Does the evolutionarily stable strategy apply to captive Humboldt penguins? Study on S. humboldti lateralized behavior

Abstract

So far, little has been done on the motor and perceptual asymmetry in the genus Spheniscus, which on the contrary, has been the target of much research in the wild due to its vulnerable ecological condition. The present study aimed to investigate the presence of lateralization on different asymmetry dimensions in Humboldt penguins by studying fourteen subjects housed in a captive colony in Italy. For each individual, the preferred foot to start walking and climbing on a weighing scale, the preferred side to reach the uropygium, and the preferred eye to scrutinize visitors outside the exhibit were recorded. Asymmetry was found at the individual level for the preferred foot to climb onto the scale (three left and five right out of 14) and the preferred side to reach the preen gland (two left and five right out of 14). Only thirteen penguins were seen interacting with people outside the exhibit using their left (four) or right (three) eye while swimming in the pool. No lateralization could be documented at the population level. The lack of lateralization at the population level could be attributable to the small size of the colony studied, hampering speculations on the social life of S. humboldti. Since the requirement for coordinated behaviors at the population level occurs when social interactions become common and recurrent in the natural behavior of a species, and because only one among the items studied was devoted to the study of social behavior, it will be necessary to broaden the research to other captive S. humboldti populations to expand our results. Data obtained from a larger number of animals could unveil a little piece of the puzzle that will allow evaluating lateralization at the population level in this species and ascertain if the Evolutionarily Stable Strategy could also be applied to S. humboldti.