Weather Eye has never questioned the possible intervention of the Deity in earthly matters. How and why God might choose to interfere, on the other hand, has been the subject of very frequent speculation. In this context, our text for today will be that of the delightful hymn by Cecil Frances Alexander. It first lists:
All things bright and beautiful,
All creatures great and small,
and then goes on to assert:
The Lord God made them all.
The basic thesis we do not dispute - but perhaps the weather may have been the Lordly instrument?
The possibility is encapsulated in the biological principle we know as "Bergmann's Rule". Carl Bergmann, a 19th century German biologist, noticed a curious pattern to the average size attained by warm-blooded animals of the same species.
His "rule" states that the smaller sub-species of a particular species are to be found in the warmer parts of the ecological range, and that the larger races inhabit the cooler districts. In the cat family, for example, the largest is the Siberian tiger, while the biggest bears are found inside the Arctic Circle - most notably, the polar bear.
Bergmann's Rule is assumed to be an evolutionary consequence of the mathematical fact that as a three-dimensional object increases in size, the ratio between its surface area and its volume diminishes.
If, for example, you double the length, width and height of an object, its volume increases by a factor of eight while the surface area grows only by a factor of four. It follows that the bigger an animal happens to be, the smaller the area of skin it has in relation to its bulk. Since body heat is lost mainly through the skin, a large body therefore becomes an advantage in a cold environment where heat conservation is important.
Needless to say, some observers have tried to apply this principle to the human species, pointing out, for example, that an average Finn weighs 154lbs, a Spaniard 132lbs, and a typical Berber of Algeria 124lbs. The average indigenous inhabitant of the Kalahari Desert weighs in at a mere 89lbs.
The inference drawn from these statistics is that average weight increases with distance from the equator - or more specifically, with the decrease in average annual temperature.
But as you might expect, it is more generally accepted that the application of Bergmann's Rule to the human race is highly suspect. Ethnic differences in weight can be more confidently explained, for example, by differences in the kind and quantity of foods available, or by differences in metabolic rates.