[1] Due to a lack of other herbivores, the genus underwent an adaptive radiation, filling niches occupied by other taxa on the mainland.

De Vos (1979, 1984, 1996)[5][6][7] identified eight morphotypes into one genus (Candiacervus), whereas Capasso Barbato (1992)[8] included the larger species, rethymnensis, major and dorothensis, in Cervus (subgenus Leptocervus) and the smaller species ropalophorus and cretensis in Megaloceros (subgenus Candiacervus), implying two different ancestors, and she also did not recognize sp.

A new paper published in 2018 rejected the conclusion of Capasso Barbato (1992) and formally named the three morphotypes of De Vos' Candiacervus sp.

[11] The Cretan deer is represented by no less than eight different morphotypes, ranging from dwarf size with withers height of about 40 centimetres (16 in) to very large with withers height of about 165 centimetres (65 in),[6] spanning a body mass range from 27.8 kilograms (61 lb) in the smallest species C. ropalophorus to 245.4 kilograms (541 lb) in the largest species C. major.

[12] The short legs of the dwarf species is suggested to be an adaptation to a goat-like niche of climbing around on rocky terrain and consuming low quality foliage.

[17] Despite living in an environment free of large terrestrial predators, the species of Candiacervus exhibited relatively high rates of juvenile mortality, with likely causes of death being accidents and malnutrition.

Another option is a gradual depletion of the ecosystem, as indicated by the finding of a complete herd consisting of individuals suffering a bone disease of an osteosclerotic nature.