Habits of the Pacific Walrus (Odobenus divergens)

Collins, G. N.

doi:10.2307/1374970

Cited by 11 publications

(8 citation statements)

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“…By analogy, the length of the embryonic Pacific walrus at implantation would be about 3 or 4 cm, and the time of implantation would be in late June to late July. My findings and those reported by Belopol'skii (1939), Collins (1940), Brooks (1954), Krylov (1966bKrylov ( , 1969, and J. J. Burns (unpublished data), lend support to that prediction (Table 32).…”

Section: Time Of Implantationsupporting

confidence: 79%

“…Krylov (1969) reported the finding of implanted embryos 7 and 9 cm long in two females taken on 13 June. Belopol'skii (1939) and Collins (1940) found implanted embryos and fetuses in several females during July but did not indicate whether they examined other females without finding any embryos. Krylov (1969) reported six implanted embryos 13 to 25 cm long (nose-tail length) from females taken on 2 and 20 July; earlier (Krylov 1966b), he reported another female in July with an unimplanted blastocyst.…”

Section: Time Of Implantationmentioning

confidence: 96%

“…My sources of published records were Chechulin (1936), Belopol'skii (1939), Collins (1940), Freiman (1941), Nikulin (1941Nikulin ( , 1947, Wilke (1942), Porsild (1945), Lantis (1946), Rainey (1947), Brooks (1953Brooks ( , 1954, Fay (1957), Manville (1961), Fedoseev (1962Fedoseev ( , 1966, Yablokov and Bel'kovich (1963), Burns (1965), Anonymous (1965), Harington (1966), Johnson et al (1966), Krylov (1966aKrylov ( , 1968, Gol'tsev (1968), Kosygin and Sobolevskii (1971), Watson and Divoky (1972), Stirling (1974), Tomilin and Kibal'chich (1975), Pinigin and Prianish- nikov (1975), Heptner et al (1976), and Estes and Gilbert (1978). Most of the unpublished data are from aerial surveys conducted by H. W. Braham, J. J.…”

Section: Distribution and Migrationsmentioning

confidence: 99%

“…Several investigators have estimated that the mating of walruses occurs in the spring, at various times from mid-April to July (Chapskii 1936;Collins 1940;Brooks 1954;Mansfield 1958a;Krylov 1962). Those estimates were based mainly on comparative embryonic development, rather than actual evidence of ovulation, and were made with the assumption that in the walrus there is no delayed implantation.…”

Section: Time Of Matingmentioning

confidence: 99%

“…Apparently, most of the Soviet harvest by natives is taken during the summer months. From the early 1900's to the mid-1950's, the Alaskan retrieved harvest is believed to have ranged from about 1,000 to 1,500 walruses per year (Collins 1940;Brooks 1954;Fay 1957 and unpublished data). These estimates were based on rather fragmentary information, for there was no regular monitoring of the harvests during that time.…”

Section: Harvests By Manmentioning

confidence: 99%

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Ecology and Biology of the Pacific Walrus,Odobenus rosmarus divergensIlliger

Fay¹

1982

North American Fauna

394

567

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Section: Time Of Implantationsupporting

confidence: 79%

Section: Time Of Implantationmentioning

confidence: 96%

Section: Distribution and Migrationsmentioning

confidence: 99%

Section: Time Of Matingmentioning

confidence: 99%

Section: Harvests By Manmentioning

confidence: 99%

See 3 more Smart Citations

Ecology and Biology of the Pacific Walrus,Odobenus rosmarus divergensIlliger

Fay¹

1982

North American Fauna

394

567

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Resource partitioning between Pacific walruses and bearded seals in the Alaska Arctic and sub-Arctic

et al. 2017

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Climate-mediated changes in the phenology of Arctic sea ice and primary production may alter benthic food webs that sustain populations of Pacific walruses (Odobenus rosmarus divergens) and bearded seals (Erignathus barbatus). Interspecific resource competition could place an additional strain on ice-associated marine mammals already facing loss of sea ice habitat. Using fatty acid (FA) profiles, FA trophic markers, and FA stable carbon isotope analyses, we found that walruses and bearded seals partitioned food resources in 2009-2011. Interspecific differences in FA profiles were largely driven by variation in non-methylene FAs, which are markers of benthic invertebrate prey taxa, indicating varying consumption of specific benthic prey. We used Bayesian multi-source FA stable isotope mixing models to estimate the proportional contributions of particulate organic matter (POM) from sympagic (ice algal), pelagic, and benthic sources to these apex predators. Proportional contributions of FAs to walruses and bearded seals from benthic POM sources were high [44 (17-67)% and 62 (38-83)%, respectively] relative to other sources of POM. Walruses also obtained considerable contributions of FAs from pelagic POM sources [51 (32-73)%]. Comparison of δC values of algal FAs from walruses and bearded seals to those from benthic prey from different feeding groups from the Chukchi and Bering seas revealed that different trophic pathways sustained walruses and bearded seals. Our findings suggest that (1) resource partitioning may mitigate interspecific competition, and (2) climate change impacts on Arctic food webs may elicit species-specific responses in these high trophic level consumers.

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