An excellent article recently appeared on the blog, Still on the Track. The topic of the blog is sasquatches and Bergmann’s Rule.
Basically, Bergmann’s Rule states that animals of a species (or closely related species) tend to be bigger if they live farther away from the equator. As an example, black bears in Alaska tend to be bigger than those found in Southern California.
The reason for this correlation has to do with staying warm by retaining heat. A mammal’s mass constantly generates heat (mammals are “warm-blooded”), and the only way to let that heat escape into the air is through the animal’s skin. It turns out that mass increases a lot faster than surface area does, so the heat-generating part of the mammal increases faster than the heat-losing part of the mammal.
To visually represent this idea, let’s look at data from a simple example. Starting with a cube that is 1 cm long on each side, we see that the volume (which is directly correlated to its mass) is 1 cubic cm, and the surface area is 6 square cm. If we increase the size of the cube to 2 cm on each side, the volume increases to 4 cubic cm, while the surface area increases to 16 square cm. As the size of the cube increases, the volume increases at a much faster rate than the surface area, as seen in the chart below. This means that in mammals, the mass (which generates a mammal’s heat) increases much faster than its surface area (which loses this heat to the environment).
surface area and volume (mass).
If sasquatches are hypothesized to be real animals, then a possible test would be to see if they conform to the same rules as other mammals do, such as Bergmann’s Rule. In the article mentioned above, author Dale Drinnon took data supplied by George W. Gill and made graphs showing the size trends of sasquatch height estimates from witnesses, as well as recorded footprint lengths. The two gentlemen have shown that sasquatches do seem to conform to Bergmann’s Rule, as would be expected for any natural population of mammals.
Kudos to Mr. Drinnon and Mr. Gill for doing some excellent sasquatch science!