Brachiosaurus was a massive herbivorous dinosaur with a long neck, small head, and large, powerful legs. It lived during the Late Jurassic period in what is now North America. Its unique limb structure, with longer front legs than hind legs, allowed it to reach high vegetation.

Brachiosaurus fossils have been predominantly found in North America, specifically in the Morrison Formation, which spans across the western United States. There have also been potential Brachiosaurus findings in Africa, particularly in the Tendaguru Formation in Tanzania, though these may belong to related genera.

The environment of the Morrison Formation during the Late Jurassic period, approximately 154 to 150 million years ago, was semi-arid with distinct wet and dry seasons. It was characterized by floodplains, river deltas, and open woodlands, providing a mix of lush vegetation and open spaces.

Brachiosaurus was a large, herbivorous dinosaur that likely fed on high-growing vegetation, such as conifers and cycads. Its long neck allowed it to reach foliage other herbivores could not, occupying a niche as a high-browser in the ecosystem.