Gynomimicry in the Dwarf Gwembe breed from Zambia

Abstract

Sexual size dimorphism is a widespread phenomenon in different animal taxa, including the subfamily of goats and sheep. The purpose of this research was to study the sexual dimorphism of males and females of Gwembe Dwarf Goat based solely on cephalic indexes. Eleven indices were calculated for 30 dry skulls of adult Gwembe Dwarf Goat specimens aged 18 months and older. Sexes appeared no significatively different. This form of heterosexual mimicry must be viewed as simply as strongly human-selected for. The importance of controlled competition is capable of countering antagonist to peer competition, so no sexual competition appears. When the artificial nature of sexual competition is taken into account, Darwin's theory of sexual selection becomes not applicable to domestic goats -or at least to the Dwarf Gwembe breed-, which fail to develop the expected degree of sexual dimorphism. The breed can then described as a monomorphic and, more concretely, gynomimic - imitation of female secondary sexual characters by males-.