"Erlikosaurus" lived alongside a larger species of therizinosaurid in the Bayan Shireh Formation, "Segnosaurus". In 2016, Zanno and colleagues re-examined the lower jaws and dentition of "Segnosaurus" making direct comparisons with those of "Erlikosaurus" in the process. They identified rather complex features in the dentary teeth of "Segnosaurus", which are represented by the presence of numerous carinae (cutting edges) and folded carinae with denticulated front edges, and the enlargement of denticles (serrations). These traits together create a roughened, shredding surface near the base of the tooth crowns that was unique to "Segnosaurus" and suggest it consumed unique food resources or used highly specialized feeding strategies, with the addition of a higher degree of oral food processing than the sympatric—related species that lived in the same area at the same time—"Erlikosaurus". On the contrary, the latter has very symmetrical teeth with moderate denticles. The respective indistinct and specialized dentition of "Erlikosaurus" and "Segnosaurus" indicates that these two therizinosaurids were separated by niche differentiation in food acquisition, processing, or resources. This conclusion is strengthened by the large difference in estimated body masses, which is up to 500%.