Dinosaurs - hot or cold?

I was under the impression that the reason for nasal turbinates (?) was to prevent loss of moisture and to warm incoming air - like the Neanderthal face according to Coon. Incidentally, perhaps that would be a reason for a large size- the old surface to volume argument. Something as small as an insect pretty well has to have an exoskeleton. To digress from paleontology, Bernd Heinrich's _The Thermal Warriors_ is a fascinating discussion of heat problems in insects. Don't know that there are any principles there that could be applied to dinosaurs, though. Regards John

The largest living insect is about twice times the size of the smallest living mammal and the heaviest insect is about 4 times as heavy.

The smallest living mammal in the world is the Bumblebee bat. With a body no bigger than a large bumblebee, it has a total length of only 2.9 to 3.3 centimeters,(1.14 to 1.30 inches), and a wingspan of approximately 15 to 16 centimetres (6.9 to 6.3 inches), and a weight of 1.7 to 2.0 grammes (0.06 to 0.07 ounces)

The largest insect alive today is a tropical stick insect whose wingspan averages 13 inches from end to end. The heaviest insect is the African Goliath beetle, who's average weight is a quarter of a pound.

If you use your weights, you get a lot more than 4 times as heavy. 4oz/0.06oz = 67 times as heavy Not trying to be picky ... just clarifying .

Yes, I stand corrected - extremely interesting post, though I didn't mean to start any hares. To get back to paleontology, there are also the insects of the Paleozoic. Still, I think the general thesis stands, that exoskeletons are an advantage for small size, while endoskeletons may be for larger. I suppose extremely large size might make it easier to be 'warm-blooded'.?

I'll have to look this up - drinks nectar or eats fruit, I suppose. I had thought the shrew was smallest. cheers John

My copy of The Encyclopedia of Mammals (1984) mentions what must be the same animal, but calls it 'Kitti's hog-nosed bat'. It agrees that it is the smallest mammal; I always thought some shrew took that honor.

the respitory turbinates are not a be-all-end-all proof of ectothermy or endothermy. Greg Paul has shown that using the exact same testing methods as Ruben et all, the kiwi would not qualify as an ectotherm.

-Betty Cunningham

You mean the turbinates were missing or that they had no attachment shelves in the cranium or what?

Tom

GSP has posted several long threads on this in great detail on the Dinosaur Mailing list. For the entire details, go here: OUR FREIND, THE KIWI http://www.cmnh.org/fun/dinosaur-archive/1996Nov/ 0281.html with follow-up postings here: http://www.cmnh.org/fun/dinosaur-archive/1998Jan/ msg00500.html and here: http://www.cmnh.org/fun/dinosaur-archive/1998Jan/ msg00550.html

-Betty Cunningham

On 2 Apr 1998 17:53:01 GMT, Christine Janis

(Snip)

I think #4 is the key point. All paleoclimatic indicators for the late Jurassic and Cretaceous periods suggest a very high humidity with an abundance of water. (Vegetation was most similar to modern rain forest conditions, for example.) Under such conditions, water conservation probably wasn't much of a problem.