Brachiosaurus is one of the most recognizable and imposing dinosaurs, frequently depicted in popular culture. This long-necked sauropod is known for its immense size and distinctive towering posture.
Defining Physical Traits
Brachiosaurus was an enormous creature, with an estimated length of 59 to 72 feet (18 to 22 meters) and a height reaching 41 to 49 feet (12.5 to 15 meters). Its weight ranged from 28.3 to 46.9 metric tons (31.2 to 51.7 short tons), making it one of the heaviest dinosaurs. It had an exceptionally long neck, held in an upright, giraffe-like posture. Its front limbs were notably longer than its hind limbs, a feature from which its name, meaning “arm lizard,” is derived.
Its head was relatively small. The skull featured a wide muzzle, thick jawbones, and peg-like or spoon-shaped teeth for stripping vegetation. Its nostrils were unusually positioned high on top of its head. Air sacs connected to its lung system invaded the vertebrae and ribs, significantly reducing its body density. This adaptation, along with a robust vertebral structure, supported its immense frame and towering height.
Diet and Habitat
Brachiosaurus was a herbivore. Its height and long neck allowed it to browse high foliage, reaching leaves and branches inaccessible to most other dinosaurs. This feeding strategy likely focused on conifers, ginkgos, and cycads. An adult Brachiosaurus needed to consume an estimated 200 to 400 kilograms (440 to 880 pounds) of plant matter daily.
Its teeth were effective for stripping leaves but not for chewing, suggesting Brachiosaurus swallowed vegetation whole. Digestion was aided by gastroliths, or “stomach stones,” which helped break down tough plant material. Brachiosaurus likely lived in herds, providing safety and improving foraging efficiency. Its habitat featured lush vegetation like forests and floodplains, along with rivers and lakes as vital water sources.
Its Place in Earth’s History
Brachiosaurus lived during the Late Jurassic period, approximately 155 to 143 million years ago. Earth’s climate was generally warm and humid during this epoch, with no polar ice caps, fostering widespread lush vegetation. Continents were actively drifting apart, forming new ocean basins and influencing global climate patterns.
Fossils of Brachiosaurus have primarily been discovered in North America, particularly within the Morrison Formation in Colorado, Utah, and Wyoming. Evidence also suggests its presence in Africa, though some fossils initially attributed to Brachiosaurus were later reclassified as Giraffatitan. Brachiosaurus eventually went extinct. While its direct extinction occurred before the major Cretaceous-Paleogene event, environmental shifts and changing resources during the Jurassic-Cretaceous boundary likely contributed to its disappearance around 145 million years ago.