Faeces, plop, poo, number two, excrement, defecation, droppings, dung, excreta, stools, and crap. All splendidly evocative words describing a substance that we deal with on a daily basis but pretend we don't. But why be so coy, when faeces are like little signatures that we make on the world? Even now animals excrete in the woods, leaving little history clues for palaeontologists¹ of the future.

The study of fossil poo has brought the feeding habits and motions of the past into clear prehistoric focus. The plop of dinosaurs, giant ground sloths, and Neanderthals have all passed into history. Coprolites, or rock-hard fossil dung, isn't simply the result of a dry curry or too few prunes, it's the result of preservation and mineral replacement. Fossilisation is a rare event - consider it unlikely that even a single motion in your entire life will be preserved as posterior posterity.

Locked in these mineral nuggets are clues to the feeding strategies and diets of animals long gone. Dino droppings have revealed herbivorous heaves, packed with chewed fossil leaf material and tell-tale pollen. Through these incredible insights we can digest and follow through investigations to reveal a very detailed picture of what plants were on the menu. Fossil dung from predators tell a different tale; they are packed with bone fragments - the colonic rumblings of a Tyrannosaurus Rex were apparently like a pulverising mill.

These feats of reptilian rumination are all older than 65 million years. More recent semi-fossilised poo, such as those younger than 100,000 years old, can still harbour traces of DNA and can give an even better idea of a creature's diet. A Bristol scientist examined a 19,000 year-old 'giant ground sloth' turd to reveal seven kinds of plant DNA, including capers, lilies, mints and grapes. Which just goes to show you that faeces isn't just a load of crap.