Mating Behaviors Exhibited by a Captive Male Pacific Walrus (Odobenus rosmarus divergens)

Jessica M Mccord,Dianne Cameron,Erin E Frick,Stan A Kuczaj Ii

doi:10.46867/ijcp.2016.29.00.18

Abstract

The population of the Pacific walrus (Odobenus rosmarus divergens) is currently a topic of conservation efforts. Understanding the mating behaviors of a species can be utilized in conservation efforts to preserve the species. Little is known about the behavioral repertoire of Pacific walruses, due to their isolated Arctic habitats, with limited studies previously describing observations of walrus mating behaviors. The aim of the present case study was to observe the mating behaviors of a single captive male Pacific walrus to examine overall frequency of specific mating behaviors in both social and solitary contexts. The subjects, one male and two females, were recorded at Six Flags Discovery Kingdom from November 2013 through January 2014. Only behaviors exhibited by the male walrus directly associated with mating were noted. Grabs were the most frequently observed behavior, and holds were not significantly observed which could contribute to the infrequent successful copulation attempts. Pharyngeal sac inflation, a vocal and visual behavior, was not frequently observed in a sexual context but has been observed in mating contexts in the wild. The male walrus used other sexual outlets such as self-gratification and toy use; however, these behaviors occurred significantly less than sexual encounters with females. There appeared to be a mate preference for the female with tusks, as the male interacted significantly more with the tusked female compared to the non-tusked female who was in estrus. Studying mating behavior in controlled settings such as this can be revealing of the capabilities of the species as a whole. Understanding more about how walruses interact in their environment can be used for future management and breeding strategies.

Highlights

The population of the Pacific walrus (Odobenus rosmarus divergens) is currently a topic of conservation efforts
Jay and colleagues (2011) utilized a Bayesian network model to integrate how the changing environmental and anthropogenic factors will affect Pacific walrus population trends throughout the remainder of the century. Their results indicated a steady trend of worsening walrus outcome probabilities, increasing from a current 10% probability to approximately 40% by 2095. While this estimated model determines the environmental stressors that largely contribute to this projected trend, the authors conclude that the influence of other stressors is not well-understood due to how little we currently know about the walrus behavioral repertoire, such as their reproductive behaviors
The male was more likely to engage in mating behaviors with the females than exhibit self-gratification; toy use was not found to be significant as a sexual outlet

Summary

Introduction

The population of the Pacific walrus (Odobenus rosmarus divergens) is currently a topic of conservation efforts. There is increased concern for conservation efforts for the Pacific walrus, as the species is hypothesized to suffer population loss through the end of the century due to the continued and increased loss of sea ice in the Arctic Ocean (Jay, Marcot, & Douglas, 2011). Jay and colleagues (2011) utilized a Bayesian network model to integrate how the changing environmental and anthropogenic factors will affect Pacific walrus population trends throughout the remainder of the century. Their results indicated a steady trend of worsening walrus outcome probabilities, increasing from a current 10% probability to approximately 40% by 2095. Examining factors that contribute to breeding in walruses, such as genetics and behavioral functions, may assist with sustaining populations (Lacy, 2013)

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