This is correct. Its a proven Biological Fact! Look at it this way. Have you ever seen a tall skinny escimo, or a short fat ethiopian? All about the surface area to volume ratio.
Im about to really start one so get the popcorn:
Its
evolution, and not we came from monkeys evolution which I dont believe in. Its simple evolution like antibiotic resistant bacteria. Ok Here goes. I dont think i have to explain the surface area to volume ratio which dictates that larger mammals are more likely to retain body heat, which in turn gives them a better chance of survival. Over generations if the larger mammals were surviving at a higher % then they were passing down "larger genes" to their offspring. The smaller mammals were more likely to die during harsh conditions so the rate at which their "smaller" genes were being passed down was slightly lower in the gene pool than the "larger" genes. Over long periods of time Genetically those mammals that live in colder climates grew larger in size than those who live in warmer climates. Are there other factors? Absolutely, I dont care if they have the best genes in the pool if they dont get the proper nutrition they will never meet their genetic potential. Are giraffes large? Yes but look at the length of their legs and neck(adaptations). That increases surface area. Elephants, yes but look at the adaptations = large ears- to combat heat. Thats whats cool about nature is that animals adapt despite their genetic makeups find a way to survive. And whats really cool is how the genetic makeup itself slowly changes over time. Just ask any doctor why penicillian is not a fix all antibiotic anymore. A few decades ago if you were sick you got a penicillian shot to fix everything. Its no longer effective because the bacteria adapted by the same basic genetic principals. Hope I made my college genetics professor proud. Shout out to Dr. Otto.
Proven? Where?
Shuter just posted a biological report from Canada saying Bergman's is invalid.
So, is it invalid or does your questionable Eskimo-Ethiopian theory hold water?
Giraffes are close to the equator. They're gigantic.
Elephants are close to the equator. They're enormous.
Dik-Diks are close to the equator. They're so small they could be crammed in an overhead bag for airline travel.
Why aren't penguins the size of cows? They're at the poles and must combat the weather. Bergman's would, theoretically, mean we would have penguins that look like NFL linebackers.