TALLAHASSEE, Fla.-Most teenagers have growing pains, but none
probably compared to those of Tyrannosaurus rex as it ascended
to adulthood more than 65 million years ago, according to a
Florida State University researcher. From around age 14 to 18,
T. rex took on about 70 percent of its adult mass, growing from
a 1-ton carnivorous lizard to a bone-crushing, 6-ton dinosaur
eating machine with few rivals in the prehistoric kingdom,
according to FSU biologist Gregory Erickson. At the peak of this
spurt, T. rex grew more than 4.5 pounds a day. Erickson and his
team of paleontologists are the first to establish an accurate
picture of how T. rex accelerated its growth over a relatively
few years to become gargantuan while earlier, smaller relatives
had much slower growth. The scientists did this by counting
growth rings in the bones of T. rex and other members of its
family and calculating the corresponding body size by measuring
the circumference of the femur. The research is featured as the
cover story for the Aug