However, recent work has shown that Nemegtosaurus is in fact a titanosaur, closely related to animals such as Saltasaurus,[1] Alamosaurus and Rapetosaurus.

A second species, N. pachi, was described by Dong in 1977 on the basis of the teeth IVPP V.4879, recovered from the Subashi Formation, but is a nomen dubium.

Comparisons between the scleral rings of Nemegtosaurus and modern birds and reptiles suggest that it may have been cathemeral, active throughout the day at short intervals.

There, on a lush river delta flowing through the ancient sands of the Gobi Desert, Nemegtosaurus would have coexisted with animals like the ornithomimid Gallimimus, the alvarezsaurid Mononykus, the velociraptorine Adasaurus, and the giant, saber-clawed therizinosaur Therizinosaurus.

With its possible body length of 12 metres (39 ft),[6] an adult Nemegtosaurus may have been able to defend against Tarbosaurus, but juveniles would have been vulnerable.