Tooth analysis shows dinosaurs headed for the cool hills in summer

Nov 14, 2011, 10:56 GMT

London - Certain dinosaurs migrated hundreds of kilometres during the dry summer months every year, moving to cool and moist mountain regions, according to a new study by palaeontologists in the United States.

The scientists investigated the enamel of the dinosaurs' teeth and published their results in the British scientific journal Nature.

Henry Fricke of Colorado College in Colorado Springs investigated the composition of the tooth enamel of fossils of Camarosaurus lentus, a large herbivore of the Late Jurassic. The dinosaurs' habitat in Wyoming and California was primarily flat and low-lying riverine areas.

But the proportion of differing isotopes of oxygen in the enamel showed that the dinosaurs had at times not drunk any water in these regions.

While the teeth were growing, the animals moved to higher altitude mountain regions to slake their thirst, probably some 300 kilometres to the west, according to the research team.

The varying concentrations of the oxygen-18 isotope reflected the area and more particularly the altitude of the landscape where the dinosaurs' drinking water came from.

Analysis of the various growth layers in the teeth showed that the dinosaurs must have migrated back and forth between the mountainous region and the lower lying areas. 'Presumably the animals left the lowlands at the beginning of the dry summer period and returned once more in the autumn,' said Fricke.

This could be an indication of a regular migration cycle much like that undertaken by modern animals across the plains of East Africa.

But it could also be an exception resulting from an unusually dry summer. Further investigation of the dinosaur remains are planned to clear up whether the huge beasts went walkabout every year.