Chilly Dinos..

[Technomancer]

http://www.smithsonianmag.com/history-archaeology/polar-dinosaurs-200712.html?c=y&page=1

It's an interesting article about arctic/antarctic dwelling dinosaurs. I'd be curious to know of any climate modelling from that time period.

[mitsuki lover]

Wouldn't that be before the poles started to freeze over and they were more of a tropical climate?

[EricTheFred]

Wouldn't that be before the poles started to freeze over and they were more of a tropical climate?

Tropical, no. The leading climate model for the time period has the poles on the colder side of 'Temperate', having very harsh winters but verdant summers. Kind of like the midwestern Canadian provinces like Manitoba. The debate among paleontologists concerning how the dinosaurs of the region survived what would have still been very difficult winters (since they still had six months of night and six months of day) is divided between those contending they were warm-blooded like birds and hibernated through the winters like many arctic mammals, and those contending they were migratory and headed for warmer climes when the days started getting short.

[Technomancer]

True, although some (warm-blooded) animals make it through the winter without hibernating. Some small mammals remain active throughout the winter, as do several kinds of birds. A small enough animal might be able to forage enough food to survive the long winter, whereas larger animals would likely be forced to migrate. Granted, these animals do have natural insulation, but some of the dinosaurs are believed to have had some form of proto-feathers.

[EricTheFred]

True, although some (warm-blooded) animals make it through the winter without hibernating. Some small mammals remain active throughout the winter, as do several kinds of birds. A small enough animal might be able to forage enough food to survive the long winter, whereas larger animals would likely be forced to migrate. Granted, these animals do have natural insulation, but some of the dinosaurs are believed to have had some form of proto-feathers.

I'm not exactly an expert (D***it Jim, I'm an Engineer, not a Paleontologist!) but I seem to recall the preference for hibernation as a survival method comes from the size of the creatures in question. Warm-bloodedness requires lots of fuel. IIRC, they occasionally discuss whether wooly mammoths and wooly rhinos may have hibernated as well, because of this same issue. A big animal might have simply hunkered down and let the snow cover them up. Combining the snow insulation (like an igloo) with their insulation (fur or feathers) and a good supply of stored fat in their huge bodies might have been the best survival method available.

There's a modern example of an animal doing exactly this, of course, being the Polar Bear. However, there are no living examples that hibernate and are related to the animals in question, so the debate continues to rage.

[mitsuki lover]

Since birds are supposed to be descended from dinosaurs I can see where the idea that the dinos might have migrated comes from.Though since the shape of the world was different back then it might be a bit harder to
figure out the migration patterns.I.e. when compared to the shape of the present day Earth.
btw:Is is possible that the migration patterns of bird could be based on any
hypothetical migration routs of the dinos?

[Technomancer]

I don't think the dinosaur-avian connection ought to be thought of as the source of any migratory habits. Both mammals and fish also exhibit seasonal migration patterns for example. Most likely, if polar dinosaurs did migrate it simply had to do with following a shrinking food supply, in much the same way that modern grazers such as caribou will migrate. As far as modern bird migration patterns go, it seems more likely that these developed well after birds themselves took to the air, and grew out of changing climates and topographies.

For example, bird migration patterns from Africa to Europe most likely grew out of fairly short, seasonal travels. As the climate changed, and the Sahara came into being, these trips became longer and longer. Because of the slowness of these changes however, the instinctual need to migrate was retained even as the trip itself became more and more arduous (see for example, Sir David Attenborough's "The First Eden").