Apatosaurus the problem of supplying blood to the brain because it would not have been elevated. James Farlow (1987) calculates that an "Apatosaurus"-sized dinosaur about would have possessed of fermentation contents. Assuming "Apatosaurus" had an avian respiratory system and a reptilian resting-metabolism, Frank Paladino etal. (1997) estimate the animal would have needed to consume only about of water per day. A 1999 microscopic study of "Apatosaurus" and "Brontosaurus" bones concluded the animals grew rapidly when young and reached near-adult sizes in about 10years. In 2008, a study on the growth rates of sauropods was published by Thomas Lehman and Holly Woodward.
Apatosaurus of another "Apatosaurus" individual originally described as "Atlantosaurus immanis"; as a consequence, some elements cannot be ascribed to either specimen with confidence. Marsh distinguished the new genus "Apatosaurus" from "Atlantosaurus" on the basis of the number of sacral vertebrae, with "Apatosaurus" possessing three and "Atlantosaurus" four. Two years later, Marsh announced the discovery of a larger and more complete specimen at Como Bluff, Wyoming. He gave this specimen a new name based on the conventions of his age and the relatively sparse fossil record available at that time. It was later recognised that the features he had used to distinguish