The ethologist examines this question primarily from the point of view of ontogenetic development. Further complicating matters are the diverse interpretations of ontogenetic and sexual features in pachycephalosaurs. It was reported that all ontogenetic stages were present. A second skeleton, also from a juvenile of a similar ontogenetic stage, is also known. There are two types of dichromatism for frog species&colon; ontogenetic and dynamic. These comparisons are complex because there are no universal ontogenetic timemarkers. However, it is considered to be an intraspecific, possibly ontogenetic, variation. There is also interspecies variation, especially ontogenetic changes as a fish experiences growth. There has been substantial ontogenetic and individual variability found in the morphology of this feature. More than 16 well-preserved specimen of various ontogenetic stages were referred to this species. At this ontogenetic stage, cane toads contain the lowest concentration of toxins. There appear to be nine cranial features that successfully separate "Thrinaxodon" into four ontogenetic stages. Another plausible ontogenetic change is the increased pneumatization of the vertebrae. During their ontogenetic development, in juveniles at first the ribs fused with their vertebrae. This species, in its various forms, shows considerable ontogenetic variation.