Percent of lateralized individuals in marsupials with different species-typical body orientation. The figure contains data on grey short-tailed opossums (Monodelphis domestica), N = 26, sugar gliders (Petaurus breviceps), N = 23, and red-necked wallabies (Macropus rufogriseus), N = 27. Each bar represents the percent of subjects, which showed significant forelimb preferences based on individual z scores (for feeding on non-living food in grey short-tailed opossums and sugar gliders (Table 1, 2) and for feeding on grass/hay from the bipedal position in red-necked wallabies ). The percentage of lateralized individuals increases in the row of marsupial species from terrestrial quadruped (grey short-tailed opossum) and arboreal quadruped (sugar glider) to biped (red-necked wallaby), i.e. together with enhancement of body verticality.
Giljov et al. BMC Evolutionary Biology 2013 13:61 doi:10.1186/1471-2148-13-61