Under the hypothesis that it was among the first amniotes in the biological sense, it would have laid an amniotic egg not dependent on being laid in water to survive, possibly hiding them in damp vegetation or hollowed out tree stumps. This has been inferred from the fact that "Casineria" was found in rocks showing a rather dry environment. In the early Carboniferous period before the appearance of "Casineria", vertebrates were primarily aquatic, only spending part of their time on land. "Casineria" was believed to be among the first vertebrates to live and reproduce on land.