Lateralisation of conspecific vocalisation in non-human vertebrates.

Lateralisation of conspecific vocalisation has been observed in several vertebrate species. In the present article we review the results of behavioural and neuroanatomical studies investigating this feature. By employing cladographic comparisons we identify those vertebrate orders in which evidence for or against lateralisation of production and perception of conspecific vocalisation has been reported, and those orders in which further research is necessary. The analysis shows that there is evidence for lateralisation of conspecific vocalisation in several mammalian orders (e.g., Primates) and also evidence for lateralisation of conspecific vocalisation in some avian species (e.g., within the Passeriformes order). While the primate data in particular suggest that human language lateralisation could have resulted from an inherited dominance of the left hemisphere for those neural properties of language that are shared with the sensory or motor aspects of vocalisations in other vertebrate species, it becomes clear that this conclusion is presently supported by only sparse empirical evidence. The majority of vertebrate orders, especially among non-amniotes, still need to be explored.