ScienceDaily (June 28, 2011) — Were dinosaurs slow and lumbering, or quick and agile? It depends largely on whether they were cold- or warm-blooded. When dinosaurs were first discovered in the mid-19th century, paleontologists thought they were plodding beasts that relied on their environment to keep warm, like modern-day reptiles. But research during the last few decades suggests that they were faster creatures, nimble like the velociraptors or T. rex depicted in the movie Jurassic Park, requiring warmer, regulated body temperatures.
http://www.sciencedaily.com/releases/2011/06/110628132557.htm