Researchers have found tracks of dinosaurs 20 and 30 meters long. The big ones were of herbivorous dinosaurs of different species and the small ones - of their pursuers
2.6.2002
Avi Blizovsky
Researchers have analyzed 163 million year old dinosaur footprints. In a study published this weekend in the journal Science, British researchers claim that 40 traces of fingerprints preserved in stone at a site in England were caused by vegetarian dinosaurs that gathered in one place to escape from madmen that gathered nearby.
Some of these dinosaurs, measuring 30 meters in length and weighing 10 tons or more, crossed the open tidal flat together, perhaps trying for their lives. They were all sauropods of different species. At a not great distance from these tracks, tracks of Megalosaurus were seen.
This is a smaller but faster animal. It was a meat eater with sharp teeth that reached 20 meters in length. The tracks led in the same direction and were about the same age as those of the sauropods. Megalosaurus was a theropod, a member of the same family as Tyrannosaurus rex, the heaviest meat eater that evolved millions of years later.
The carnivores followed the herbivores, says Julia Day, a paleontologist at the University of Cambridge in England and lead author of the paper. According to him, the tracks prove that the sauropods were many kilometers away from where the plants they ate grew, which was rare because the large herbivores must eat continuously. Therefore, either they were in the course of migration from one food area to another, or they escaped from predators.
The sauropods moved slowly, and all in the same direction, with each animal leaving a series of tracks. In one case, footprints of a smaller creature appeared next to a larger sauropod. Apparently a parent and one of its offspring moved in the ancient muddy plain.
According to her, the grouping of herbivores of different species is a common thing. In today's Africa, zebras and other wild animals often move together on the grasslands and along the rivers of Tanzania and Kenya. This is the first evidence of such a joint gathering of dinosaurs. She says "If they were migrating, they were looking for a new food source and a place to nest. This is an area that is covered by the sea at high tide, and therefore the footprints had to dry quickly in the sun. Today the soil there has turned into limestone. According to her, the type of animals, their size and weight can be identified by the shape, depth and width of the footprints.
