Brontosaurus, once considered synonymous with Apatosaurus, is a genus of large sauropod dinosaurs known for their long necks, massive bodies, and whip-like tails. They inhabited the Late Jurassic period's floodplains in North America, thriving in lush environments. These gentle giants were herbivorous, feeding on vegetation high above the ground.

Brontosaurus species, including Brontosaurus excelsus, Brontosaurus parvis, and Brontosaurus yahnahpin, were native to the western regions of North America during the Late Jurassic period. This includes areas that are now part of the United States, specifically the Morrison Formation, which spans across parts of states such as Wyoming, Colorado, Utah, and Oklahoma.

During the Late Jurassic, the environment of the Morrison Formation was characterized by a semi-arid climate with distinct wet and dry seasons. This region featured a mix of floodplains, river channels, and open woodland areas, which supported a diverse array of plant life including ferns, cycads, conifers, and ginkgoes.

Brontosaurus species were large herbivorous dinosaurs that likely browsed on high vegetation due to their long necks, feeding on leaves and other plant materials. They played a significant role in their ecosystem as mega-herbivores, influencing vegetation patterns and interacting with other species, both plant and animal.