Question on Dinosaur Migration

[Thorondor 33]

Is it possible that Dinosaurs such as Carnotaurus would have moved up from South American to North America?

I think they would, because really, even though no fossils have been found in North American of Carnotaurus, that fosen't mean he wasn't there.

[thetyrantlizard]

Probably not, unfortunately. Carnotaurus was an abelisaurid, which is a family that can be found only in the lands once united with Gondwanaland (Antarctica, South America, Australia, Africa, Madagascar, India, etc.) The Eurasian & North American continents were already forming the separate supercontinent Laurasia, where the tyrannosaurids were the apex predators. It is possible that a relative of Carnotaurus may one day be found in Laurasia, but it's not likely.

[Thorondor 33]

What about other species?

[thetyrantlizard]

Depends. Somehow the titanosaur sauropods were able to return in the Late Cretaceous to North America (Alamosaurus), and there are unexplained occurrences of iguanodons, etc. where there are not supposed to be any. But the generalizations still hold, usually.

[Thorondor 33]

I treat Dinosaurs like animals of today. I don't think Dinosaurs acted much differently. So I thought that maybe if Dinosaur's surroundings began to change, the Dinos would move off. For example, if too many carnivores came to an area, the herbivores might mobe off.

[thetyrantlizard]

It is possible, even certain, that some dinosaurs such as sauropods were constantly on the move--they would have destroyed too much vegetation to remain in one place. However, by the Cretaceous Pangaea had begun splitting in two, then into fragments, so certain families of dinosaurs were stuck in one continent and couldn't migrate into another. For instance, only in the Tertiary/Cenozoic were North and South America connected through Panama.