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

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.

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

Royal Society Open Science ◽

10.1098/rsos.150228 ◽

2015 ◽

Vol 2 (8) ◽

pp. 150228 ◽

Cited By ~ 18

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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Vocal recognition of individuals versus relative dominance rank among breeding male northern elephant seals (Mirounga angustirostris).

The Journal of the Acoustical Society of America ◽

10.1121/1.3588274 ◽

2011 ◽

Vol 129 (4) ◽

pp. 2505-2505

Author(s):

Stephen J. Insley ◽

Marla M. Holt ◽

Brandon L. Southall

Keyword(s):

Dominance Rank ◽

Mirounga Angustirostris ◽

Elephant Seals ◽

Relative Dominance ◽

Northern Elephant Seals ◽

Vocal Recognition

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Plasma carnitine in fasting neonatal and adult northern elephant seals

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1992.263.3.e570 ◽

1992 ◽

Vol 263 (3) ◽

pp. E570-E574

Author(s):

S. H. Adams ◽

D. P. Costa ◽

S. C. Winter

Keyword(s):

Fatty Acid ◽

Acid Oxidation ◽

Mirounga Angustirostris ◽

Elephant Seals ◽

Plasma Carnitine ◽

Adult Females ◽

Naturally Occurring ◽

Northern Elephant Seals ◽

Free Fatty Acid Oxidation ◽

The Impact

Maintenance of adequate body carnitine stores is a requisite for fasting mammals, whose energy is derived mainly from free fatty acid oxidation. The impact of longterm fasting on carnitine status is unclear, and there have been no reports of carnitine during naturally occurring fasts. Total (TC), free (FC), and acylated (AC) plasma carnitine levels were determined in 10 weaned and 11 adult northern elephant seals (Mirounga angustirostris) during natural fasts lasting from 1 to 3 mo. In pups, TC declined little and AC increased only slightly [P greater than 0.05, analysis of variance (ANOVA)] through 11 wk of fasting. Plasma FC dropped by 53 and 26% from week 1 values at 10 and 11 wk fasting, respectively (P = 0.014, ANOVA). The AC/FC ratio did not approach 1.0 until 7 wk of fasting. TC was 38.6 +/- 1.4 microM and 47.6 +/- 4.1 microM in adult females and males, respectively. Adult AC/FC ratios were 0.71 +/- 0.10 (females) and 0.08 +/- 0.04 (males). Plasma TC status is not negatively affected by extended fasting in adult and weaned northern elephant seals. These data support the hypothesis that fasting northern elephant seals defend plasma TC and maintain an attenuated AC/FC ratio well into their prolonged natural fast.

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