The notion of warm blooded dinosaurs is not new - some of the earlier creatures commonly referred to as “dinosaurs” (basically because the Victorians decided that this is what they were due to them being all fossilised and that) are thought to be closer to mammals.
http://en.wikipedia.org/wiki/Dimetrodonhttp://en.wikipedia.org/wiki/SphenacodontoideaThings like this make the whole warm blooded/cold blooded differentiation with dinosaurs not as black and white as it may have been 30 or 40 years ago. I certainly remember Robert Bakker doing the rounds when
Jurassic Park came out tailking up Tyrannosaurus Rex and arguing (pretty convincingly) that it could not have been cold blooded - it would not have survived, and more so it was so large it
HAD to be warm blooded just to keep those massive leg muscles active.
No one will ever know - unless we can either clone one (very unlikely) or travel back in time to observe. I suspect we’ll find a mixture, but my (uneducated) thoughts are that the bigger ones needed to be warm blooded in some fashion.
