Brachiosaurus
Name means “Arm lizard”
Brachiosaurus was a gigantic plant-eater with front legs longer than its back legs. It held its neck up high like a giraffe to munch on treetops.
Brachiosaurus altithorax was a brachiosaurid sauropod from the Late Jurassic Morrison Formation of western North America. Its long forelimbs and steeply sloping back let it browse higher than almost any other animal of its time, and it is known from fewer bones than many famous mounts suggest.
![Scientific life reconstruction of Brachiosaurus: Restoration of Brachiosaurus altithorax. Matches proportions in skeletal diagram by Scott Hartman.[1]](/images/brachiosaurus-life.webp)
Brachiosaurus NT new.jpg — Nobu Tamura · CC BY-SA 4.0
Pictures
Spin it in 3D
3D model description: a 3D model of Brachiosaurus shaped from a scientific life reconstruction painting, with the painting's colours and skin texture wrapped around it. It is not a scan of a real fossil.
About this model
This model is shaped from a scientific life reconstruction by Nobu Tamura: the painting's outline gives the 3D body and the painting itself is its skin. It is sized to the real animal's length (about 20.0 m), so 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: Very deep, slow rumbling bellow, about 4 seconds long
🤔 Nobody knows exactly how dinosaurs sounded
Nobody knows what Brachiosaurus sounded like. Big animals tend to make low sounds, and its relatives, birds and crocodiles, make closed-mouth rumbles, so scientists guess a giant sauropod made very deep booming or bellowing calls.
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
Herbivore
Plant-eater
How it ate
Reached high into the treetops with its upright neck and stripped leaves using broad, chisel-shaped teeth, then swallowed them whole without chewing; its huge gut did the rest of the work.
🔍 How do we know?
- broad chisel-shaped tooth shape
- tooth wear patterns
- very tall shoulders and upward-angled neck suited to high browsing
- plant fossils from the Morrison Formation
It ate…
- Conifer leaves (such as monkey-puzzle relatives)
- Ginkgo leaves
- Cycads
- Tree ferns
Brachiosaurus
…and was eaten by
Allosaurus- Torvosaurus
- Ceratosaurus
Arrows show energy moving up the food chain: from food to eater.
Watch it feed
Quick facts
| 📏 Length | 18–22 m (59–72 ft) |
|---|---|
| ↕️ Height | 9–13 m (30–43 ft) |
| ⚖️ Weight | 28,000–58,000 kg (61,730–127,870 lb) |
| ⏳ When it lived | 155–145 million years ago (Late Jurassic) |
| 📍 Fossils found | Riggs Hill, near Grand Junction, Colorado, USA; Dry Mesa Quarry, Colorado, USA; Morrison Formation, Wyoming, USA |
| 🔎 Discovered | 1900 by Elmer S. Riggs |
| 🧬 Group | Sauropods — Saurischia › Sauropodomorpha › Sauropoda |
Where scientists disagree, we show a range. Sizes are for adults.
How big was it?
Where and when
- 📍 Riggs Hill, near Grand Junction, Colorado, USA (North America)
- 📍 Dry Mesa Quarry, Colorado, USA (North America)
- 📍 Morrison Formation, Wyoming, USA (North America)
Lived 155–145 million years ago
That's about 150 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?
- 1Brachiosaurus could peek into a window on the fourth floor of a building!
- 2Its front legs were longer than its back legs, so its back sloped down like a slide.
- 3It may have eaten hundreds of kilograms of leaves every single day.
- 4Many of its bones were full of air pockets, which made its huge body a bit lighter.
- The type specimen was found by Elmer Riggs's Field Museum team near Grand Junction, Colorado in 1900 and named in 1903; it remains one of the most complete Brachiosaurus skeletons, yet it lacks a skull.
- The famous mounted skeleton in Berlin belongs to Giraffatitan brancai from Tanzania, which was moved out of Brachiosaurus into its own genus in 2009 after detailed comparisons of the vertebrae.
- Mass estimates vary widely, from under 30 tonnes to over 55 tonnes, because the skeleton is incomplete and scientists use different methods, such as limb-bone scaling or 3D volume models.
- Researchers still debate how vertically it held its neck; the neck joints and tall shoulders suggest a raised posture, but blood pressure needed to pump blood to a head 12 m up would have been enormous.
Myth vs fact
❌ MythBrachiosaurus lived in lakes and swamps because it was too heavy to stand on land.
✅ FactIts pillar-like legs, compact feet and air-filled bones show it was fully built for life on land. Underwater, water pressure would have made breathing very difficult.
❌ MythThe nostrils on top of its head worked like a snorkel.
✅ FactThe bony nostril openings were high on the skull, but studies of the soft tissues suggest the fleshy nostrils sat lower, near the front of the snout.
Mini quiz
1. What does the name 'Brachiosaurus' mean?
2. Which legs of Brachiosaurus were longer?
3. Where did Brachiosaurus get most of its food?
Related animals
Diplodocus
SauropodLate JurassicHerbivore
Apatosaurus
SauropodLate JurassicHerbivore
Argentinosaurus
SauropodLate CretaceousHerbivoreAllosaurus
TheropodLate JurassicCarnivore
Sources
Media on this page
- Brachiosaurus NT new.jpg — Nobu Tamura · CC BY-SA 4.0
- Fern in forest by I. Levitan (1895, N. Novgorod).jpg — Isaac Levitan · Public domain
- Brachiosaurus 3D model, shaped from the life reconstruction "Brachiosaurus NT new.jpg" — Nobu Tamura (artwork); 3D shaping by DinoVerse · CC BY-SA 4.0
- Brachiosaurus reconstructed call (synthesised) — DinoVerse (synthesised) · CC0 1.0
- Brachiosaurus mount.jpg — Matt Wedel · CC BY 3.0
- Brachiosaurus NT new.jpg — Nobu Tamura · CC BY-SA 4.0
- Brachiosaurus altithorax.jpg — James St. John · CC BY 2.0
- Brachiosaurus altithorax Mk III Multiview Skeletal.png — Gunnar Bivens · CC BY-SA 4.0