Ethology and Behavioral Ecology of the Walrus (Odobenus rosmarus), with Emphasis on Communication and Social Behavior

Miller, Edward H.; Kochnev, Anatoly

doi:10.1007/978-3-030-59184-7_22

Cited by 6 publications

(5 citation statements)

References 160 publications

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“…All walruses exhibited typical surface behaviors such as back-up postures by diving head first that are related to typical foraging dives (Born and Knutsen 1997; Garde et al 2018). During foraging behavior, walruses continuously dive at the same spot (Miller and Kochnev 2021). Hence after sound recordings, when walruses left the feeding area (up to ca.…”

Section: Data Collectionmentioning

confidence: 99%

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Passive acoustics suggest two different feeding mechanisms in the Atlantic walrus (Odobenus rosmarus rosmarus)

et al. 2022

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The vocal repertoire of walruses has been widely described in the bioacoustic literature. These marine mammals produce several distinct types of vocalizations for intraspecific communication during the breeding season. In this study, we provide the first evidence of walrus-generated sounds during foraging dives when they feed on bivalves. We recorded two types of sounds that we associated to different feeding mechanisms. The first sound type was brief and low in frequency that we relate to the suction of soft parts from the bivalves' shells through the use of walrus powerful tongues, which is the common feeding behavior reported in the walrus literature. We also recorded a second sound type composed of multiple broadband pulse trains. We hypothesize the latter were associated with bivalve shell cracking by walruses, which would represent a new feeding mechanism in the walrus literature. This new feeding mechanism is either related to bivalves' ecology or to walruses removing the sediment when searching for food. During this study, we observed bivalves lying on the seafloor instead of being buried in the sediment in walrus feeding areas while scuba diving. As a result, walruses cannot use suction to feed on Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site.soft body part of bivalves and have to use another strategy, mastication. Our findings provide a first step towards using passive acoustics to quantify walrus behavior and feeding ecology.

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Section: Data Collectionmentioning

confidence: 99%

“…Stirling et al 1983;Miller 1985;Mouy et al 2012;Charrier 2021). In contrast, bell calls are long and made of a single frequency(Schevill et al 1966;Stirling et al 1987;Sjare et al 2003;Miller and Kochnev 2021). These two types of calls were recorded at the same time during walrus dives (Figure1).…”

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confidence: 95%

Passive acoustics suggest two different feeding mechanisms in the Atlantic walrus (Odobenus rosmarus rosmarus)

et al. 2022

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“…On its surface, the term "distress call" is a poor label for a behavioural category: it is interpretive rather than descriptive, and implies functions that reflect an observer's view; it includes a word ("distress") that in itself has no widely accepted definition; the category, its acoustic properties, and its control mechanisms surely are not homologous across species; mechanisms and functions of the calls obviously must vary greatly across age, sex, social class, stage of the annual cycle; and so on (Marler, 2004). Nevertheless, if such terms are described and defined clearly enough to be interpretable and independently repeatable in other studies, we feel that their use is defensible (Miller & Kochnev, 2021). Our labeling of calls of hand-held plover chicks as "distress calls" falls in this category.…”

Section: Introductionmentioning

confidence: 99%

Anatomy of avian distress calls: structure, variation, and complexity in two species of shorebird (Aves: Charadrii)

Miller

Kostoglou

Wilson

et al. 2022

Behav.

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Birds often vocalize when threatened or captured by a predator. We present detailed qualitative analyses of calls from 24 red-capped plover (Charadrius ruficapillus) and 117 masked lapwing (Vanellus miles) chicks (Charadriidae) that we recorded during handling. Calls were structurally complex and differed between species. Calls showed moderate structure at higher levels of organization (e.g., similarity between successive calls; sequential grading). Some call characteristics resembled those in other bird species in similar circumstances (e.g., in nonlinear phenomena). Most calls consisted of several different parts, which combined in different ways across calls. Past studies have overlooked most features of distress calls and calling in charadriids due to small sample sizes and limited spectrographic analyses. Understanding interspecific patterns in call structure, and determination of call functions, will require: detailed knowledge of natural history; detailed behavioural descriptions, acoustic analysis, and analyses of development and growth; and experimental investigations of call functions.

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“…For several decades, Pacific walrus ( Odobenus rosmarus divergens ) monitoring at coastal haulouts has been a significant source of information on its population abundance, demographic structure, and vital rates including birth rates, calf survival, and mortality [ 1 – 13 ]. Researchers have conducted biological and ecological studies, which serve as the foundation for current understanding of walrus behavior [ 14 – 16 ]. These studies have traditionally relied on visual observations of walruses aggregating on the coast during the summer and fall months, with observers carrying out walrus head counts and demographic surveys [ 7 , 13 , 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

Enhancing the accuracy and efficiency of Pacific walrus (Odobenus rosmarus divergens) surveys: A comparison of visual and aerial imagery-based counts at coastal haulouts

Altukhov,

Kryukova,

Trukhanova

et al. 2024

PLoS ONE

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This study presents a semi-automated approach utilizing unoccupied aerial vehicle (UAV) surveys to accurately estimate the abundance of Pacific walruses at large coastal haulouts in Chukotka, Russia. Seven major haulout sites were surveyed during the summers and falls of 2017–2019. Walrus counts were performed using three distinct methods: traditional visual land-based counts, complete head counts utilizing georeferenced UAV imagery, and counting walruses within model polygons within the haulout outline and employing various extrapolation techniques to predict walrus abundance across the haulout area. The results indicated that traditional visual counts neither yielded consistent results nor allowed for uncertainty estimation, unlike the site- and date-specific direct extrapolation method and the non-specific linear regression model. These latter methods consistently provided estimates, on average, within 5% of the "true" abundance determined through complete photo-based head counts. Beside yielding accurate estimates, these semi-automated methods significantly reduced counting time by at least 63%, in contrast to complete head counts. The non-specific model, which allowed the estimation of walrus abundance based on the type of the terrain and the haulout area was less accurate compared with site and date specific estimates, but provided a tool to estimate abundance when no field visits are conducted, e.g., by using high-resolution satellite imagery to measure haulout area. This model revealed that the haulouts located on flat sandy beaches exhibited mean walrus densities approximately 30.5% times higher than those on rocky shores surrounded by cliffs: 0.879 (SD = 0.1302) and 0.648 (SD = 0.1753) walrus per m2 correspondingly. The estimated daily walrus abundance at major Chukotkan haulouts in 2017–2019 ranged between 15 and 94,660 (mean = 10,397, SD = 14,477) walruses with the maximum seasonal abundances reported at Cape Serdtse-Kamen as 94,960 on 10-Oct-2017, 26,850 on 10-Oct-2018, and 87,595 on 10-Oct-2019.

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Ethology and Behavioral Ecology of the Walrus (Odobenus rosmarus), with Emphasis on Communication and Social Behavior

Cited by 6 publications

References 160 publications

Passive acoustics suggest two different feeding mechanisms in the Atlantic walrus (Odobenus rosmarus rosmarus)

Passive acoustics suggest two different feeding mechanisms in the Atlantic walrus (Odobenus rosmarus rosmarus)

Anatomy of avian distress calls: structure, variation, and complexity in two species of shorebird (Aves: Charadrii)

Enhancing the accuracy and efficiency of Pacific walrus (Odobenus rosmarus divergens) surveys: A comparison of visual and aerial imagery-based counts at coastal haulouts

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