Brontosaurus Size Comparison
Brontosaurus 3D Viewer pairs published Late Jurassic figures with a 1.8 m person on screen - length about 21-23 m for B. excelsus (Size vs human uses 22 m), mass about 15-20 tonnes - so the sauropod scale gap stays readable at a glance.
Brontosaurus published figures
The Brontosaurus facts panel and this table disclose published ranges rather than one invented single number; the Size vs human control uses 22 m as the length scale ratio:
| Measure | Figure | Vs a 1.8 m person |
|---|---|---|
| Length | about 21-23 m (B. excelsus); smaller species about 19 m; Size vs human uses 22 m | ~12.2x a person end-to-end at the 22 m scale figure |
| Shoulder height | about 5-6 m at the shoulder for a large adult | ~2.8-3.3x adult standing height |
| Weight | about 15-20 tonnes commonly cited for B. excelsus; some published averages higher | shown as a cross-source range, not one settled midpoint |
| When it lived | ~156-146 million years ago (Late Jurassic, Kimmeridgian-Tithonian), Morrison Formation, western North America; herbivore; Marsh 1879 (B. excelsus); Tschopp, Mateus & Benson 2015 reinstatement | distinct from shipped Apatosaurus after 2015 study |
How the Brontosaurus size-vs-human toggle stays honest
The Brontosaurus model is drawn to a fixed on-screen length so it fits the canvas; the Size vs human control then places a 1.8 m person at the true length ratio used by the viewer (22 m). Tap Size vs human under the canvas to show or hide the scale figure - the comparison is proportional, not a decorative sticker. Published length still spans about 21-23 m for B. excelsus (smaller species about 19 m), so the toggle picks one clear mid-range scale inside that disclosed range.
What a person would see beside a Brontosaurus
What a person would see is a long-necked, long-tailed Morrison Formation sauropod whose body length at the 22 m scale dwarfs a 1.8 m adult end-to-end - turn on the person in the viewer and orbit beside a hind leg to feel the horizontal-back posture. A license-clean CC0 glTF may swap in after first paint; procedural skin color remains an artistic choice if the model load fails. This model is not a fossil-accurate skeleton.
What the Brontosaurus size numbers are not
What these size numbers are not is a claim of one precise length or weight: the Brontosaurus size comparison discloses the about 21-23 m / 15-20 tonne ranges and uses 22 m only for the Size vs human scale; it does not claim Brontosaurus and Apatosaurus are the same after 2015, does not invent soft-tissue accuracy for the procedural body, and this is not a win/lose game. For the control walkthrough see how to view Brontosaurus in 3D. For trade-offs versus phone AR apps see Brontosaurus 3D viewer vs AR apps.
Other dinosaurs to compare
Other dinosaurs in the collection make useful size comparisons too: for the historically linked Morrison sauropod see the Apatosaurus 3D Viewer, or for a longer, lighter diplodocid see the Diplodocus 3D Viewer.
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