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Paleontology

During the Cretaceous time period, the Arctic still had seasonal snows, though only a light dusting and not enough to permanently hinder plant growth. Animals such as the Chasmosaurus, Hypacrosaurus, Troodon, and Edmontosaurus may have all migrated north to take advantage of the summer growing season, and migrated south to warmer climes when winter came. A similar situation may also have been found amongst dinosaurs that lived in Antarctic regions, such as the Muttaburrasaurus of Australia.

However, others claim that dinosaurs lived year-round at very high latitudes, such as near the Colville River, which is now at about 70° N but at the time (70 million years ago) was 10° further north.