Editing Protoceratops (section)

===Digging behavior===
[[File:Protoceratops andrewsi right leg.jpg|thumb|Fossil cast of ''P. andrewsi'' showing left hindlimb, equipped with large, flat, shovel-like unguals]]
Longrich in 2010 proposed that ''Protoceratops'' may have used its hindlimbs to [[Fossorial|dig burrows]] or take shelter under [[bushes]] and/or scrapes to escape the hottest temperatures of the [[Daytime|day]]. A digging action with the hindlimbs was likely facilitated by the strong [[caudofemoralis]] muscle and its large feet equipped with flat, shovel-like unguals. As this behavior would have been common in ''Protoceratops'', it predisposed individuals to become entombed alive during the sudden collapse of their [[burrow]]s and high energy sand-bearing events—such as [[sandstorm]]s—and thus explaining the standing ''[[in-situ]]'' posture of some specimens. Additionally, Longrich suggested that a backward burrowing could explain the preservation of some specimens pointing forward with curved tails.<ref name=Longriich20110/>

In 2019, Victoria M. Arbour and David C. Evans cited the robusticity of the ulna of ''[[Ferrisaurus]]'' as a useful feature for digging, which may have been also true for ''Protoceratops''.<ref>{{cite journal|last1=Arbour|first1=V. M.|last2=Evans|first2=D. C.|date=2019|title=A new leptoceratopsid dinosaur from Maastrichtian-aged deposits of the Sustut Basin, northern British Columbia, Canada|journal=PeerJ|volume=7|pages=e7926|doi=10.7717/peerj.7926|doi-access=free|pmc=6842559|pmid=31720103}}</ref>