Do male northern elephant seals recognize individuals or merely relative dominance rank?

2012 ◽  
Vol 131 (1) ◽  
pp. EL35-EL41 ◽  
Author(s):  
Stephen J. Insley ◽  
Marla M. Holt
Keyword(s):  
Dominance Rank ◽  
Elephant Seals ◽  
Relative Dominance ◽  
Northern Elephant Seals

Reproductive effort of male northern elephant seals: estimates from mass loss

1990 ◽  
Vol 68 (12) ◽  
pp. 2580-2593 ◽  
Author(s):  
Charles J. Deutsch ◽  
Michael P. Haley ◽  
Burney J. Le Boeuf
Keyword(s):  
Body Size ◽  
Mass Loss ◽  
Breeding Season ◽  
Reproductive Effort ◽  
Dominance Rank ◽  
Adult Males ◽  
Age Classes ◽  
Elephant Seals ◽  
High Ranking ◽  
Northern Elephant Seals

The energetic component of reproductive effort of male northern elephant seals, Mirounga angustirostris, was estimated from mass loss over the breeding season and correlated with dominance rank and age. Fifty-four unrestrained bulls were weighed on a platform scale by luring them with a model of a female seal or moving them with a tarpaulin and using playback of male aggressive vocalizations. Adult males weighed up to 2300 kg upon arrival at the breeding rookery. Mean rate of mass loss during the breeding season was 7.1 ± 1.5 (SD) and 4.6 ± 0.8 kg per day for 17 adults and 13 subadults, respectively. Rate of mass loss was positively correlated with body size (mass or length) for both age-classes. Mass-specific rate of mass loss did not differ between age-classes but increased with increasing dominance rank among adult males. Reproductive effort, expressed as percentage of body mass lost over the 3-month breeding season, was greater for high-ranking bulls (mean 41.4%) than for low-ranking adults (33.8%), but was not related to age-class or body size. High-ranking males experienced higher mating success and expended more energy than subordinate males. Comparison with a previous study on conspecific females indicates that mass-specific energetic investment in reproduction is similar for both sexes, despite marked sex differences in reproductive strategy and duration of effort.

Vocal signaling among male northern elephant seals: Behavioral field studies of honesty vs. associative learning

2012 ◽  
Author(s):  
Colleen Reichmuth ◽  
Caroline Casey ◽  
Isabelle Charrier ◽  
Nicolas Mathevon ◽  
Brandon Southall
Keyword(s):  
Associative Learning ◽  
Field Studies ◽  
Elephant Seals ◽  
Northern Elephant Seals ◽  
Vocal Signaling

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.

Gluconeogenesis is associated with high rates of tricarboxylic acid and pyruvate cycling in fasting northern elephant seals

2012 ◽  
Vol 303 (3) ◽  
pp. R340-R352 ◽  
Author(s):  
Cory D. Champagne ◽  
Dorian S. Houser ◽  
Melinda A. Fowler ◽  
Daniel P. Costa ◽  
Daniel E. Crocker
Keyword(s):  
Phosphoenolpyruvate Carboxykinase ◽  
Glucose Production ◽  
Tca Cycle ◽  
Tricarboxylic Acid ◽  
Endogenous Glucose Production ◽  
Large Contribution ◽  
Protein Loss ◽  
Elephant Seals ◽  
Pyruvate Cycling ◽  
Northern Elephant Seals

Animals that endure prolonged periods of food deprivation preserve vital organ function by sparing protein from catabolism. Much of this protein sparing is achieved by reducing metabolic rate and suppressing gluconeogenesis while fasting. Northern elephant seals ( Mirounga angustirostris) endure prolonged fasts of up to 3 mo at multiple life stages. During these fasts, elephant seals maintain high levels of activity and energy expenditure associated with breeding, reproduction, lactation, and development while maintaining rates of glucose production typical of a postabsorptive mammal. Therefore, we investigated how fasting elephant seals meet the requirements of glucose-dependent tissues while suppressing protein catabolism by measuring the contribution of glycogenolysis, glycerol, and phosphoenolpyruvate (PEP) to endogenous glucose production (EGP) during their natural 2-mo postweaning fast. Additionally, pathway flux rates associated with the tricarboxylic acid (TCA) cycle were measured specifically, flux through phosphoenolpyruvate carboxykinase (PEPCK) and pyruvate cycling. The rate of glucose production decreased during the fast (F1,13= 5.7, P = 0.04) but remained similar to that of postabsorptive mammals. The fractional contributions of glycogen, glycerol, and PEP did not change with fasting; PEP was the primary gluconeogenic precursor and accounted for ∼95% of EGP. This large contribution of PEP to glucose production occurred without substantial protein loss. Fluxes through the TCA cycle, PEPCK, and pyruvate cycling were higher than reported in other species and were the most energetically costly component of hepatic carbohydrate metabolism. The active pyruvate recycling fluxes detected in elephant seals may serve to rectify gluconeogeneic PEP production during restricted anaplerotic inflow in these fasting-adapted animals.

scholarly journals Prolonged fasting increases purine recycling in post-weaned northern elephant seals

2012 ◽  
Vol 215 (9) ◽  
pp. 1448-1455 ◽  
Author(s):  
J. G. Sonanez-Organis ◽  
J. P. Vazquez-Medina ◽  
T. Zenteno-Savin ◽  
A. Aguilar ◽  
D. E. Crocker ◽  
...  
Keyword(s):  
Prolonged Fasting ◽  
Elephant Seals ◽  
Northern Elephant Seals
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