The Sauropod Puzzle

Part of the Dinosaurs: Ancient Fossils, New Discoveries exhibition.

Archival photo of Brontosaurus reconstruction
AMNH Special Collections

In 1905 the American Museum of Natural History displayed the first Apatosaurus skeleton ever assembled. Even then scientists knew how to put together the vertebrae, or neck bones, in the correct order. But the questions expert couldn't answer were: What could this enormous animal do with its neck? Could it reach straight up to the treetops?

It is hard to determine flexibility and movement from handling the bones. The way vertebrae fit together is complicated. And with 15 vertebrae in total, small mistakes in positioning could really add up. Today, scientists use computer models based on exact measurements of the bones to test the range of movement with new precision. This analysis shows that it was impossible for sauropods to hold their necks like giraffes--and that Apatosaurus instead kept a relatively low profile.

Tracing the Past

Kent Stevens taking a measurement with pencil and paper of an Apatosaurus vertebra bone
From AMNH video © 2005


This scientist is tracing mounted vertebrae to obtain accurate measurements for use in computer modeling; digital cameras or surface scanners can also be used. Actual vertebrae (neck, back, and tailbones) are complex structures. But unless a detail affects movement, the bioengineer can ignore it.