scholarly journals The effect of a low-frequency sound source (acoustic thermometry of the ocean climate) on the diving behavior of juvenile northern elephant seals,Mirounga angustirostris

2003 ◽  
Vol 113 (2) ◽  
pp. 1155-1165 ◽  
Author(s):  
Daniel P. Costa ◽  
Daniel E. Crocker ◽  
Jason Gedamke ◽  
Paul M. Webb ◽  
Dorian S. Houser ◽  
...  
Keyword(s):  
Sound Source ◽  
Low Frequency ◽  
Diving Behavior ◽  
Mirounga Angustirostris ◽  
Elephant Seals ◽  
Ocean Climate ◽  
Frequency Sound ◽  
Acoustic Thermometry ◽  
Northern Elephant Seals

Diving behavior in relation to ambient water temperature in northern elephant seals

1994 ◽  
Vol 72 (4) ◽  
pp. 643-651 ◽  
Author(s):  
Hiroshi Hakoyama ◽  
Burney J. Le Boeuf ◽  
Yasuhiko Naito ◽  
Wataru Sakamoto
Keyword(s):  
Water Temperature ◽  
Elephant Seal ◽  
Diving Behavior ◽  
Mirounga Angustirostris ◽  
Ambient Water ◽  
Northern Elephant Seal ◽  
Elephant Seals ◽  
Northern Elephant Seals ◽  
Abrupt Changes ◽  
Ambient Water Temperature

Our aim was to describe changes in ambient water temperature during the course of migration by northern elephant seals (Mirounga angustirostris) and to examine evidence for the seal using abrupt temperature gradients for locating prey. During migration in the post breeding season, the diving patterns of 10 adult females and 7 breeding-age males from Año Nuevo, California, were recorded with time–depth recorders in 1989–1991. Recorded sea surface temperatures declined from 11–13 °C to a low of 3–9 °C as the seals moved north and increased as they returned. Depth of diving was not closely linked to sharp thermal gradients. A thermocline was evident only at the beginning and end of the migration in less than 100 m of water, where less than 2% of diving takes place. There were sex differences in the temperature range at the depths where 75% of diving and foraging occurred, owing in part to habitat separation. The temperatures were lower and the range narrower for females (4.2–5.2 °C at 388–622 m) than for males (5.3–6.0 °C at 179–439 m). We conclude that the northern elephant seal habitat does not provide abrupt changes in temperature that might serve as important cues for locating prey.

Diving behavior of juvenile northern elephant seals

1996 ◽  
Vol 74 (9) ◽  
pp. 1632-1644 ◽  
Author(s):  
Burney J. Le Boeuf ◽  
Patricia A. Morris ◽  
Susanna B. Blackwell ◽  
Daniel E. Crocker ◽  
Daniel P. Costa
Keyword(s):  
Sex Differences ◽  
Diving Behavior ◽  
Mirounga Angustirostris ◽  
Physiological Changes ◽  
Elephant Seals ◽  
The Third ◽  
Northern Elephant Seals ◽  
Foraging Pattern ◽  
Age And Sex ◽  
Benthic Prey

We describe and review the development of the diving and foraging pattern of northern elephant seals, Mirounga angustirostris, during migrations over the first 2 years of life. The diving pattern and migratory tracks of 23 juveniles, 9–27 months of age, from Año Nuevo and Piedras Blancas, California, were recorded with attached time–depth recorders and Argos satellite tags. The seals exhibited a general diving pattern like that of adults, diving deep (373 ± 77 m per dive (mean ± SD)), long (15.2 ± 2.6 min per dive), and continuously (88.7 ± 2.7% of the time submerged while at sea). Level of performance increased with age and experience up to 2 years of age, the end of the fourth migration, when modal diving performance was equal to that of adults. Juveniles migrated north to the waters west of Oregon, Washington, and British Columbia, moving more slowly and not as far as adults. By the third trip to sea, males began to exhibit more flat-bottomed dives than females, a sex difference observed in adults, suggesting that males supplement a diet of pelagic organisms with benthic prey. These data and related observations of elephant seals suggest that the greatest physiological changes enabling an animal to dive occur near the rookery following weaning, before the first trip to sea; transition to a pelagic existence is difficult, as reflected by high mortality during the first migration; improvement of diving skills continues up to 2 years of age; and sex differences in foraging behavior and foraging location, similar to those seen in adults, are evident before the seals reach 2 years of age.

