Signs Of Life

Footprints have been vital to our new understanding of dinosaurs. Whereas bones allow scientists to reconstruct the dinosaurs' physical appearance, footprints offer clues to their behaviour - how fast they ran, whether they lived alone or in groups, how they cared for their young, and how they fared in the desperate survival game as hunters or hunted.

From fossilised footprints, an expert may be able to tell whether a creature was walking or running and at what speed.

Sometimes, patterns of footprints offer 'snapshots' of dramatic encounters. In Texas, one set of tracks seems to show a single giant plant-eating sauropod being pursued by a pack of carnivorous dinosaurs - the sauropod's broad heavy prints are surrounded by the imprint of lighter three-toed hunters. In Queensland, Australia, large numbers of hypsilophontids, small jumble of footprints as they fled in panic from flesh-eating theropods.

Elsewhere, it is the density of the dinosaur tracks that astonishes, revealing the extraordinary numbers of the creatures that once roamed the planet. There are so many dinosaur footprints on the eastern slopes of the Rocky Mountains, in Colorado and New Mexico, that the area has been dubbed a 'dinosaur motorway'. Geologists believes the millions of tracks record an annual mass migration of dinosaurs, similar to the great movements of wildebeest across the Serengeti Plain in modern-day Africa.

Reconstructing the life of the dinosaurs will always be a work of the imagination. But their footprints are the closest we can come to the liing reality of the dinosaurs' world.