Raven Spencer

Document Type

Internship Report

Publication Date

Fall 2017


Lateralization in foraging, swim patterns and mother-offspring pairs have been predominantly documented in cetaceans with researchers beginning to study terrestrial species; however maternal lateralized behavior in pinnipeds has not been extensively studied (Clapham et al. 1995, Karenina et al. 2017, Wells 2003, Wells et al. 2006). The purpose of this project was to assess lateralization among the endangered western distinct population segment of Steller sea lion (Eumetopias jubatus) mother-pup dyads using video footage collected at Chiswell Island in Alaska. Positional data were collected from 23 mother-pup dyads on the rookery at Chiswell Island. Photographs were taken during scan samples to acquire an accurate depiction of the side biases exhibited during the breeding season from June – July 2017. Overall pups were left-lateralized, using their left eye to focus on their mothers, which could promote social bonding (Karenina et al. 2013a, Salva et al. 2012). Females were right-lateralized for “other” behaviors excluding resting behavior and maternal attentiveness. In addition, as the season progressed, both females and pups switched their positional biases, which may suggest this strategy is a form of protection as more Steller sea lions arrived on the rookery. These findings corresponded with other studies suggesting offspring have a left-eye preference (Hill et al. 2017). The results suggested that Steller sea lions on Chiswell were slightly lateralized and this lateralized behavior may improve maternal care and provide insight into the behaviors of an endangered population.


Department: MES

MPS Track: MCO

Location: Pam Parker and John Maniscalco Alaska SeaLife Center

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