Visual lateralization in artiodactyls: A brief summary of research and new evidence on saiga antelope

ABSTRACT

The visual system and lifestyle characteristics make the even-toed ungulates an excellent model for the studies of behavioural lateralization. Recent research has focused on these mammals providing evidence of lateralization in a wide range of behaviours. This provides an opportunity for the collation of the current theoretical assumptions and the existing empirical evidence for visual lateralization in artiodactyls. In the present study, we aim first to gain a fuller picture of hemispheric specializations in saiga antelopes by investigating the lateralization of vigilance and novel object inspection in the wild. Second, we summarized the results of the research into visual lateralization in even-toed ungulates and attempted to assess the applicability of two popular hypotheses about the division of hemispheric roles. The results on saigas show a significant preference for head turns to the right visual field during vigilance which was more robust in individuals in larger groups. When an unfamiliar artificial object was placed in their natural setting, saigas preferentially viewed it predominantly with the right eye. These results, together with the cumulative evidence in artiodactyls, do not follow either the approach—withdrawal or positivity—negativity dichotomous patterns widely used to explain the division of functions between the hemispheres.

KEYWORDS:

• Laterality
• eye preference
• vigilance
• novelty
• brain specialization

Acknowledgements

We are deeply grateful to Yegor Malashichev for the inspiration for this study. We would like to thank Anna Lushchekina and the staff of Stepnoi State Nature Sanctuary, and especially Vladimir Kalmykov and Galina Kalmykova, for their valuable organizational support and assistance during data collection.

Authors’ contributions

B.F. designed the study devoted to lateralization of vigilance, collected the data, and co-wrote the manuscript. E.B. collected and analyzed the data on the inspection of a novel object. A.G. contributed to the general study design, analyzed the data, and edited the manuscript. K.K. coordinated the study, analyzed the data, and wrote the manuscript. All authors read and approved the final manuscript.

Data availability

The data supporting the findings of this study are available within the article and its supplementary information files.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Russian Science Foundation under Grant (no. 19-14-00119).