09/29/1998 AT 12:00 AM EDT
Paleontologists, who have discovered an e-x-t-r-e-m-e-l-y rare dinosaur's heart in a fossilized skeleton unearthed in South Dakota, may be shifting scientific theories in a profound way. Long thought to be cold-blooded (and we do mean long thought), dinosaurs may actually have been warm-blooded, and therefore capable of engaging in more sustained activities, such as chasing and pursuing enemies, say researchers. "It's truly amazing," Dr. Dale A. Russell of the North Carolina Museum of Natural Sciences (where the grapefruit-sized, 66 million-year-old heart is on display), told The New York Times. "The implications completely floored me." As such, the dinosaur's closest descendent today would be the bird. Barney, take heart. Or wing.