Lifetime reproductive success of northern elephant seals (Mirounga angustirostris)

2019 ◽  
Vol 97 (12) ◽  
pp. 1203-1217 ◽  
Author(s):  
Burney Le Boeuf ◽  
Richard Condit ◽  
Joanne Reiter
Keyword(s):  
Life History ◽  
Reproductive Success ◽  
Natural Population ◽  
Lifetime Reproductive Success ◽  
Mirounga Angustirostris ◽  
Elephant Seals ◽  
Young Females ◽  
Darwinian Fitness ◽  
Northern Elephant Seals ◽  
Selection For

Lifetime reproductive success of individuals in a natural population provides an estimate of Darwinian fitness. We calculated lifetime reproductive success in a colony of female northern elephant seals (Mirounga angustirostris (Gill, 1866)) by monitoring annual breeding throughout life of 7735 female weanlings marked individually at Año Nuevo, California, USA, from 1963 to 2005. Great variation in lifetime reproductive success was evident in three aspects of life history: (1) 75% of the females died before reaching breeding age and produced no pups; (2) nearly half of the survivors bred for only a few years before dying, and young females had low weaning success; (3) less than 1% of the females in the sample were exceptionally successful producing up to 20 pups in life. Many females that bred early, while still growing, had decreased lifespan, low weaning success, and lower lifetime reproductive success than females that postponed first breeding. Exceptional reproductive success was associated with giving birth annually, living long (up to age 23), and weaning large pups that were more likely to survive and breed. We conclude that there is strong selection for increased lifespan and multiparous supermoms that contribute significantly to pup production in the next generation.

Aggression in the Female Northern Elephant Seal, Mirounga Angustirostris

Behaviour ◽  
1978 ◽  
Vol 64 (1-2) ◽  
pp. 158-171 ◽  
Author(s):  
T.E. Christenson ◽  
B.J. Le Boeuf
Keyword(s):  
Reproductive Success ◽  
Aggressive Behavior ◽  
Elephant Seal ◽  
Mirounga Angustirostris ◽  
Northern Elephant Seal ◽  
Elephant Seals ◽  
Advantages And Disadvantages ◽  
Northern Elephant Seals ◽  
Pup Survival ◽  
Male Activity

AbstractMaternal aggressive behavior of northern elephant seals enhances reproductive success by increasing the likelihood of pup survival. Detailed observations of marked mother-pup pairs revealed that female aggressiveness increased dramatically after giving birth. Maternal aggressiveness also correlated negatively with the number of times the pup was bitten by alien females. Mothers of these pups were less aggressive than the 17 whose pups survived. Pup behavior was not directly related to mortality. Frequencies of interfemale aggressive encounters were compared for different beach areas. Aggression was most frequent on the smallest area, where interfemale distance was the shortest, and tidal action extreme. Aggression was least frequent on the sparcely populated beach, affected little by tide or male activity. Interfemale distance was greatest here. Reproductive advantages and disadvantages of pupping on each area are noted.

scholarly journals Foraging and fasting can influence contaminant concentrations in animals: an example with mercury contamination in a free-ranging marine mammal

2018 ◽  
Vol 285 (1872) ◽  
pp. 20172782 ◽  
Author(s):  
Sarah H. Peterson ◽  
Joshua T. Ackerman ◽  
Daniel E. Crocker ◽  
Daniel P. Costa
Keyword(s):  
Life History ◽  
Mercury Contamination ◽  
Mirounga Angustirostris ◽  
Elephant Seals ◽  
Northern Elephant Seals ◽  
Large Fluctuations ◽  
Before And After ◽  
Blood Mercury ◽  
Annual Life History ◽  
Free Ranging

Large fluctuations in animal body mass in relation to life-history events can influence contaminant concentrations and toxicological risk. We quantified mercury concentrations in adult northern elephant seals ( Mirounga angustirostris ) before and after lengthy at sea foraging trips ( n = 89) or fasting periods on land ( n = 27), and showed that mercury concentrations in blood and muscle changed in response to these events. The highest blood mercury concentrations were observed after the breeding fast, whereas the highest muscle mercury concentrations were observed when seals returned to land to moult. Mean female blood mercury concentrations decreased by 30% across each of the two annual foraging trips, demonstrating a foraging-associated dilution of mercury concentrations as seals gained mass. Blood mercury concentrations increased by 103% and 24% across the breeding and moulting fasts, respectively, demonstrating a fasting-associated concentration of mercury as seals lost mass. In contrast to blood, mercury concentrations in female's muscle increased by 19% during the post-breeding foraging trip and did not change during the post-moulting foraging trip. While fasting, female muscle mercury concentrations increased 26% during breeding, but decreased 14% during moulting. Consequently, regardless of exposure, an animal's contaminant concentration can be markedly influenced by their annual life-history events.

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.

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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