Tyrannosaurus Rex may have been three species, scientists say

Geologist Bill Simpson cleans Sue, a 67-million-year-old Tyrannosaurus Rex on display at the Field Museum in Chicago. The species may have been one of a few tyrannosaurus species that evolved over their million-or-so years on Earth. Photo: Scott Olson/Getty Images

With its immense size, dagger-like teeth and sharp claws, Tyrannosaurus Rex was a fearsome predator that once terrorised North America. Now researchers studying its fossils have suggested the beast may not have been the only tyrannosaurus species.

Experts studying remains thought to belong to T-Rex have suggested their variation shows evidence of not one species but three.