Researchers in Spain and Norway reported in the periodical
Nature they had found tree-like growth rings on the bones of
mammals, a characteristic that until now was thought to be
limited to cold-blooded creatures and dinosaurs. They also found
proof that dinosaurs probably had a high metabolic rate to allow
fast growth another pointer of warm-bloodedness. "Our results
strongly propose that dinosaurs were hot-blooded," lead author
Meike Koehler of Spain's Institut Catala de Paleontologia told
AFP. If so, the findings should punctual a rethink about
reptiles, she said. Modern-day reptiles are cold-blooded,
meaning they cannot control their body temperatures through
their own metabolic system relying instead on outside means such
as basking in the sun. While the dinosaurs may have been hot-
blooded, their other characteristics kept them directly in the
reptile camp, said Koehler. Paleontologists have long noted the
ring-like markings on the bones of cold-blooded creatures and
dinosaurs, and taken them to designat