Dinosaurs were related to crocodiles, but they do have important differences.

Dinosaurs are much more closely related to modern day birds. Dinosaurs had gizzards, as birds do. Dinosaurs (at least some) had feathers, and young ones had down. Scaley feet on both dinosaurs and birds are similarly formed.Dinosaur eggs were shelled.

Plus, predator/prey ratios were more similar to modern day warm blooded species than to modern day cold blooded species.

Crocodiles dominated in the time before the rise of dinosaurs. Hip structure is very different. That is the time of the first mammals too. As the dinosaurs got bigger, mammals larger than a big rat, or a small rabbit disappeared.

p.s. enjoy your vacation…please write a letter to DISCOVER or the study authors when you get back, though? =)

I’m no biologist…and I barely know dinosaurs. But I know mechanics and physics cold.

M might be onto something. Looking at the skeleton of a brach..i went on the assumption the animal generated its heat like a cow does, and that there was no outside “coolant”. so how could it effeciently disperse excess heat given the restrictions of area vs volume? The answer…as I said was the animal’s shape.

I put the model through my design program and the answer came back was amazing!

The neck. The neck would work in essence, like a smokestack. The dispersion of heat would be released during 2 phases…when the animal breathes (apparently it had hollow neck bones…so maybe filled with air?) as well as the journey the blood has to travel from the source of heat and back again (in my model, the blood was simulated by a coolant flowsystem of salt water).

Assuming a 20 foot neck, blood would have to travel to the brain…being cooled by exposure to the air at the skin barrier as well as internally by the animal’s breathing…then make 20 foot trek back (subjected to the cooling process again) to the source of heat ( I assumed a modest 40 psi on the coolant…though an animal that size probably had higher blood pressure) Assuming the start of the journey of salt water at 40 C, by the time it returned back, the program calculated a significant drop in temperature of about 12%.

So strictly speaking, from a mechanical point of view, it is plausible that a dinosaur this size could overcome some of the challenges modern mammals face because of the extreme shape of it’s neck. ( for all intense and purposes, i ended up designing a rudimentary air cooled furnace using a salt water heat exchanger)

I suspect the tail played a factor in cooling the animal as well.

I think the researchers might be well served to have a look at something like this from a mechanical point of view. It took me less than 2 hours for my models result to come back…but someone with more time (hey! i’m on vacation!!) might be better able to create something more sustainable to scientific review.

Who knows right?

Very small animals have smooth, straight guts and very simple lung/gill structures, and can fly / become airborne with trivial effort.

So for heat dissipation … the amount of heat generated is relative to mass, while the amount dissipated is relative to surface area. That is why heat dissipation would be more difficult for a bigger animal.

the blood has a LONG way to flow away from the source of heat. so it would dissipoate very nicely before the return trip.

unlike a cow…the blood all stays in a relatively much smaller area.

maybe physics has a role to play given their structure?

If dinos generated heat as cows do, they would have a serious problem getting rid of the extra heat, though–if a cow can overheat from digesting food, think of what would happen to a dinosaur, which has far less relative surface area to shed it from.

here’s a link i found about how cows produce their heat through digestion.

http://www.das.psu.edu/research-extension/dairy/dairy-digest/articles/understanding-heat-stress-in-dairy-cattle

so…any paleantologist out there….here’s a thesis for you. we have a modern example of this effect standing in a field as you drive down the highway.

You know how a compost heap creates its own “heat” as the biomass decays? What if something similar occured in these really large dinosaurs? Because they are constantly feeding…the larger ones may have had a 2nd stomach (or 3rd…) to help with digestion.

What if the amount of food being retained was enough to generate its own heat through the act of digestion?

I know this is anectdotal, but a long time freind who farms cows has always told me that the more you feed a cow, the warmer it gets. and in fact, you can really hurt them by “over stoking” them with food. Like logs on a fire.

So what if these really big dinosaurs did the same thing? the act of digestion generates some (or all) of their heat? Or maybe their metabolism is a hybrid between mammals and dinosaurs?