My friend Traumador has made a very good post about New Zealand's dinosaurs in recent study by two Alberta based Paleontologists Snively, and Bell. Of course, all that covered whether the Dinosaurs found in the polar regions of the Earth actually lived there year-round or migrated there the way modern birds do today. One interesting fact, he covered were the fact that small little herbivorous dinosaurs lived in the Poles during the Cretaceous. I've decided to help him out by explaining these cute and resouceful critters. And here they are...
Leaellynasaura: the Polar Hypsilophodont
Allow me to set the scene. As you probably know, the Earth was very different than it is today. For much of the Earth's history when it could support life on land, all the continents were packed together into one big supercontinent called Pangaea. For about 200 million years, most of the Dinosaurs "reign", this supercontinent was together supporting one of the biggest battles ever on the face of the Earth: the Survival of the Fittest. However, once the Cretaceous (145 million years ago-65 million years ago) came along, Pangaea broke up into two supercontinents called Gondwana and Laurasia. The Atlantic Ocean was young and smaller then it is today. North America was split into thirds by an ocean cutting across it. The continents was more recognizable by this time. The setting of our story lies in the Antarctic where Australia was still attached.
The main "character" of this story is a tiny little hypsilophodont called a Leaellynasaura. (Hypsilophodont was a species that first appeared in the Jurassic period.) She wasn't much bigger than a rat today. She lived in the Early Cretaceous in the frozen forests (in the winter) of Antarctica. She was bipedal and were very organized. As the others grazed and went on with their daily business, some stood guard and sounded an "alarm" when a predator was spotted. (e.g. Polar Allosaurus, Koolasuchus) Anyway, they functioned the sameway chipmunks and squirrels do today. They gather food for the harsh winter and store it away. Then, they hibernate, huddling together to stay warm. Their survival was the responsiblities of the alphas of the group. If they died, then there were competitions of dominance to see you the next "chiefs" are. This evolutionary advantage will work for a good several million years. But, it will not save them from extinction later on in the Cretaceous.