When I was about 6 or 7 years old, my pestering each fall paid off.

Dad finally took me along on some small game hunting outings.

He, and his best friend Wayne, enjoyed grouse hunting and chasing out some rabbits in some local woodlots.

While riding with them to those spots, their conversations sometimes turned to the deer hunting trips of their friends who had the opportunity to hunt Maine. I remembered how they described bucks weighing over 200 pounds, certainly much bigger than the 120-pound deer they were accustomed to shooting here in Carbon County.

Not knowing the reason for the size difference I just assumed they must eat better food there.

Well, my assumptions were not entirely correct. The truth is that Maine white-tailed deer are considerably larger than their counterparts here in the Times News area.

Carl Bergmann, a German biologist in 1847, first described and detailed his “Bergmann’s Rule.” Basically he developed this theory based on: in colder climates species of mammals, and some birds, in a species, or similar species, will have a bigger body size than those in warmer climates.

Or geographically, those species living in latitudes closer to the Arctic Circle than those in lower latitudes will have bigger body sizes. This doesn’t “hold true” for smaller mammals like ground squirrels or weasels whose smaller sizes allows them to escape cold by moving underground.

Let’s look at some examples.

Polar bears are the largest bear species, followed in size by the brown (grizzly) bear, and black bears are still smaller.

In the deer family, caribou and moose, living much farther north, are larger than their white-tailed deer cousins. And as I mentioned in my introduction, within a species itself, white-tailed deer for example, the northern counterparts are larger than those in warmer areas (areas of lower latitudes.)

This holds true for many birds as well. The snowy owl, living in the coldest area of earth, the Tundra, is the largest owl species.

The great gray owl, living farther south (lower latitudes) is the next largest. In much of the continental U.S., which is farther south, next in size in the great horned owl.

Another bird example is that of the gyrfalcon. The gyrfalcon lives on the Tundra. It is considerably larger than the peregrine falcon which lives and nests a bit farther south where temperatures are a little warmer.

If you are familiar with a willow ptarmigan (all white in winter) that lives on the Tundra, it is larger than its “cousin” the ruffed grouse that live farther south in North America.

Bergmann’s rationale for his rule is as follows: larger animals have a lower surface area to volume ratio than smaller animals, thus they lose less body heat per unit of mass. (Larger animals are more efficient at maintaining their body heat)

I always try to find new information to share about “our nature” and hopefully you can relate to this concept.

For the dedicated “deer hunters,” this can explain why a Maine or Alberta, Canada “white tail” is bigger than our local bucks.

Whether you’re trying to harvest a deer or sitting on your porch looking for any wildlife interactions, keep those eyes and ears open, and learn more and enjoy what we have all around us.

Test Your Outdoor Knowledge. True/False: Only female mosquitoes will bite you or other animals.

Last Week’s Trivia Answer: In 2019 the peregrine falcon was moved from the Endangered List to the Threatened List as its population continues a slow rise.

Barry Reed is a Saturday columnist in the Times News. Contact him at breed71@gmail.com.