Repenomamus
Name means “Reptile mammal”
🚫 Not a dinosaur!
Repenomamus was a mammal with fur that fed its babies milk, like badgers or dogs today. Mammals lived at the same time as dinosaurs, but they are on a completely different branch of the animal family tree.
Repenomamus was a furry mammal about the size of a badger — and it ate baby dinosaurs! It lived in China during the age of dinosaurs.
Repenomamus was a gobiconodontid mammal from the Early Cretaceous of northeastern China and one of the largest mammals of the Mesozoic. Fossils showing dinosaur bones in its stomach, and one locked in an attack on a Psittacosaurus, prove that some Mesozoic mammals preyed on dinosaurs.
Repenomamus reconstruction.jpg — PaleoEquii · CC BY-SA 4.0
Pictures
Spin it in 3D
3D model description: a smooth, rounded model of Repenomamus built from the DinoVerse illustration, showing its overall body shape and proportions. It is not a scan of a real fossil.
About this model
This is a simplified body-shape model, sized to the real animal's length (about 0.8 m). In AR it appears life-size!
It looks best from the side, like the painting it comes from. It is not a fossil scan — museums such as the Smithsonian 3D collection share real fossil scans you can explore.
What might it sound like?
Transcript: Sharp chittering chirps and squeaks
🤔 Nobody knows exactly how dinosaurs sounded
This is a scientific guess. Small and medium-sized living mammals such as badgers, mongooses and opossums make chitters, squeaks and growls, so Repenomamus probably used similar sounds — but its exact voice is unknown.
Voice boxes and soft tissue almost never fossilise, so sound reconstructions use clues: body size (bigger animals make lower sounds), the calls of living relatives (crocodiles boom with closed mouths; birds coo and hiss), and hollow structures such as hadrosaur crests that could have worked like a trumpet.
Sound: synthesised by DinoVerse from these scientific ideas (CC0). It is a creative guess, not a recording.
Food and habits
Carnivore
Meat-eater
How it ate
Pounced on small animals and bit them with strong jaws and pointed front teeth, then gulped down chunks of meat without much chewing.
🔍 How do we know?
- baby Psittacosaurus bones in a stomach
- fossil of one attacking a Psittacosaurus
- sharp front teeth and strong jaws
It ate…
baby Psittacosaurus- lizards
- small mammals
- other small animals
Repenomamus
…and was eaten by
👑 Probably nothing, once fully grown — a top predator or too big to tackle!
Arrows show energy moving up the food chain: from food to eater.
Watch it walk
Quick facts
| 📏 Length | 0.5–1 m (2–3 ft) |
|---|---|
| ↕️ Height | 0.2–0.3 m (0–1 ft) |
| ⚖️ Weight | 4–14 kg (10–30 lb) |
| ⏳ When it lived | 125–123 million years ago (Early Cretaceous) |
| 📍 Fossils found | Lujiatun beds, Yixian Formation, Liaoning, China |
| 🔎 Discovered | 2000 by Li Jinling and colleagues |
| 🧬 Group | Mammals — Synapsida › Therapsida › Cynodontia › Mammalia |
Where scientists disagree, we show a range. Sizes are for adults.
How big was it?
Where and when
- 📍 Lujiatun beds, Yixian Formation, Liaoning, China (Asia)
Lived 125–123 million years ago
That's about 124 million years before you were born! Humans have only existed for about 0.3 million years.
See it on the big timeline →Did you know?
- 1Repenomamus was a mammal that ate baby dinosaurs!
- 2It was about the size of a badger or a small dog.
- 3It had fur, just like a cat or a dog.
- 4One amazing fossil shows a Repenomamus biting a dinosaur bigger than itself!
- A 2005 study described a specimen of R. robustus with the bones of a juvenile Psittacosaurus in its stomach region, the first direct evidence of a mammal eating a dinosaur.
- In 2023 researchers described a fossil, buried by a volcanic mudflow, of R. robustus gripping and biting a Psittacosaurus about three times its weight, suggesting it actively hunted rather than only scavenging.
- The larger species, R. giganticus, may have weighed over 12 kg, challenging the idea that all mammals in the age of dinosaurs were tiny, shrew-like creatures.
- Repenomamus belongs to the eutriconodonts, an extinct branch of mammals that is not closely related to today's marsupials or placental mammals.
Myth vs fact
❌ MythAll mammals in the age of dinosaurs were tiny and spent their lives hiding from dinosaurs.
✅ FactRepenomamus was badger-sized and sometimes hunted dinosaurs itself.
❌ MythRepenomamus was a dinosaur.
✅ FactIt was a mammal, with fur and milk-fed babies, on a completely separate branch from dinosaurs.
Mini quiz
1. Is Repenomamus a dinosaur?
2. What did scientists find in a Repenomamus stomach?
3. About how big was Repenomamus?
Related animals
Psittacosaurus
CeratopsianEarly CretaceousHerbivore
Yutyrannus
TheropodEarly CretaceousCarnivore
Microraptor
TheropodEarly CretaceousCarnivore
Not a dinosaurDimetrodon
SynapsidEarly PermianCarnivore
Media on this page
- Repenomamus reconstruction.jpg — PaleoEquii · CC BY-SA 4.0
- Fern in forest by I. Levitan (1895, N. Novgorod).jpg — Isaac Levitan · Public domain
- Repenomamus simplified 3D model — DinoVerse (generated from original artwork) · CC0 1.0
- Repenomamus reconstructed call (synthesised) — DinoVerse (synthesised) · CC0 1.0
- Repenomamus-Paleozoological Museum of China.jpg — Morosaurus millenii · CC BY-SA 4.0
- Psittacosaurus and Repenomamus life restoration - Han et al 2023.png — Michael Skrepnick · CC BY 4.0
- Psittacosaurus lujiatunensis-Repenomamus robustus pair (WZSSM VF000011) locked in mortal combat.webp — Authors of the study: Gang Han, Jordan C. Mallon, Aaron J. Lussier, Xiao-Chun Wu, Robert M · CC BY 4.0
- Repenomamus BW.jpg — Nobu Tamura (http://spinops.blogspot.com) · CC BY 3.0