Allosaurus hunts the giants
A Jurassic predator with a taste for Stegosaurus and sauropods
Quick facts
- When
- Late Jurassic, about 152 to 145 million years ago
- Size
- About 9.7 m long, roughly 2,700 kg
- Diet evidence
- Stegosaurus fossils with Allosaurus bite marks; scavenged large sauropod remains
- Open question
- Whether it hunted in packs, or attacked large prey alive versus scavenging
What happened
Allosaurus was a large, two-legged predator that hunted across what is now the United States in the Late Jurassic, about 152 to 145 million years ago, growing to roughly 9.7 metres long and 2,700 kilograms, armed with dagger-like, serrated teeth, three-fingered hands, and small horns above its eyes. The Natural History Museum reports direct fossil evidence of its diet: Stegosaurus fossils bearing Allosaurus bite marks, and separate evidence that it scavenged the remains of large sauropods, though experts are not certain whether it regularly killed such enormous prey alive or fed on carcasses it found already dead. Multiple Allosaurus skeletons have also turned up together in the same bone beds, which has led some researchers to wonder whether the species hunted in packs, a hypothesis the museum treats as unresolved rather than settled.
Why it matters
Allosaurus is the direct predator counterpart to the giants of its world: the same Late Jurassic landscape that produced Stegosaurus and the sauropods also produced something built to bring them down, or at least to eat them once they were dead. The uncertainty over pack hunting and scavenging versus active hunting is a reminder that even famous, well-fossilized dinosaurs still carry real, unresolved questions.
How we know
The Natural History Museum's record for Allosaurus gives its Late Jurassic age, its size, teeth, and physical features, and directly states the fossil evidence for bite marks on Stegosaurus remains and scavenging on sauropods, while explicitly noting that whether it attacked large herbivores alive is unresolved. It separately notes the bone-bed groupings behind the pack-hunting hypothesis, also stated as unresolved.
Sources
- Natural History Museum, London. Allosaurus (Natural History Museum Dino Directory) (2024) · Reputable sourcenhm.ac.uk · The domain "nhm.ac.uk" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
- U.S. National Park Service. Allosaurus fragilis (Dinosaur National Monument, U.S. National Park Service) · Reputable sourcenps.gov · The domain "nps.gov" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
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