Fossil tooth proves for the first time that dinosaurs migrated - just like birds
Palaeontologists have long wondered whether dinosaurs migrated, like today's birds or animals such as wildebeest.
Now it seems that the idea of giant herbivores thundering across the plain was not so far-fetched - and the placid beasts may even have been pursued by allosaurs, a distant cousin of T-rex.
University of Colorado researchers have proved for the first time that dinosaurs would migrate when conditions became hard.
The Camarasaurus dinosaurs would spend summer in a flood plain lapping up water, then during the dry season would head for hills where they could find food and ready supplies of water.
The researchers used oxygen in fossilised teeth to prove that not only did the dinosaurs migrate, it wasn't a one-off, but instead a regular, seasonal migration, similar to the movements of today's wild birds and animals.
Radioactive isotopes in fossilised teeth 'proved' that dinosaurs were drinking from different water sources in a regular cycle.
The researchers concluded that, just like today's animals, the dinosaurs would move to greener pastures when conditions became hard.
When the dinosaurs 'migrated', predators probably followed, said the researchers, led by Henry Fricke of Colorado College.
He told The Times: 'I think it would have been rather slow going, with animals eating as they walked, maybe only going a few kilometres a day at most.
'I also imagine that herd size couldn't have been very large, in the 10s to low 100s, else there wouldn't have been enough vegetation to support them.
'Lastly, I imagine a lot of noise - rustling of trees as leaves are eaten, and lots of farting: sauropods didn't chew, they did all of their digesting in their gut.'
They are now looking for evidence that predators such as allosaurs followed the herbivores on their journeys.
Paul Barret of the Natural History Museum in London told New Scientist, 'A mass migration is basically a huge, walking supermarket.'
The researchers used oxygen in fossilised teeth to prove for the first time that dinosaurs DID migrate between the flood plains where they 'wintered' and the hills where they could find food and water in the dry seasons.
The radioactive signature - the ratio of different isotopes - of oxygen in fossil teeth was different to the ratio in carbonate rocks from the floodplain.
The researchers concluded, in a report published in Nature, that the Camarasaurs sometimes left the area.
By drilling through the teeth, the researchers found that levels gradually changed over five months - strengthening the idea the migration was seasonal.
Source: Daily Mail