Brachiosaurus

Brachiosaurus is an iconic sauropod that roamed North America during the Late Jurassic period, famously discovered in the Morrison Formation of Colorado. Its name reflects its unusually long upper arm bones, giving the back a sloping posture that elevated the base of the neck far above the hips. Unlike long, low diplodocids of its day, Brachiosaurus was an obligate high browser, equipped to strip leaves from high coniferous canopies. Adult individuals measured between twenty-four and twenty-eight metres long and weighed somewhere between thirty-five and fifty-eight tonnes. Its vertebrae were deeply excavated with air sacs connected to the respiratory system, significantly lightening the colossal skeleton without sacrificing structural integrity. It shared its semi-arid floodplain home with diverse dinosaurs including Stegosaurus, Allosaurus, and Camarasaurus.

Its front legs were longer than its hind legs, reversing the typical sauropod body plan.

Where and when

Brachiosaurus lived in the Late Jurassic, from 154 to 145 million years ago (Kimmeridgian-Tithonian age). Its remains come from United States, in the Morrison Formation.

The numbers

Length 26 m (estimates run from 24 to 28 m). Mass about 45 t. Hip height about 5 m. That is 15.3 human-lengths, or 2.32 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, hip height.

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