What characterizes the size of gray wolves found in northern regions like Alaska compared to southern counterparts?

Tend to be larger.

The physical morphology of the gray wolf exhibits variation correlated with its geographical distribution, a phenomenon often observed in mammals where larger body size is advantageous in colder climates, aligning with Bergmann's rule. Specifically, wolves inhabiting northern latitudes, such as the massive Northwestern wolves found in areas like Alaska, generally attain greater dimensions than those residing in warmer, southern environments. While males are consistently larger than females across all regions, the northern variants often reach the maximum size parameters cited for the species. This larger stature provides better thermal inertia against extreme cold and may also correlate with the larger prey resources historically available in those northern ecosystems.