Brontosaurus
"Brontosaurus" was a large, long-necked quadrupedal animal with a long, whip-like tail, and forelimbs that were slightly shorter than its hindlimbs. The largest species, "B. excelsus", weighed up to and measured up to long from head to tail. For comparison, the current largest land animal, the average male African bush elephant is 3.20 m (10.5 ft) tall at the shoulder and has a body mass of 6,000 kg (13,228 lb) or 6.6 short tons.
Bruhathkayosaurus
No total body size estimates for "Bruhathkayosaurus" have been published, but paleontologists and researchers have posted tentative estimates on the Internet. In a blog post from June 2001, Mickey Mortimer estimated that "Bruhathkayosaurus" could have reached in length and might have weighed 175–220 tons, but in later blog posts retracted these estimates, reducing the estimated length of "Bruhathkayosaurus" to , and declined to provide a new weight estimate, describing the older weight estimates as inaccurate. In a May 2008 article for the weblog "Sauropod Vertebra Picture of the Week", paleontologist Matt Wedel used a comparison with "Argentinosaurus" and calculated the weight of "Bruhathkayosaurus" at up to 126 metric tons.