Diplodocus carnegii dih-PLOD-oh-kus

"Double beam"

Diplodocus silhouette
You 1.8 m (5.9 ft) tall
Diplodocus 26 m (85 ft) long
15 people holding hands
silhouette · Elihu Guzmán Arroyo (CC-BY) via PhyloPic
Length
26 m (85 ft) — About 26 m long, ~15 tonnes — one of the longest dinosaurs known.
Period
Late Jurassic (155–145 Mya)
Place
North America · Western United States
Food
Herbivore — Low-growing plants, ferns, and possibly conifer needles raked off branches.
Clade
Diplodocidae Dinosauria Saurischia Sauropodomorpha Sauropoda

Diplodocus was a sauropod built like a 26-meter-long suspension bridge. Its neck and tail balanced on hips supported by pillar-like legs, the whole structure held off the ground by tension between front and back. The tail ended in a thin whip — possibly used to make sonic booms to scare off predators, though this is debated.

What we know

  • Longest neck-to-tail of any well-known dinosaur — about 26 m end to end.
  • Skull was small relative to body, with peg-shaped teeth at the front only.
  • Tail had over 80 vertebrae, ending in a thin whip-like tip.
  • Lived in the Morrison Formation alongside Allosaurus, Apatosaurus, Stegosaurus.

What we guess

  • How the neck was held — long debate between high-browsing and low-sweeping postures.
  • Whether the whip tail could break the sound barrier (one paper says yes; many skeptical).
  • How it gathered enough food to feed its enormous body — chewing was minimal, gut fermentation key.