Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: THURSDAY, July 14, 1994 TAG: 9408060001
SECTION: EXTRA PAGE: 8 EDITION: METRO
SOURCE: BOYCE RENSBERGER THE WASHINGTON POST
DATELINE: LENGTH: Medium
The clues are unlikely, however, to settle a debate that began in the 1970s when some paleontologists began to challenge the traditional image of the beasts as sluggish, coldblooded reptiles. The new evidence comes from T. rex bones found in Montana. The specimens are so well preserved that much of the bone has not turned to stone and appears to retain key chemical clues.
Reese E. Barrick and William J. Showers of North Carolina State University sampled the beast's bones and measured the ratio of two naturally occurring isotopes of oxygen that are part of the phosphate compounds normally found in bone.
It is known that the ratio in bone varies with the temperature at which the bone formed. It is also known that bone from deep inside a warmblooded animal will have formed at nearly the same temperature as bone near its surface - the result of a metabolic process that keeps the entire body at a temperature at which muscles can work at peak activity.
Barrick and Showers interpret their evidence - reported in the July 8 issue of Science - as saying that T. rex's bones all formed at nearly the same temperature. Hence, it was warmblooded.
Critics, however, point out that in the 65 million years that the bones lay in the ground, their oxygen isotope ratios could have been altered by groundwater and other substances. Moreover, the animal's bulk alone could have meant that it retained more body heat than any of today's reptiles, which are all smaller. The university researchers are hoping to try their method on bones of an undisputed coldblooded reptile found in the same Montana deposit. If the results show big temperature differences, the T. rex results will be more convincing.
by CNB