In an announcement that conjured up thoughts of the movie "Jurassic Park," researchers revealed they had recovered soft tissues that resemble blood vessels and even cells from a 70-million-year-old Tyrannosaurus rex.
They don't know if they'll be able to recover DNA — the blueprint to life that was the key to recreating the giant animals in the fictional film.
But scientists are excited about the chance to learn more about what went on inside the great beasts, perhaps to learn what they were really made of.
If they can isolate proteins from the material, they may be able to learn new details of how dinosaurs lived, said lead researcher Mary Higby Schweitzer of North Carolina State University.
"We're doing a lot of stuff in the lab right now that looks promising," she said in a telephone interview.
The soft tissues were recovered from the thighbone of a T. rex, known as MOR 1125, that was found in a sandstone formation in Montana. The dinosaur was about 18 years old when it died.
The bone was broken when it was removed from the site. Schweitzer and her colleagues then analyzed the material inside the bone.
"The vessels and contents are similar in all respects to blood vessels recovered from ... ostrich bone," they reported in a paper bring published Friday in the journal Science.
Because evidence has accumulated in recent years that modern birds descended from dinosaurs, Schweitzer said she chose to compare the dinosaur remains with those of an ostrich, the largest bird available.
Brooks Hanson, a deputy editor of Science, noted that there are few examples of soft tissues, except for leaves or petrified wood, that are preserved as fossils, just as there are few discoveries of insects in amber or humans and mammoths in peat or ice.
Soft tissues are rare in older finds. "That's why in a 70-million-year-old fossil it is so interesting," he said.