Nanotyrannus Facts
| Diet | Carnivore |
| Height | 2m |
| Length | 5m |
| Weight | 1 tonnes |
| Speed | 25 km/h |
| Environment | Land |
| Era | Cretaceous |
| Period | Late Cretaceous |
| Type | Theropod |
| Location | North America |

| Diet | Carnivore |
| Height | 2m |
| Length | 5m |
| Weight | 1 tonnes |
| Speed | 25 km/h |
| Environment | Land |
| Era | Cretaceous |
| Period | Late Cretaceous |
| Type | Theropod |
| Location | North America |
Nanotyrannus is one of palaeontology's most hotly debated theropod dinosaurs, having sparked decades of scientific controversy. Originally described in 1946 from a single skull found in Montana's Hell Creek Formation, this small tyrannosaur lived during the final million years of the Late Cretaceous period, 67 to 66 million years ago, right up until the asteroid impact that ended the age of dinosaurs.
At roughly 5 metres long and 2 metres tall at the hip, Nanotyrannus was considerably smaller than its famous relative Tyrannosaurus rex, weighing approximately 1 tonne. This theropod possessed the classic tyrannosaur body plan: powerful hind limbs built for speed, relatively small arms with two-fingered hands, and a massive skull filled with sharp, serrated teeth designed for slicing through flesh and bone.
As a carnivore, Nanotyrannus would have hunted the rich variety of prey available in the lush, subtropical forests of Late Cretaceous North America. Its smaller size and likely greater agility compared to adult T. rex may have allowed it to pursue different prey, possibly including smaller dinosaurs, mammals, and other vertebrates that larger tyrannosaurs couldn't easily catch.
The greatest mystery surrounding Nanotyrannus is whether it truly represents a separate species or is actually a juvenile T. rex. Many modern palaeontologists favour the latter interpretation, suggesting that the supposed distinguishing features of Nanotyrannus are simply characteristics of young tyrannosaurs that changed as they matured into the giants we know as T. rex.
Nanotyrannus had a proportionally longer, narrower skull than adult Tyrannosaurus rex, with more teeth that were less robust. The skull showed a distinctive ridge above each eye socket and larger eye sockets relative to skull size, giving it potentially better vision than its larger relatives.
As a smaller theropod, Nanotyrannus likely relied more on speed and agility than brute force when hunting. It may have been capable of pursuing faster, more nimble prey that larger tyrannosaurs couldn't catch, potentially filling a different ecological niche in its prehistoric ecosystem.
Nanotyrannus has appeared in several dinosaur documentaries and books, often presented as T. rex's smaller cousin, though its uncertain status means it receives less attention than other tyrannosaurs.
Nanotyrannus was first described by Charles W. Gilmore in 1946. The original fossils were discovered at Hell Creek Formation, Montana, USA.