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 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