When dinosaurs trampled the highways

FOSSIL HUNTERS have discovered vast swaths of rock peppered with dinosaur footprints which are providing them with rare insights into the creatures' behaviour.

Tracks over 100 million years old have been uncovered in at least 600 locations around the world, providing details of how the animals moved, hunted and organised themselves into social groups.

Ichnology - the study of ancient tracks - has generated a renaissance in dinosaur research, according to Martin Lockley, a palaeontologist from the University of Colorado at Denver. Writing in Nature, Dr Lockley says that an explosion in the discovery of fossil footprints is proving to be one of the most valuable sources of information about dinosaurs.

"As recently as 1962, only about 27 dinosaur footprint localities were known worldwide. Now the number is over 300 for the western USA alone."

There are at least three "dinosaur highways" in America where the densities of tracks average about a million per square kilometres over areas ranging from 1,000 to 10,000 square kilometres.

Dinosaur footprints have been known about for centuries although they were not recognised as such. A trackway in Germany is believed to have inspired the dragon slain by Siegfried in the medieval legend of the Nibelungs; a dinosaur footprint in Sussex gave Sir Arthur Conan Doyle the idea for The Lost World.

Dr Lockley says that dinosaur highways also show that young dinosaurs were far more common than the fossil skeleton records suggest. In one area of western America, the number of dinosaur tracks found in rocks dating back toJurassic times is equivalent to the total number of dinosaurs in the world identified from fossilised skeletons, he says.

Measuring the distance between fossil footprints has enabled scientists to study the gait of dinosaurs and estimate their running speeds.