Toy rabbits are selected for their paedomorphic ('babyish') appearance. The main objective of this study is to analyse the skull asymmetries of toy rabbits. For this purpose, a total of 46 adult skulls (9 males and 37 females) were studied. Geometric morphometric technique with five pairs of anatomical landmarks and three on sagittal plane on dorsal aspect of skull was used. Our hypothesis is that through artificial selection on males (which are the main subject for obtaining new phenotypes among toys) asymmetries will be expressed as higher asymmetrical values. Skulls’ size was similar between sexes, but males presented a higher level of fluctuating asymmetry. Fluctuating asymmetry indicates a negative ability to buffer subtle developmental anomalies, normally from genetic or environmental origin. In other words, males would be under stronger directed selection and consequently be more affected by management (including selective) factors compared to females. These results can allow a better understanding of the patterns and processes underlying sexual shape dimorphism, especially with extreme phenotypes, as toy rabbits are.

KEY WORDS: Bilateral asymmetry; Oryctolagus cuniculus; Osteology; Paedomorphy; Sexual dimorphism.