The Shape of Life . Bones, Brawn and Brains

Wowed by Worms: The Evolution & Ecology of Annelids

There's a good evolutionary reason for growing quickly. Basically, you have to grow fast so you can beat out the predators and be an adult and reach sexual maturity in time to actually reproduce and send your genes on through the gene pool. -- Kristi Curry-Rogers

Video: Curry-Rogers explains how she determines dinosaur growth rates

Paleontologist Kristi Curry-Rogers studies ancient fossils to determine how fast dinosaurs grew. Because the bones of modern day reptiles grow slowly, scientists assumed that dinosaurs grew slowly as well. Experts had estimated that it might have taken up to 120 years for an enormous Apatosaurus to grow to its full length of 70 to 90 feet. To Curry-Rogers, this didn't make sense.

In Bozeman, Montana, she found fossilized Apatosaurus bones and set out to determine the rate at which the dinosaur had grown. Curry-Rogers realized that the interior of the bones contain a record of the animal's growth. She prepared a bone slice one tenth of a millimeter thick and looked at it under a microscope. If the animal had grown slowly, patterns created by the blood vessels in the bone would have been arranged in an orderly fashion.

But Curry-Rogers discovered that placement of the vessels was irregular. She concluded that Apatosaurus might have reached its full size in as few as 10 to 12 years.

Bozeman, MT
	Dr. Kristi Curry-Rogers Biography and Career Q & A