For my birthday this year, my wife bought me the newish Lego kit Natural History Museum 10326. (Well: actually she bought me a Chinese knock-off for 1/3 the price, but that’s not the point.) It’s a lovely kit and I had a great time building it.

One of the exhibits that you build for the museum is a sauropod skeleton — recognizably a brachiosaur. But as previously documented on this blog, I also have a much larger Lego brachiosaur, built from the piece of the kit Dinosaur Fossils 21320. (That one was also a present from Fiona!)

Here they are, side by side.

So which brachiosaur is more accurately to scale?

Lego is often considered to be in 42:1 scale, based on minifigure height of about 4 cm relative to a typical adult human height of about 1.68 m. (5 feet 6 inches).

I measured the big brachiosaur at 37 cm high from the top of its plinth to the top of the head. At 42:1 scale, that’s 15.54 m. The smaller one is 15 cm tall from plinth to head, which at 42:1 scale is 6.30 m.

The real Giraffatitan mount in the Museum für Naturkunde Berlin is 13.27 m tall (Taylor and Wedel 2013: caption to figure 1). That means that the larger of the two Lego models is much closer to being the right size, relative to the minifigs, than the small one is.

But wait: famously, the Giraffatitan fibula HMN XV2 is 134 cm long compared with 119 cm for the fibula of HMN SII (= MB.R.2181, the mounted specimen) (Janensch 1961: table 16). That’s 1.126 times as long, which indicates it belonged to an animal that stood 13.27 x 1.126 = 14.94 m tall.

That’s 96% the scaled size of the Lego Giraffatitan — which, given the hand-waving involved in the various scalings here, is as near to identical as makes no difference.

In conclusion, m’lud, the large Lego Giraffatitan in the photo above is almost exactly the right size for the largest known individual of that genus, relative to the minifigs and indeed the actual museum.

• Janensch, Werner. 1961. Die Gliedmaszen und Gliedmaszengurtel der Sauropoden der Tendaguru-Schichten. Palaeontographica, suppl. 7(3):177-235.
• Taylor, Michael P., and Mathew J. Wedel. 2013c. The effect of intervertebral cartilage on neutral posture and range of motion in the necks of sauropod dinosaurs. PLOS ONE 8(10):e78214. 17 pages. doi: 10.1371/journal.pone.0078214

doi:10.59350/netrb-zbm84