Editing Protoceratops (section)

===Social behavior===
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|image1=Protoceratops specimen block MPC-D 100 526.png

|caption1=''P. andrewsi'' specimen MPC-D 100/526

|image2=Protoceratops specimen MPC-D 100 534.png

|caption2=''P. andrewsi'' specimen MPC-D 100/534
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Tomasz Jerzykiewiczz in 1993 reported several [[monospecific]] (containing only one dominant species) death assemblages of ''Protoceratops'' from the Bayan Mandahu and Djadokhta formations. A group of five medium-sized and adult ''Protoceratops'' was observed at the Bayan Mandahu locality. Individuals within this assemblage were lying on their bellies with their heads facing upwards, side by side parallel-aligned, and inclined about 21 [[Degree symbol|degrees]] from the horizontal plane. Two other groups were found at the Tugriken Shireh locality; one group containing six individuals and another group of about 12 skeletons.<ref name=Jerzykiewiczz1993/>

In 2014, David W. E. Hone and colleagues reported and described two blocks containing death assemblages of ''P. andrewsi'' from Tugriken Shireh. The first block (MPC-D 100/526) comprises four juvenile individuals in close proximity with their heads pointing upwards, and the second block (MPC-D 100/534) is composed of two sub-adults with a horizontal orientation. Based on previous assemblages and the two blocks, the team determined that ''Protoceratops'' was a [[Social behavior|social dinosaur]] that formed [[herd]]s throughout its life and such herds would have varied in composition, with some including adults, sub-adults, siblings from a single nest or local members of a herd joining shortly after hatching. However, as the group could have loss members by [[predation]] or other factors, the remnants individuals would [[Sociality|aggregate]] into larger groups to increase their survival. Hone and colleagues in particular suggested that juveniles would aggregate primarily as a [[Anti-predator adaptation|defense against predators]] and an increased protection from the multiple adults within the group. The team also indicated that, while ''Protoceratops'' provides direct evidence for the formation of single cohort aggregations throughout its lifespan, it cannot be ruled out the possibility that some ''Protoceratops'' were solitary.<ref name=Hone2014>{{cite journal|last1=Hone|first1=D. W. E.|last2=Farke|first2=A. A.|last3=Watabe|first3=M.|last4=Shigeru|first4=S.|last5=Tsogtbaatar|first5=K.|date=2014|title=A New Mass Mortality of Juvenile Protoceratops and Size-Segregated Aggregation Behaviour in Juvenile Non-Avian Dinosaurs|journal=PLOS ONE|volume=9|issue=11|pages=e113306|doi=10.1371/journal.pone.0113306|doi-access=free|pmc=4245121|pmid=25426957|bibcode=2014PLoSO...9k3306H }}</ref>