Pregnant T. rex unearthed

Story highlights

  • Rare pregnant Tyrannosaurus rex has been found out West
  • Very difficult to determine gender of fossils

(CNN)Through the years of searching for fossils of the ever-popular Tyrannosaurus rex, locating a pregnant one has been understandably difficult.

But scientists now believe they've located one, determining this particular T. rex that roamed Montana was female.
Traditionally, it's been extraordinarily difficult to figure out a dinosaur fossil's gender.
    Specifically, the researchers from North Carolina State University and the North Carolina Museum of Natural Sciences found a medullary bone in a T. rex femur.