Behavioral assessment of in-air hearing range for the Pacific walrus (Odobenus rosmarus divergens)

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.

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ANTIBODIES TO MARINE CALICIVIRUSES IN THE PACIFIC WALRUS (ODOBENUS ROSMARUS DIVERGENS ILLIGER)

Journal of Wildlife Diseases ◽

10.7589/0090-3558-22.2.165 ◽

1986 ◽

Vol 22 (2) ◽

pp. 165-168 ◽

Cited By ~ 6

Author(s):

J. E. Barlough ◽

E. S. Berry ◽

D. E. Skilling ◽

A. W. Smith ◽

F. H. Fay

Keyword(s):

Pacific Walrus ◽

Odobenus Rosmarus Divergens ◽

Odobenus Rosmarus ◽

The Pacific

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Fay, F. H. ECOLOGY AND BIOLOGY OF THE PACIFIC WALRUS, ODOBENUS ROSMARUS DIVERGENS ILLIGER. U.S. Dept. Interior, North American Fauna, 74:v + 1-279, illustrated, 1982

Journal of Mammalogy ◽

10.2307/1381268 ◽

1985 ◽

Vol 66 (2) ◽

pp. 421-422 ◽

Cited By ~ 1

Author(s):

E. H. Miller

Keyword(s):

North American ◽

Pacific Walrus ◽

Odobenus Rosmarus Divergens ◽

Odobenus Rosmarus ◽

The Pacific

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Female Pacific walruses (Odobenus rosmarus divergens) show greater partitioning of sea ice organic carbon than males: Evidence from ice algae trophic markers

PLoS ONE ◽

10.1371/journal.pone.0255686 ◽

2021 ◽

Vol 16 (8) ◽

pp. e0255686

Author(s):

Chelsea W. Koch ◽

Lee W. Cooper ◽

Ryan J. Woodland ◽

Jacqueline M. Grebmeier ◽

Karen E. Frey ◽

...

Keyword(s):

Organic Carbon ◽

Sea Ice ◽

Nitrogen Isotopes ◽

Chukchi Sea ◽

Trophic Position ◽

Ice Algae ◽

Pacific Walrus ◽

Odobenus Rosmarus Divergens ◽

Odobenus Rosmarus ◽

The Pacific

The expected reduction of ice algae with declining sea ice may prove to be detrimental to the Pacific Arctic ecosystem. Benthic organisms that rely on sea ice organic carbon (iPOC) sustain benthic predators such as the Pacific walrus (Odobenus rosmarus divergens). The ability to track the trophic transfer of iPOC is critical to understanding its value in the food web, but prior methods have lacked the required source specificity. We analyzed the H-Print index, based on biomarkers of ice algae versus phytoplankton contributions to organic carbon in marine predators, in Pacific walrus livers collected in 2012, 2014 and 2016 from the Northern Bering Sea (NBS) and Chukchi Sea. We paired these measurements with stable nitrogen isotopes (δ15N) to estimate trophic position. We observed differences in the contribution of iPOC in Pacific walrus diet between regions, sexes, and age classes. Specifically, the contribution of iPOC to the diet of Pacific walruses was higher in the Chukchi Sea (52%) compared to the NBS (30%). This regional difference is consistent with longer annual sea ice persistence in the Chukchi Sea. Within the NBS, the contribution of iPOC to walrus spring diet was higher in females (~45%) compared to males (~30%) for each year (p < 0.001), likely due to specific foraging behavior of females to support energetic demands associated with pregnancy and lactation. Within the Chukchi Sea, the iPOC contribution was similar between males and females, yet higher in juveniles than in adults. Despite differences in the origin of organic carbon fueling the system (sea ice versus pelagic derived carbon), the trophic position of adult female Pacific walruses was similar between the NBS and Chukchi Sea (3.2 and 3.5, respectively), supporting similar diets (i.e. clams). Given the higher quality of organic carbon from ice algae, the retreat of seasonal sea ice in recent decades may create an additional vulnerability for female and juvenile Pacific walruses and should be considered in management of the species.

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Observations of Annual Walrus (Odobenus rosmarus divergens) Migrations in the Nearshore Waters of the Chukotka Peninsula from 1990 to 2012

ARCTIC ◽

10.14430/arctic70035 ◽

2020 ◽

Vol 73 (1) ◽

pp. 99-113

Author(s):

Vladimir V. Melnikov

Keyword(s):

Marine Mammals ◽

Chukchi Sea ◽

Relative Number ◽

Bering Strait ◽

Pacific Walrus ◽

Odobenus Rosmarus Divergens ◽

Odobenus Rosmarus ◽

Commercial Harvest ◽

The Pacific ◽

Pass Through

After the end of the commercial harvest, research regarding the Pacific walrus (Odobenus rosmarus divergens) in Russia was reduced and focused on the observation of animals at land-based haul-outs. This paper presents the long-term observations of the distribution, relative abundance, and direction of seasonal movements of walruses in the offshore waters of the Chukotka Peninsula, based on data obtained in 1990 – 2012. Observations of Pacific walruses and other marine mammals were conducted mainly from April through November, but some were conducted all year round. In some years up to 30 Native Chukotkan observers were employed at this task. Some watched from observation posts in Native villages onshore, and others from motorboats during hunting trips. These observations have shown that walruses are rare in January and February in the nearshore waters of the Chukotka Peninsula. Their numbers begin to increase in March. The northward movement of walruses begins in April, and walruses migrate from the Bering Sea to the Chukchi Sea throughout the summer months and early autumn. Based on observations from posts located directly in front of the southern Bering Strait, I conclude that 106 – 1055 walruses pass through the Bering Strait from July to September, to the northwest and north. At the haul-outs in the Gulf of Anadyr, the relative number of walruses remains stable during the summer (up to 11 000 individuals at all haul-outs in total based on observers’ estimates) and decreases only with the appearance of ice in October – November.

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