Tuesday, May 29, 2007
More on Big Pigs
The Brown Bear Ursus Arctos lives here and there around the world in the northern hemisphere. In the lower 48, we call the Brown Bear the Grizzly Bear and it usually tips the scales at 450 full grown while the ones on Kodiak Island and on the coast in Russia and Alaska can stand 10 feet tall and weigh 1500 pounds, just as big as a Polar Bear, which like most animals at the poles, are giants compared to the ones lower down (Allen's Rule).
So what accounts for the huge disparity in size? Are the coastal northern bears a different species? (No, not even much of a different subspecies--the DNA is fairly homogeneous). Why are the coastal bears so much bigger then? The obvious answer is the amount of protein they get all their lives with the salmon runs they prey on.
So is that what's making for the giant pigs down south? A constant and ready supply of protein (through stealing catfish feed)? That's my guess.
So what accounts for the huge disparity in size? Are the coastal northern bears a different species? (No, not even much of a different subspecies--the DNA is fairly homogeneous). Why are the coastal bears so much bigger then? The obvious answer is the amount of protein they get all their lives with the salmon runs they prey on.
So is that what's making for the giant pigs down south? A constant and ready supply of protein (through stealing catfish feed)? That's my guess.
# posted by Roger Fraley @ 7:29 PM 
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There's also an advantage to large animals in cold weather. Mass (and heat generation) rise with the cube of the length, while surface area (and cooling rate) rise with the square of the length. Large animals require less food per mass to maintain their body temperatures than small animals do.
Thus, Allen's Rule. On the other end of the spectrum, I caught a shrew one day and starved it to death in a few hours. I didn't know.
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