Dinosaurs were bulk homeotherms

lovethee History

The Cretaceous poles were not at all as nasty as they are today. Walking dinosaur costume Rich forests with small crocodilians and furtles grew around the poles, and tundra was apparently unknown.rs still, the polar winter sun set for days or months on end, depriving ectotherms of their heater. Temperafures became cool, at the least, with occasional light freezes and snowfalls.r6 Just how cool the Cretaceous polar winters were is an increasing subject of dispute, for some believe temperatures were startlingly low, enough for hard freezes-river and coastal ice, and even highland glaciers.r? Realistic dinosaur costume This was not a problem for the crocs and turtles, or small dinosaurs if they were ectothermic. By seeking shelter in bottom muds or dens, they could hibernate through the winter dark, just as alligators used to live through the sharp winters of southern Virginia until they were hunted out. But if the large arctic dinosaurs were bulk homeotherms, they were in a tough spot. Their temperatures declining as the sun daily sank ever lower and disappeared, and too big to den in for the winter, they could not hibernate exposed to a winter full of chiling, breezy rains and wet snow storms. After all, wind-chill factors and evaporation could have driven their body temperatures to below freezing, a lethal situation even if the milder climatic scenarios are accepted.

 

confirmation that really big ectotherms could not tolerate such conditions comes from the giant phobosuchid crocodilians of the Late Cretaceous. Animatronic dinosaur costume Relatively common in the southern United states, they become rare in wyoming and Montana, and are absent from Alberta up to the arctic. All these formations were wellwatered and had plenty of big rivers for the giant crocs. Dinosaur costume for adult The phobosuchids were too big to hibernate, however, and it may have been that the winter climate of Montana and wyoming was just able to support them. The Montana-Wyoming border was thgn at about 55″N, and the sun would be up for about five hours arld rise eleven degrees above the horizon at winter solstice. Further north, it was apparently too cold and sunless to keep really big ectotherms going.