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Brrr, bone chilling paleopolar summers(Polar dinosaur growth and other new papers)



I was completing my energetics chapter for the complete dinosaur recently 
and realized that the climatic data in last year's Spicer and Herman paper in 
triple Paleo is really cool (pun intended) because it does a real number on 
what little is left of the idea that dinosaurs had some form of reptilian 
bradyenergetic ectothermy. It also does in the notion that high latitude 
dinosaurs migrated towards the poles in order to enjoy the beneficent summers. 

The presumption has been that although the polar winters were nasty the 
summers basked under the warming rays of the midnight sun and balmy 
temperatures that even reptiles could operate within. The theory was that it 
would have 
been worthwhile for gigantothermic dinosaurs to come up from winter 
habitats to the south to enjoy this reptilian dinosaurian nirvana. 

Problem with the giganothemic scenario is that on the Alaskan north slope 
inhabited by pachyrhinosaurs, edmontosaurs, tyrannosaurs, ankylosaurs, small 
ornithopods, troodonts etc July average temperatures were in the 50s F, and 
rarely got into the 70s while occasionally dropping into the 40s and 30s. To 
that add that it was cloudy all time most days. Blame it all on that 
Pacific Cold Gyre that blocked warmer air from the south and generated 
perpetual 
clouds. This entirely precludes the reptilian heating by air temperature and 
basking system no matter how large or small the herp is. Which is why there 
has never been found a single bradyenergetic croc or lizard tooth or turtle 
shell piece along with the tachyenergetic dinosaurs, birds and mammals. The 
winters were brutal, with no sun for three months and average January temps 
below freezing, allowing repeat blizzards and the water to ice over (as I 
showed in an illustration in PDW). 

Conditions in Australia look even worse, with evidence for permafrost (at 
least down south). There were polar sauropods that could not migrate north 
because of the ocean down under. 

So dinosaurs great and small similar to those living in warm latitudes were 
living in habitats so harsh that even the summers were chilly and cloudy. 
Yet their bone histology shows that Aussie and Alaskan dinosaurs were growing 
about as fast as those in warmer climes, proof of high energy levels able 
to cope with chronic cold even apparently without surface insulation in 
larger examples. 

There is no way that dinosaurs further south than the North Slope would 
expend all the energy needed to migrate north in the spring-summer when by 
staying put they would enjoy more warmth, more sun, and more food. It would 
have 
been maladaptive. The only dinosaurs that put up with the crappy polar 
summers were the ones already stuck there year round the poor dears. Give them 
your sympathy. 

This means that any "documentary" that shows dinosaur "families" making 
epic journeys from lower latitudes to cavort and gambol in a polar summer 
paradise are as bogus as a bad Car Talk diagnosis. There is no evidence that 
polar dinosaurs migrated long distances, they stuck it out in the winter and 
then ate as much as possible in the warmer months to heat up their bodies and 
try to make it through yet another year. 

And the hypothesis of low metabolic rate dinosaurs is dead, dead, dead. 
Bakker was right. 

GSPaul</HTML>