scholarly journals Blood dynamics of mercury and selenium in northern elephant seals during the lactation period

2011 ◽  
Vol 159 (10) ◽  
pp. 2523-2529 ◽  
Author(s):  
Sarah Habran ◽  
Cathy Debier ◽  
Daniel E. Crocker ◽  
Dorian S. Houser ◽  
Krishna Das
Keyword(s):  
Lactation Period ◽  
Elephant Seals ◽  
Northern Elephant Seals

Mass transfer from mother to pup and subsequent mass loss by the weaned pup in the hooded seal, Cystophora cristata

1987 ◽  
Vol 65 (1) ◽  
pp. 1-8 ◽  
Author(s):  
W. D. Bowen ◽  
D. J. Boness ◽  
O. T. Oftedal
Keyword(s):  
Mass Transfer ◽  
Weight Loss ◽  
Body Weight ◽  
Lactation Period ◽  
Fasting Period ◽  
Hooded Seal ◽  
Elephant Seals ◽  
Cystophora Cristata ◽  
Northern Elephant Seals ◽  
Efficient Transfer

We studied the components of mass transfer from mother to pup during the lactation period and weight loss by fasting pups postweaning in the hooded seal, Cystophora cristata. Measurements were taken from 33 mother–pup pairs and 69 weaned pups. Mean body weight of mothers declined from an average of 179 kg at the beginning of lactation to 150 kg for mothers nursing fat pups near the end of lactation. Over 80% of this weight loss was from the sculp (i.e., skin and blubber). Pup weight doubled during the 4 days of lactation, with about 70% of this weight gain in the form of blubber. Fasting pups lost 29% or 13 kg of their body weight between weaning and mid to late April when feeding begins. Sculp and core weight accounted for 51% and 49%, respectively, of total weight loss during this fasting period. Hooded seal mothers invest a smaller portion of their stored fat (33%) in their pup than do grey seals (85%) and northern elephant seals (58%). Our hooded seal data are consistent with the hypothesis that the abbreviation of lactation allows a reduction in overhead costs and more efficient transfer of nutrients from mother to pup.

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

Ten. Sex- and age-related variation in reproductive effort of northern elephant seals

1994 ◽  
pp. 169-210 ◽  
Author(s):  
Charles J. Deutsch ◽  
Daniel E. Crocker ◽  
Daniel P. Costa ◽  
Burney J. Le Boeuf
Keyword(s):  
Reproductive Effort ◽  
Elephant Seals ◽  
Related Variation ◽  
Age Related ◽  
Northern Elephant Seals

scholarly journals Correction to ‘The rise and fall of dialects in northern elephant seals’

2019 ◽  
Vol 286 (1895) ◽  
pp. 20182912
Author(s):  
Caroline Casey ◽  
Colleen Reichmuth ◽  
Daniel P. Costa ◽  
Burney Le Boeuf
Keyword(s):  
Elephant Seals ◽  
Northern Elephant Seals
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