Preferential use of one paw during feeding in the subterranean rodent Ctenomys talarum

Abstract

Initially believed to be a uniquely human characteristic, the preference to use one extremity for carrying out diverse activities, such as feeding or self-grooming, has been observed in several groups of vertebrates and even in some invertebrates (1,2,3). These behavioral asymmetries, which may reflect differences in the roles of the two brain hemispheres, are classified according to their occurrence in the individuals at the population level: no asymmetry, when all individuals prefer to use both the left and the right limb with equal probability; individuallevel asymmetry, when some individuals of the population prefer to use one extremity while others prefer to use the other limb (no asymmetry at the population level); and population asymmetry, when most of the individuals prefer to use either the left or the right limb (3).