Wednesday, July 27, 2011
Human-like body temps for dinos: dental analysis reveals how warm sauropod blood was
Scientists have done the paleontological equivalent of jamming a thermometer up a giant reptile's rear end. Reporting online June 23 in Science, researchers say the huge, four-legged dinosaurs known as sauropods would have registered a body temperature similar to that of any modern Homo sapiens.
The work provides perhaps the best glimpse yet at dinosaurs' internal temperature, a key factor in understanding their metabolism. The findings measure some 4 to 7 degrees Celsius cooler than one theory of dinosaur growth has suggested.
Once thought to be cold-blooded and sluggish, dinosaurs got a reputation makeover in the 1960s and 1970s as active, possibly warm-blooded creatures. But scientists still don't agree on exactly how dinosaurs exchanged heat with their surroundings and how warm or cold they might have been inside.
To tackle this question, a research team led by Rob Eagle of Caltech decided to look at sauropods, the biggest land animals that ever lived. Eagle's adviser, John Eiler, had invented a way to tease out body temperature by studying the number of chemical bonds formed between rare versions of carbon and oxygen in growing teeth and bone. More of those bonds form at lower temperatures, so fossilized teeth can reveal how warm it was inside the living animal.
Eagle's team analyzed teeth of several sauropod species excavated in Tanzania, Oklahoma and Wyoming. The creatures' internal temperatures clocked in between 36[degrees] and 38[degrees] Celsius. That's warmer than cold-blooded creatures like crocodiles, cooler than birds, and just about the range of modern mammals.
Other scientists have suggested that sauropod body temperature could have reached 40[degrees] or even higher, simply because of the sheer amount of the dinosaurs' flesh. The new work fits with other recent evidence suggesting that sauropods and modern mammals were about the same temperature, says Luis Chiappe, a paleontologist at the Natural History Museum of Los Angeles County.
Witze, Alexandra. "Human-like body temps for dinos: dental analysis reveals how warm sauropod blood was." Science News 16 July 2011: 10. Gale Power Search. Web. 27 July 2011.