← Rex's Notes
Diplodocus
All neck and tail, very little middle.
Said: dih-PLOD-uh-kus
Era: Jurassic · 154 to 150 million years ago
Diet: Herbivore
Habitat: Open plains of western North America
Size: longer than three school buses end to end.
What it was like
Diplodocus had a tail almost as long as the rest of its body, used for defense and balance. Its long neck held its head out flat, low to the ground, perfect for grazing.
What we know now
An influential 1997 simulation suggested its tail could crack at supersonic speeds, but a 2022 multibody-dynamics study put tip velocities closer to 30 m/s — well below the speed of sound, and the soft tissue likely couldn't have survived the stresses anyway. Peg-like teeth at the front of the mouth, used for stripping leaves rather than chewing. Vertebrae are deeply hollowed, an air-sac-driven weight-saving system shared with modern birds.
Notes
- Held its neck horizontally, not raised like Brachiosaurus.
- Hatchlings grew about a meter per year.
- The skeleton casts gifted to museums by Andrew Carnegie are the basis for many public exhibitions worldwide.