Dino card No. 1238 of 2,027

Nanuqsaurus

Say it: nah-NOOK-sore-us

Name means: “polar bear lizard”1

Ate: MeatTyrannosaursLate Cretaceous

Nanuqsaurus was a small, fierce tyrannosaur that lived in the ancient Arctic, where it was the top predator. It had a short snout and sharp teeth, and it hunted in a world with long, dark winters.1

Lived

72 to 66 million years ago5

Late Cretaceous

Fossils found in

North Slope of Alaska, USA, in the Prince Creek Formation1

Food

Meat2 1

Length

5 to 9 m3 4

initial estimate based on holotype; later studies suggest up to 8, 9 m based on undescribed adult material

Weight

500 kg to 1.9 tonnes3

initial estimate 500, 900 kg; later estimate over 1.9 metric tons based on undescribed adult specimens

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

How long was it?

How heavy was it?

as heavy as 1.5 cars

as long as 2 cars parked in a rowas long as 50 bananas end to endas heavy as 63 big dogsas heavy as 380 watermelons

How big was Nanuqsaurus compared to YOU?

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cool stuff

Fun facts

Nanuqsaurus was small for a tyrannosaur, with an estimated skull length of only 600 to 700 millimeters (about 2 feet) in adults.1

It lived at a paleolatitude of about 80 to 85 degrees north, meaning it experienced months of continuous darkness in winter.3

Its name comes from the Iñupiaq word 'nanuq' for polar bear, because it was a top predator in a cold, seasonal environment.1

Nanuqsaurus had a distinctive skull feature: the first two teeth in its lower jaw were much smaller than the ones behind them, which helped it bite in a unique way.1

It was closely related to the famous Tyrannosaurus rex, but much smaller, possibly because food was scarce in its Arctic habitat.1

The only known fossil is a partial skull, found in 2006, and it was initially mistaken for a different dinosaur called Gorgosaurus.1

AI-made picture of Nanuqsaurus — An AI-made picture of how Nanuqsaurus might have looked, made by a computer from what scientists know. It is a guess: the real animal may have looked different, and nobody knows its true colours.

you asked

Most asked questions about Nanuqsaurus

?How big was Nanuqsaurus?

Scientists first thought it was 5 to 6 meters long, but newer fossils suggest it may have grown to about 7 meters and weighed over 1.9 metric tons.3

?What did Nanuqsaurus eat?

As the top predator in its Arctic home, it likely hunted other dinosaurs like hadrosaurs and horned dinosaurs.3

?Did Nanuqsaurus have feathers?

Yes, it was likely covered in feathers for insulation against the cold.3

?Was Nanuqsaurus a dinosaur?

Yes, it was a theropod dinosaur and a close relative of Tyrannosaurus rex.3

?When did Nanuqsaurus live?

It lived during the Late Cretaceous, about 70 million years ago.4

?Why is it called Nanuqsaurus?

Its name means 'polar bear lizard' in Iñupiaq, because it was the top predator in the ancient Arctic.3

?Could Nanuqsaurus survive in the dark?

Yes, it lived through about 120 days of constant winter darkness each year and likely stayed in the Arctic year-round.3

?Is Nanuqsaurus bigger than a T. rex?

No, it was much smaller. T. rex was about 12 meters long, while Nanuqsaurus was only about half that size.4

Ask Rex about Nanuqsaurus

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Myth buster

Myth: Some people think Nanuqsaurus was a baby Tyrannosaurus rex because it was small.

Truth: Nanuqsaurus was a distinct species, not a baby. It had unique skull features and lived in the Arctic, while T. rex lived further south.1

For dino experts

Scientific name: Nanuqsaurus
Named by: Fiorillo and Tykoski 20145
Group: Tyrannosaurs
Family / clade: Tyrannosauridae5
Classification: Theropoda > Tyrannosauroidea > Tyrannosauridae5
Age of the rocks: 72 to 66 million years (Maastrichtian)5
Rock formations: Prince Creek5
Countries: USA5
Fossil records: 1 in the Paleobiology Database5
Discovery: Nanuqsaurus was named by Anthony Fiorillo and Ronald Tykoski in 2014, based on a partial skull found in Alaska's Prince Creek Formation. The fossil was discovered in the Kikak-Tegoseak Quarry.1
Still debated: Scientists still debate why Nanuqsaurus was so small, with some thinking it was due to limited food in the Arctic, but others suggest it might have been a juvenile or a different factor.1

Where the facts come from

A Diminutive New Tyrannosaur from the Top of the World (pmc.ncbi.nlm.nih.gov)
PBDB Taxon (paleobiodb.org)
Nanuqsaurus (en.wikipedia.org)
Diminutive dinosaur stalked the Arctic | Nature (nature.com)
Nanuqsaurus in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.

Every fact on this page has a number that points to its source. If we got something wrong, sorry, we are dino fans, not a science journal. Tell us at [email protected] and we will fix it.

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