damn_registrars writes "Using rare isotope ratios, a geology team at CalTech has determined body temperatures of sauropod dinosaurs. Their work finds temperatures that are roughly in line with modern mammals for body temperature. However, as the authors point out, this does not on its own confirm dinosaurs to be entirely warm-blooded, as they may have kept these temperatures by sheer mass. The peer-reviewed paper is available online in PNAS. You can also get the article free through pubmed."