Fun Mononykus Facts For Kids

Joan Agie
Nov 22, 2022 By Joan Agie
Originally Published on Oct 07, 2021
Edited by Christina Harrison
If you've been wondering about what feathered animals look like in prehistoric times, take a look at these Mononykus facts.
Age: 3-18
Read time: 5.6 Min

The Mononykus was a very small dinosaur genus with a classification order under the family of Alvarezsauridae and the clade Theropoda while being closely related to the Shuvuuia. These dinosaurs were said to have lived during the Late Cretaceous period in Mongolia around 70 million years ago.

In 1987, the Mononykus was discovered in the Negemt formation in Mongolia with a partial fossil consisting of fragmentary skull bones with a complete braincase. This Theropod had strange forelimbs consisting of one long claw, unlike two claws of most Alvarezsaurids; with long, slender legs; a tubed snout; and flightless feathers like birds.

The claw is said to have assisted the dinosaur in digging burrows or digging into anthills, suggesting that their diet was mainly insectivorous.

This genus was originally called the Mononychus but was renamed 'Mononykus' because the previous name was already used by a German entomologist to name a beetle.

In addition, a specimen discovered earlier kept in the American Museum of Natural History labeled as a 'bird-like dinosaur' was reported to have been that of the Mononykus, but was later thought to be unlikely.

If you like to keep your mind active by reading dinosaur facts, check out the Avimimus and the Tratayenia.

Mononykus Interesting Facts

How do you pronounce 'Mononykus'?

The word 'Mononykus' is pronounced as Mo-non-e-kus.

What type of dinosaur was a Mononykus?

The classification of this genus belongs to the family Alvarezsauridae, under the clade of Saurischia and Theropoda, and tribe Mononykini.

In which geological period did the Mononykus roam the Earth?

According to science, the Mononykus dinosaur roamed the Earth during the Late Cretaceous epoch.

When did the Mononykus become extinct?

This Late Cretaceous period small dinosaur is said to have gone extinct approximately 70 million years ago.

Where did a Mononykus live?

The fossilized skeleton of this Late Cretaceous period dinosaur was found in the Negemt formation of the Bügiin Tsav locality in the Gobi Desert of Mongolia.

What was a Mononykus' habitat?

Although the exact habitat of the Mononykus olecranus is unknown, some information can be derived from where its skeleton was found. Considering the skeleton was found in the Negemt Formation, the paleoenvironment of this zone suggests that it was well-irrigated by ancient floodplains, streams, and lakes.

The region is estimated to have been semi-forested with tall, thick-wooded conifers such as the Araucariaceae. It is said that the habitat was well-vegetated and rich, supporting several forms of wildlife.

Who did a Mononykus live with?

Not much is known about their lifestyle habits, but based on the paleoecology of their region, they lived among several types of fauna.

How long did a Mononykus live?

The lifespan of this species has not been identified.

How did they reproduce?

Not much is known about the reproduction system of these animals, but it is confirmed that they were oviparous since they belong to the clade of Theropods. In addition, they would have built nests, although no fossilized nest sites or eggs have been found.

Considering they had flightless feathers, they may have been sexually dimorphic suggesting they used visual displays to attract a mate.

Mononykus Fun Facts

What did a Mononykus look like?

Members of this genus have been described based on a partial skeleton consisting of a fragmentary skull bone including a braincase. Mononykus claws were considered quite unusual and strange.

Its stubby forelimbs consisted of one large claw each that measured up to 3 in (7.5 cm) in length, unlike its close relative, the Shuvuuia, which had two claws beside the main, large claw.

A keeled breastbone, fused wrist bone, triangular pubic bone, and different sized toe bones were observed during its analysis. Their skull presented a tubular, long snout that was lined with teeth on the inside and speculated to have been used like modern-day anteaters use their snouts.

They also had long, slender hind limbs, and huge arm and breast muscles.

In addition, fossils were found with feathery structures and upon a microscopic analysis, it was found that they were made of beta-keratin, a basic protein found in feathers of birds. However, these animals could not fly.

This genus consisted of a small, one-clawed Alvarezsaurid which had long hind limbs, feathers, and a tube-like snout.

How many bones did a Mononykus have?

The exact number of bones in the body of the species of this genus is unknown. However, a partial skeleton was found with skull fragments with a complete braincase, distinctive limbs with one claw, hind legs, and some vertebrae.

How did they communicate?

Communication patterns of members of this genus are unknown. Considering they were covered in flightless feathers, there could have been some level of sexual dimorphism, which means they may have interacted through visual display, although vocalization may have also been a way of communication.

How big was a Mononykus?

The Mononykus size is estimated to have been around 3.3-3.9 ft (1-1.2 m) in length which is slightly smaller than a moray eel, and around 5 ft (1.5 m) in height.

How fast could a Mononykus move?

Although not much is known about the speed at which these animals could move or run, the morphology of their hind legs and their length suggests that they were built for fast-running similar to the Shuvuuia.

How much did a Mononykus weigh?

The weight of the members of this Late Cretaceous period genus was approximately 7.7-9 lb (3.5-4 kg) which is around the same as a mature female peacock.

What were the male and female names of the species?

Males and females of this genus did not have separate names and both were called Mononykus olecranus.

What would you call a baby Mononykus?

The baby Mononykus has not been given a specific name through science and can be simply called a juvenile.

What did they eat?

Members of this Theropod genus are speculated to have had an insectivorous diet because of their claws, although it has not been confirmed. They are thought to have used their forelimbs to dig through dirt and anthills and their long snout filled with teeth to extract insects.

These prehistoric animals are said to fill the ecological niche similar to modern-day pangolins, aardvarks, and anteaters.

How aggressive were they?

Whether they were aggressive or not is unknown.

Did you know...

It is speculated that they had only one claw because it was either fused or disappeared because of evolutionary adaptation.

Where were the Mononykus found?

The fossil of this Theropod genus was found in the Negemt formation of the Bügiin Tsav locality in the Gobi Desert of Mongolia in 1987.

Partial remains consisting of fragmentary skull bones along with the braincase were found. It was reported that this genus may have been discovered earlier and was uncovered from the Djadochta formation.

This specimen is housed in the American Museum of Natural History and called a 'bird-like dinosaur', but it was claimed as highly unlikely to have been the Mononykus due to the age and its association with other genera.

What does the name 'Mononykus' mean?

This genus was named as described by Perle et al. and the word 'Mononykus' means 'one claw' referring to claws on its forelimbs.

Here at Kidadl, we have carefully created lots of interesting family-friendly dinosaur facts for everyone to discover! For more relatable content, check out these Gorgosaurus facts and Zuniceratops facts for kids.

You can even occupy yourself at home by coloring in one of our free printable Mononykus coloring pages.


Image one by PaleoNeolitic.

Image two by KJean18.

We Want Your Photos!
We Want Your Photos!

We Want Your Photos!

Do you have a photo you are happy to share that would improve this article?
Email your photos

More for You

See All

Written by Joan Agie

Bachelor of Science specializing in Human Anatomy

Joan Agie picture

Joan AgieBachelor of Science specializing in Human Anatomy

With 3+ years of research and content writing experience across several niches, especially on education, technology, and business topics. Joan holds a Bachelor’s degree in Human Anatomy from the Federal University of Technology, Akure, Nigeria, and has worked as a researcher and writer for organizations across Nigeria, the US, the UK, and Germany. Joan enjoys meditation, watching movies, and learning new languages in her free time.

Read full bio >