 Studies of fossilized vegetation suggest that the Alaska North Slope had a maximum temperature of and a minimum temperature of to in the last 35 million years of the Cretaceous (slightly cooler than Portland, Oregon but slightly warmer than Calgary, Alberta).Even so, the Alaska North Slope has no fossils of large cold-blooded animals such as lizards and crocodilians, which were common at the same time in Alberta, Montana, and Wyoming.This suggests that at least some non-avian dinosaurs were warm-blooded.