Nanuqsaurus hoglundi, the “polar bear lizard”, is barely two-thirds the size of Tyrannosaurus rex. It is the only tyrannosaur ever found outside temperate regions.

The discovery happened in Alaska’s North Slope back in 2006, when Anthony Fiorillo of the Perot Perot Museum of Nature and Science in Dallas, Texas, took a few basketball-size rocks back home.





The rocks were largely ignored at the Perot as Paleontologist Ron Tykoski was focused on the horned dinosaur Pachyrhinosaurus perotorum. Until the moment they realized that there were score marks and teeth sunken into their 4-ton herbivore, indicating the existence of a predator in the area.





When the team reexamined the rocks, they found teeth consistent with the ones found in P. perotorum, alongside fragments of the skull and jaw. Further comparison determined that the partial skull belongs to a dwarf-sized tyrannosaur, the first of its kind to be found from the region.