Low-Frequency Sound Source with Dual Bending Radiation Surfaces

1998 ◽  
Vol 37 (Part 1, No. 5B) ◽  
pp. 3161-3165 ◽  
Author(s):  
Mitsuru Yamamoto ◽  
Hiroshi Ishimura ◽  
Yoshinori Hama ◽  
Takeshi Inoue
Keyword(s):  
Sound Source ◽  
Low Frequency ◽  
Frequency Sound

scholarly journals The rise and fall of dialects in northern elephant seals

2018 ◽  
Vol 285 (1892) ◽  
pp. 20182176 ◽  
Author(s):  
Caroline Casey ◽  
Colleen Reichmuth ◽  
Daniel P. Costa ◽  
Burney Le Boeuf
Keyword(s):  
Mammalian Species ◽  
Structural Complexity ◽  
Mirounga Angustirostris ◽  
Geographical Differences ◽  
Migration Patterns ◽  
Elephant Seals ◽  
The North ◽  
Vocal Behaviour ◽  
Northern Elephant Seals ◽  
The North Pacific

Vocal dialects are fundamental to our understanding of the transmission of social behaviours between individuals and populations, however few accounts trace this phenomenon among mammals over time. Northern elephant seals ( Mirounga angustirostris ) provide a rare opportunity to examine the trajectory of dialects in a long-lived mammalian species. Dialects were first documented in the temporal patterns of the stereotyped vocal displays produced by breeding males at four sites in the North Pacific in 1968 and 1969, as the population recovered from extreme exploitation. We evaluated the longevity of these geographical differences by comparing these early recordings to calls recently recorded at these same locations. While the presence of vocal dialects in the original recordings was re-confirmed, geographical differences in vocal behaviour were not found at these breeding rookeries nearly 50 years later. Moreover, the calls of contemporary males displayed more structural complexity after approximately four generations, with substantial between-individual variation and call features not present in the historical data. In the absence of measurable genetic variation in this species—owing to an extreme population bottleneck—a combination of migration patterns and cultural mutation are proposed as factors influencing the fall of dialects and the dramatic increase in call diversity.

Subjective evaluation of the combining effect between the virtual bass and head related transfer functions

2021 ◽  
Vol 263 (5) ◽  
pp. 1488-1496
Author(s):  
Yunqi Chen ◽  
Chuang Shi ◽  
Hao Mu
Keyword(s):  
Fundamental Frequency ◽  
Sound Source ◽  
Transfer Functions ◽  
Subjective Evaluation ◽  
Low Frequency ◽  
Localization Accuracy ◽  
Frequency Sound ◽  
Listening Tests ◽  
Listening Experience ◽  
Missing Fundamental

Earphones are commonly equipped with miniature loudspeaker units, which cannot transmit enough power of low-frequency sound. Meanwhile, there is often only one loudspeaker unit employed on each side of the earphone, whereby the multi-channel spatial audio processing cannot be applied. Therefore, the combined usage of the virtual bass (VB) and head-related transfer functions (HRTFs) is necessary for an immersive listening experience with earphones. However, the combining effect of the VB and HRTFs has not been comprehensively reported. The VB is developed based on the missing fundamental effect, providing that the presence of harmonics can be perceived as their fundamental frequency, even if the fundamental frequency is not presented. HRTFs describe the transmission process of a sound propagating from the sound source to human ears. Monaural audio processed by a pair of HRTFs can be perceived by the listener as a sound source located in the direction associated with the HRTFs. This paper carries out subjective listening tests and their results reveal that the harmonics required by the VB should be generated in the same direction as the high-frequency sound. The bass quality is rarely distorted by the presence of HRTFs, but the localization accuracy is occasionally degraded by the VB.

The effect of rehabilitation of northern elephant seals (Mirounga angustirostris) on antimicrobial resistance of commensal Escherichia coli

2009 ◽  
Vol 133 (3) ◽  
pp. 264-271 ◽  
Author(s):  
Robyn A. Stoddard ◽  
E. Rob Atwill ◽  
Patricia A. Conrad ◽  
Barbara A. Byrne ◽  
Spencer Jang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Mirounga Angustirostris ◽  
Elephant Seals ◽  
Northern Elephant Seals

scholarly journals Rival assessment among northern elephant seals: evidence of associative learning during male–male contests

2015 ◽  
Vol 2 (8) ◽  
pp. 150228 ◽  
Author(s):  
Caroline Casey ◽  
Isabelle Charrier ◽  
Nicolas Mathevon ◽  
Colleen Reichmuth
Keyword(s):  
Communication Strategy ◽  
Social Knowledge ◽  
Mirounga Angustirostris ◽  
Alternative Communication ◽  
Elephant Seals ◽  
Acoustic Signatures ◽  
Dominance Relationships ◽  
Northern Elephant Seals ◽  
Rival Assessment ◽  
Male Contests

Specialized signals emitted by competing males often convey honest information about fighting ability. It is generally believed that receivers use these signals to directly assess their opponents. Here, we demonstrate an alternative communication strategy used by males in a breeding system where the costs of conflict are extreme. We evaluated the acoustic displays of breeding male northern elephant seals ( Mirounga angustirostris ), and found that social knowledge gained through prior experience with signallers was sufficient to maintain structured dominance relationships. Using sound analysis and playback experiments with both natural and modified signals, we determined that males do not rely on encoded information about size or dominance status, but rather learn to recognize individual acoustic signatures produced by their rivals. Further, we show that behavioural responses to competitors' calls are modulated by relative position in the hierarchy: the highest ranking (alpha) males defend their harems from all opponents, whereas mid-ranking (beta) males respond differentially to familiar challengers based on the outcome of previous competitive interactions. Our findings demonstrate that social knowledge of rivals alone can regulate dominance relationships among competing males within large, spatially dynamic social groups, and illustrate the importance of combining descriptive and experimental methods when deciphering the biological relevance of animal signals.

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