Motor and postural asymmetries in marsupials: Forelimb preferences in the red-necked wallaby (Macropus rufogriseus)

In the last decades, several studies on mammal motor lateralization have been carried out. However, data on marsupials are still underrepresented in the literature, despite their importance in tracing the evolution of motor laterality and its functional value. This study aimed at investigating motor lateralization in a sample of captive red-necked wallabies (Macropus rufogriseus), considering different daily unimanual activities and forelimb implication in postural support. Data on forelimb preference for food reaching, pulling food out of the mouth, self-scratching and starting locomotion from quadrupedal posture were collected; furthermore, to investigate the role of posture in determining the forelimb laterality of wallabies, data on forelimb use for postural support in tripedal stance were recorded. Our results revealed significant group-level left forelimb preferences for self-scratching and starting locomotion, as well as for providing postural support in tripedal stance. These results are discussed in the light of theories for a right hemisphere dominance for emotion processing and for postural influences on forelimb dominance throughout evolution. The reported left biases in forelimb use for different behaviours are in agreement with previous literature on macropods.