10 Things You Didn't Know About Dung

Animal droppings, or dung, might not be something most of us give much thought to on a daily basis. But there's a lot more to the humble dropping than meets the eye ... or nose. Following are 10 ways in which animal, or human, waste has proved useful, interesting or informative:

1. Because dung is a byproduct of diet, it can reveal information about what plants or animals a particular creature ate. As a biological product as well, dung can provide DNA samples that let scientists determine a creature's gender and other characteristics.

2. The History Channel plans to air a program in June that explores how humans use dung.

3. Using the clues about past plant life contained in dung, scientists can also figure out what the climate was like long ago; that is, how warm or cool it was, how much rain typically fell, and so on. "The plant remains in the dung allow us to determine the mosaic of plants in the local plant community," says Jim Mead, director of Northern Arizona University's Laboratory of Quaternary Paleontology. "The community structure changes with changes in climate."

4. Dung also provides a good way to determine how long ago the creature that produced it lived. Because it is an organic material, it can be subjected to radiocarbon dating, which calculates ages of samples based on how much carbon-14 has decayed since a living plant or animal has died. Another note: samples of fossilized dung are known as coprolites.

5. In some parts of the world, dung from livestock is still used as a fuel for heating or cooking, or as a construction material.

6. Scientists recently discovered that beetle dung helps nature begin to recover after a forest has been ravaged by fire. Beetle droppings tend to accumulate at the bases of trees, where the dung encourages the growth of microbes. Those microbes, in turn, help organic matter to decompose, which returns needed nutrients to the soil. One more note: the scientific term for beetle droppings is "frass."

7. The medical community actually has a scale for classifying the appearance of human feces. Known as the Bristol Stool Chart, the scale helps doctors estimate how long it's taken for food to pass through a person's digestive system.

8. Animal dung can also provide insights into how humans are affecting natural habitats. Researchers from the University of Illinois and Canada's McGill University, for example, recently completed a study of monkey dung that found a link between human-caused deforestation and health threats to the endangered red colobus monkey in Uganda. The more trees that were cut down, the more likely an area would have high populations of parasitic nematodes. Red colobus monkeys infected with those nematodes can develop digestive problems that can sometimes prove fatal.

9. Dung samples can also help scientists discover whether, and when, a creature has gone extinct. A zoologist in Australia, for instance, has been testing 50-year-old droppings to determine whether the now-extinct Tasmanian tiger might have lived in the wild beyond 1936, when the last living specimen died in a zoo.

10. Found on every continent except Antarctica, dung beetles eat just what their name suggests: the droppings of other animals. Ancient Egyptians considered dung beetles to be sacred, believing they could reproduce without females.