can move through the ecosystem from intestines of birds and mammals to the soil, to plants and insects, and back again to mammals. The parasites and their hosts and predators are, in fact, the re-embodiment of the deconstructed excrement and the life cycles of parasites of concern to public health are life cycles of excrement. The global distribution of faecal-related bacteria and parasites in food, water and wildlife (e.g. E. coli, Salmonella spp, Giardia spp, Toxoplasma spp) tells us not just about the ubiquity of hazards, but also about the webs and pathways through which the nutrients and energy in excrement are distributed globally. One implication of this is that killing off any species, however small or obnoxious, closes off certain pathways of nutrient recycling and hence will affect all of us sooner or later.
4. We are caca-conflicted
Conflicted human attitudes toward faeces have deep biological roots and reflect relationships to excrement seen throughout the animal kingdom. In evolutionary terms, positive associations with the scent of excrement may be rooted in biological urges to define territory and communicate with others, as well as the observation that food plants grow better in areas that had been manured. When human populations were mostly nomadic and when settlements were small and sparse, the positive associations with excrement outweighed whatever risks were perceived. This positive view of manure, historically reflected in a thriving commercial trade in excrement, has persisted when connections between city and countryside have been explicit and open, and in rural agricultural areas today. As we have increased our understanding of transmission of killer diseases such as cholera and childhood diarrhoea in the last few centuries, however, and as the beneficial association of flush toilets and clean bathrooms with survival has become clear, city dwellers have learned to take an unambiguously negative attitude towards shit. The shift from a positive view to a negative view is thus rooted in shifts from people living in the country to people living in cities, to a loss of connection between food producers and consumers, and to our increased scientific understanding of causes of disease.
5. Crap relationships matter
Excrement is part of what has been referred to as a “wicked” problem. The “problem” of faeces is deeply embedded in a restructured global (eco) system of livestock-rearing and trade, as well as water-based disposal systems (flush toilets and sewage treatment plants); these were developed to improve food supplies, promote health and stimulate economic prosperity. Nevertheless, the solutions to problems, while effective if viewed narrowly, also result in a depletion of potable water, and a major redistribution of water and nutrients from some ecosystems, which are thus impoverished (e.g. soy beans in Brazil), through animal and human faeces into other ecosystems, which are thus over-fertilised (particularly those where industrialised animal rearing has been selected as the solution to the “food problem”). Solutions to excrement-related public health and environmental problems call for a new understanding of the science of relationships among things (as differentiated from a science of things-in-themselves), and will only be sustainable if they account, simultaneously, for the manifold ecological and cultural webs in which they are embedded.