The size of the carnivorous dinosaurs from Alaska is puzzling. While Nanuqsaurus is smaller than its relatives, another theropod found there, Troodon, appears to be larger than its southern relatives. There is a loose biological trend called Bergmann’s Rule whereby many animals are larger in populations closer to the poles. But not everything follows this trend, Fiorillo says, pointing to grizzly bears in Alaska, which tend to vary in size based more on where they can exploit salmon as a food resource.
