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Mononykus

Say it: mə-NON-ik-us

Name means: “single claw”1

Ate: InsectsOdd feathered dinosLate Cretaceous

Mononykus was a tiny, feathered dinosaur that lived in the Late Cretaceous. It had very short arms with one big claw, which it probably used to dig into termite mounds for food. It was about as long as a bicycle and weighed as much as a big cat.2 1

Lived

84 to 66 million years ago4

Late Cretaceous

Fossils found in

Mongolia (Nemegt Formation, Gobi Desert)2 1

Food

Insects2

Length

1 to 1.2 m2 1

Weight

3.5 kg2

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 29 bananas

as long as 2.5 house cats nose to tailas long as 7 bananas end to endabout as heavy as a house catas heavy as 29 bananas

How big was Mononykus compared to YOU?

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cool stuff

Fun facts

Mononykus had a single large claw on each hand, about 7.5 centimetres (3 inches) long. The other two claws were tiny or gone.2

Its inner ear bones look very similar to those of modern barn owls. Scientists think Mononykus might have had a face disc of feathers to help it hear better.2

Mononykus was covered in feathers. Its relative Shuvuuia had feather traces in its fossils, so scientists believe Mononykus did too.2

The first Mononykus fossil was found in 1987 in the Gobi Desert. It was a partial skeleton without a tail and only a few skull bones.2

Mononykus was originally named Mononychus in 1993, but that name was already used for a beetle. So scientists changed it to Mononykus later that year.2

Many museum skeletons of Mononykus are actually based on its close relative Shuvuuia, because early fossils were mixed up.2

AI-made picture of Mononykus — An AI-made picture of how Mononykus 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 Mononykus

?How big was Mononykus?

Mononykus was a very small dinosaur, about 1 to 1.2 metres long and weighing about 3.5 kilograms.2 1

?What did Mononykus eat?

Scientists think Mononykus probably ate insects, like termites, using its big claw to break open mounds. But the exact purpose of its arms is still a mystery.2 3

?Did Mononykus have feathers?

Yes, Mononykus likely had feathers. Its relative Shuvuuia had feather traces in fossils, so scientists believe Mononykus did too.2

?Why did Mononykus have one big claw?

Mononykus had one large claw on each hand, about 7.5 cm long. It may have used them to dig into termite mounds or insect nests, but the exact reason is still debated.2 3

?When did Mononykus live?

Mononykus lived during the Late Cretaceous, about 81 to 68 million years ago.1

?Where was Mononykus found?

Mononykus fossils were found in the Gobi Desert in Mongolia, specifically in the Nemegt Formation.2 1

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Myth buster

Myth: Mononykus was a flightless bird.

Truth: Mononykus was a dinosaur, not a bird. It belonged to the alvarezsaurid group of theropod dinosaurs.2

For dino experts

Scientific name: Mononykus
Named by: Perle et al. 19934
Group: Odd feathered dinos
Family / clade: Alvarezsauridae4
Classification: Theropoda > Alvarezsauridae4
Age of the rocks: 84 to 66 million years (Campanian / Maastrichtian)4
Rock formations: Nemegt, Djadokhta4
Countries: Mongolia4
Fossil records: 6 in the Paleobiology Database4
Also known as: Mononychus (older names now counted as the same animal)4
Discovery: Mononykus was named in 1993 by Perle, Norell, Chiappe and Clark. The first fossil was found in 1987 in the Nemegt Formation of the Gobi Desert, Mongolia.2 1
Still debated: Scientists are not sure exactly what Mononykus used its strange, short arms and big claw for. Some think it dug for insects, but others are still debating.2

Where the facts come from

Mononykus | Natural History Museum (nhm.ac.uk)
Mononykus (en.wikipedia.org)
Mononykus Olecranus, Dinosaur Pictures, Dinosaur Facts - National Geographic | National Geographic (nationalgeographic.com)
Mononykus 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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