Some of the skinks traditionally placed in "Egernia" appear to be among the most intelligent squamates. They have been shown to be able to distinguish between relatives and unrelated conspecifics, and can recognize relatives individually. Several species form monogamous pair-bonds. Most of these species belong to "Egernia sensu stricto", and similar behaviour is also known in the related Solomon Islands skink ("Corucia zebrata"). The latter means that the high intelligence and social skills are probably plesiomorphic for the "Egernia" genus-group as a whole, and that the solitary species appear to have evolved towards being less intelligent and social again. It may still be, however, that the intelligent behaviour is a homoplasy that evolved several times in the "Egernia" genus-group; the fact that "Corucia" is a monotypic and rather distinct genus makes it impossible to decide at present.