Plesiosaurus Size Comparison
Plesiosaurus 3D Viewer pairs published Early Jurassic figures with a 1.8 m person on screen - length about 3.5 m (NHM; historical range about 3-5 m), weight about 90 kg on the conservative figure - so the scale gap stays readable at a glance.
Plesiosaurus published figures
The Plesiosaurus facts panel and this table disclose published ranges rather than one invented single number; the Size vs human control uses 3.5 m as the length scale ratio:
| Measure | Figure | Vs a 1.8 m person |
|---|---|---|
| Length | about 3.5 m (Natural History Museum); Britannica about 4.5 m; EBSCO 3-5 m range; Size vs human uses 3.5 m | ~1.9x a person end-to-end at the 3.5 m scale figure |
| Weight | about 90 kg (EBSCO-attributed conservative figure); some popular sources up to roughly 450 kg for large individuals | shown as a cross-source range, not one settled point |
| Body plan | neck far longer than the body; tiny head; short torso; four broad paddle flippers; short tail with no vertical fluke | distinct from shipped Mosasaurus (long body + short neck + tail fluke) |
| Vs Mosasaurus | Plesiosaurus ~3.5 m Early Jurassic Sauropterygia; Mosasaurus Late Cretaceous Mosasauria, much larger in this collection | both marine reptiles, neither dinosaurs; different lineages |
| When it lived | ~199-175 million years ago (Hettangian-Toarcian), Early Jurassic; named Conybeare & De la Beche 1821; Mary Anning near-complete 1823 Lyme Regis find; NHMUK PV R.1330 | predates the word dinosaur (coined 1842) |
How the Plesiosaurus size-vs-human toggle stays honest
The Plesiosaurus 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 (3.5 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 3-5 m across sources, so the toggle picks one clear scale inside that disclosed range.
What a person would see beside a Plesiosaurus
What a person would see is a short-torso marine reptile whose neck stretches far beyond the body toward a tiny head - turn on the person in the viewer and orbit along the neck to feel how the silhouette sits relative to the scale figure. It is smaller than the already-shipped Mosasaurus in this collection. Skin color is an artistic reconstruction; the model is procedural with no free-licensed Plesiosaurus glTF re-hosted yet.
What the Plesiosaurus size numbers are not
What these size numbers are not is a claim of one precise length or weight: the Plesiosaurus size comparison discloses the NHM 3.5 m and EBSCO ~90 kg figures alongside the wider 3-5 m and up-to-~450 kg ranges and uses 3.5 m only for the Size vs human scale; it does not claim Plesiosaurus was a dinosaur, does not invent a settled swan-like swimming posture, no free-licensed Plesiosaurus glTF is re-hosted yet so the viewer stays procedural, and this is not a win/lose game. For the control walkthrough see how to view Plesiosaurus in 3D. For trade-offs versus phone AR apps see Plesiosaurus 3D viewer vs AR apps.
Other animals to compare
Other animals in the collection make useful size comparisons too: for the Late Cretaceous marine reptile with a short neck and tail fluke see the Mosasaurus 3D Viewer, or for another Early Jurassic coastal find story see related Lyme Regis context on the Plesiosaurus facts panel.
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