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Zavacephale

Say it: ZAH-vah-SEF-ah-lee

Name means: “origin head”1

Ate: PlantsDome-headsEarly Cretaceous

Zavacephale was a small, dome-headed dinosaur that lived in what is now Mongolia. It had a thick, rounded skull like a helmet, and it probably used it for head-butting contests. It is one of the oldest and most complete dome-headed dinosaurs ever found.1 2

Lived

120 to 100 million years ago5

Early Cretaceous

Fossils found in

Khuren Dukh Formation, Dundgobi Province, Mongolia1 5

Food

Plants5 1

Length

1 m1

The skeleton is about 1 metre long, but it belonged to a young animal that was still growing.

Weight

5.85 kg1

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 house cats

as long as 2 house cats nose to tailas long as 6 bananas end to endabout as heavy as a house catas heavy as 49 bananas

How big was Zavacephale compared to YOU?

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cool stuff

Fun facts

Zavacephale is the oldest known dome-headed dinosaur, living about 119 to 100 million years ago during the Early Cretaceous.1 2

Its skeleton is about 54% complete, making it the most complete pachycephalosaur ever found.1

It is the first pachycephalosaur to preserve hand bones and a mass of gastroliths (stomach stones).1 2

Unlike later dome-heads, Zavacephale's dome was made mostly of the frontal bone, with little help from the parietal bone.1

The tail of Zavacephale was covered in stiff tendons, but they did not form the 'caudal basket' seen in later pachycephalosaurs.1

The dome grew early in life, before the animal reached full size, which suggests it was important for social displays or head-butting even in young animals.2

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

?How big was Zavacephale?

About 1 metre long and weighed around 5.85 kilograms. That is about the size of a large domestic cat.1 3

?What did Zavacephale eat?

It was a plant-eater. It swallowed small stones called gastroliths to help grind up tough plants in its stomach.4 2

?Did Zavacephale have feathers?

The fossils don't show feathers, so scientists aren't sure. No feathers have been found on any pachycephalosaur.1

?Why did Zavacephale have a dome?

It probably used its thick, bony dome for head-butting contests with rivals, like rams do. The dome may also have been used for display to attract mates.4

?When did Zavacephale live?

It lived about 119 to 100 million years ago, during the Early Cretaceous Period. That makes it the oldest known dome-headed dinosaur.1

?Where was Zavacephale found?

Its fossil was discovered in the Gobi Desert of Mongolia, in the Khuren Dukh Formation.1 3

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Myth buster

Myth: Some people think all dome-headed dinosaurs used their domes for ramming each other like bighorn sheep.

Truth: Scientists are not sure. Zavacephale's dome was well developed even in a young animal, so it might have been for showing off or fighting, but the exact use is still debated.2

For dino experts

Scientific name: Zavacephale
Named by: Chinzorig et al. 20255
Group: Dome-heads
Family / clade: Pachycephalosauria5
Classification: Ornithischia > Pachycephalosauria5
Age of the rocks: 120 to 100 million years (Aptian / Albian)5
Rock formations: Khuren Dukh5
Countries: Mongolia5
Fossil records: 1 in the Paleobiology Database5
Discovery: The fossil was found in 2019 in the Khuren Dukh Formation of Mongolia, and it was formally named by Tsogtbaatar Chinzorig and colleagues in 2025.1 2
Still debated: Scientists are still debating how the dome was used, whether for head-butting, display, or something else.2

Where the facts come from

Zavacephale (en.wikipedia.org)
A domed pachycephalosaur from the early Cretaceous of Mongolia | Nature (nature.com)
Best fossil of a dome-headed dinosaur is unearthed in Mongolia | Reuters (reuters.com)
New dome-headed dinosaur species is the most complete pachycephalosaur ever found | Natural History Museum (nhm.ac.uk)
Zavacephale in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.

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