Elmer S. Riggs Riggs' assistant, H. William Menke, found the first known skeleton of the giant sauropod dinosaur "Brachiosaurus altithorax" from near Grand Junction, Colorado. At the end of the 1900 field season Riggs' found a specimen of "Apatosaurus" near Fruita, a few miles from the Brachiosaurus site. This specimen was excavated during the 1901 field season, and was put on display in 1908 at the Field Museum. From these specimens he named "Brachiosaurus" and Brachiosauridae, and presented evidence that "Apatosaurus" and "Brontosaurus" were the same genus of dinosaur. He also proposed that sauropods were terrestrial animals, based on their limb structure, but
Apatosaurus the time of the creature's maturity. This was first noted in 1903 and again in 1936. Long-bone histology enables researchers to estimate the age that a specific individual reached. A study by Eva Griebeler etal. (2013) examined long-bone histological data and concluded the "Apatosaurus" sp.SMA0014 weighed , reached sexual maturity at 21years, and died aged 28. The same growth model indicated "Apatosaurus" sp.BYU 601–17328 weighed , reached sexual maturity at 19years, and died aged 31. Compared with most sauropods, a relatively large amount of juvenile material is known from "Apatosaurus". Multiple specimens in the OMNH are from juveniles of an