The armor and spikes of "Desmatosuchus" were its only ways to defend itself from predators. The lateral spike rows showed variation in size among individuals, especially the second most anterior spike. This spike was always shorter than the one in front of it, but to what extent varied drastically. This variation may indicate sexual dimorphism. It has also been hypothesized as a form of sexual display. Aside from this armor, "Desmatosuchus" was defenseless from attacks from carnivores. Several "Desmatosuchus" bones have been found amongst skeletons of "Postosuchus", indicating predation by "Postosuchus". The herd nature of "Desmatosuchus" apparently did little to discourage predators, as "Postosuchus" along with several other Late Triassic carnivores also traveled in groups.