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.

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 Treatment of Canine Tooth Fractures in the Northern Elephant Seal (Mirounga angustirostris): Three Cases

2019 ◽  
Vol 36 (1) ◽  
pp. 52-61
Author(s):  
Deborah L. Hodesson ◽  
Judy Force ◽  
Sophie Whoriskey ◽  
Cara Field
Keyword(s):  
Maternal Separation ◽  
Case Series ◽  
Elephant Seal ◽  
Anthropogenic Factors ◽  
Mirounga Angustirostris ◽  
Canine Tooth ◽  
Northern Elephant Seal ◽  
Elephant Seals ◽  
Northern Elephant Seals ◽  
Pulp Exposure

The Marine Mammal Center (TMMC) in Sausalito, California, rescues, rehabilitates, and releases hundreds of stranded northern elephant seals ( Mirounga angustirostris) each year. Common causes for stranding include maternal separation, malnutrition, and trauma. Causes of trauma include shark bites, conspecific interactions, and anthropogenic factors. Several cases of fractured teeth, secondary to presumed trauma, are presented to the center each year. This case series describes surgical approach and treatment of 3 young northern elephant seals that were admitted to TMMC for rehabilitation with tooth fractures with pulp exposure of maxillary or mandibular canine teeth. All 3 seals were successfully released into their natural environment.

scholarly journals Creation Nerves of the Lumbar and Sacral Plexus in California Sea Lions (Zalophus Californianus) and Northern Elephant Seals (Mirounga Angustirostris)/Formiranje Nerava Iz Lumbalnog I Sakralnog Pleksusa Kod Kalifornijskog Morskog Lava (Zalophus Californianus) I Severnomorskog Slona (Mirounga Angustirostris)

2014 ◽  
Vol 64 (3) ◽  
pp. 293-306 ◽  
Author(s):  
Mihelić Damir ◽  
Smodlaka Hrvoje ◽  
Tkalčić Suzana ◽  
Palmer Lauren ◽  
Mršić Gordan ◽  
...  
Keyword(s):  
Femoral Nerve ◽  
Elephant Seal ◽  
Zalophus Californianus ◽  
Mirounga Angustirostris ◽  
California Sea Lions ◽  
Northern Elephant Seal ◽  
Elephant Seals ◽  
Sea Lions ◽  
Northern Elephant Seals ◽  
Sacral Nerves

Abstract The lumbosacral plexus was investigated in the California sea lion and Northern elephant seal. In 9 California sea lions and 2 Northern elephant seals the femoral nerve rises from the ventral branches of the 3rd and 4th lumbar nerves, whilst in one male and two specimens of the Northern elephant seal the 5th lumbar nerve was also involved. Ventral branches of the 3rd and 4th lumbar nerves comprised the obturatorius nerve in 7 specimens; in 3 specimens the 5th lumbar nerve additionally supplements the obturatorius nerve. In Northern elephant seals the obturatorius nerve originates from the ventral branches of the 3rd, 4th and 5th lumbar nerves. The ischiadic nerve originates from the ventral branches of the 4th, 5th lumbar and 1st sacral nerves in 8 specimens California sea lions and in 2 North elephant seals. In 2 specimens of both species the 2nd sacral nerve also participates. The gluteal nerve created ventral branches of the 5th lumbar and 1st sacral nerves in three specimens; however in one specimen the 4th and 5th lumbar nerves gave rise to the same nerve in the Northern elephant seal. In California sea lions the gluteal nerve originates from the ventral branches of the 5th lumbar nerve in seven specimens, nonetheless in 3 specimens the 4th lumbar nerve also participates in its formation.

scholarly journals Where were the northern elephant seals? Holocene archaeology and biogeography of Mirounga angustirostris

The Holocene ◽  
2011 ◽  
Vol 21 (7) ◽  
pp. 1159-1166 ◽  
Author(s):  
Torben C. Rick ◽  
Robert L. DeLong ◽  
Jon M. Erlandson ◽  
Todd J. Braje ◽  
Terry L. Jones ◽  
...  
Keyword(s):  
Nineteenth Century ◽  
Elephant Seal ◽  
Archaeological Sites ◽  
Mirounga Angustirostris ◽  
Northern Elephant Seal ◽  
Elephant Seals ◽  
The Holocene ◽  
Archaeological Data ◽  
Large Numbers ◽  
Northern Elephant Seals

Driven to the brink of extinction during the nineteenth century commercial fur and oil trade, northern elephant seal (NES, Mirounga angustirostris) populations now exceed 100 000 animals in the northeast Pacific from Alaska to Baja California. Because little is known about the biogeography and ecology of NES prior to the mid-nineteenth century, we synthesize and analyze the occurrence of NES remains in North American archaeological sites. Comparing these archaeological data with modern biogeographical, genetic, and behavioral data, we provide a trans-Holocene perspective on NES distribution and abundance. Compared with other pinnipeds, NES bones are relatively rare throughout the Holocene, even in California where they currently breed in large numbers. Low numbers of NES north of California match contemporary NES distribution, but extremely low occurrences in California suggest their abundance in this area was very different during the Holocene than today. We propose four hypotheses to explain this discrepancy, concluding that ancient human settlement and other activities may have displaced NES from many of their preferred modern habitats during much of the Holocene.

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.

Blood viscosity and optimal hematocrit in a deep-diving mammal, the northern elephant seal (Mirounga angustirostris)

1986 ◽  
Vol 64 (10) ◽  
pp. 2081-2085 ◽  
Author(s):  
Michael S. Hedrick ◽  
Deborah A. Duffield ◽  
Lanny H. Cornell
Keyword(s):  
Oxygen Transport ◽  
Blood Viscosity ◽  
Storage Capacity ◽  
Oxygen Storage Capacity ◽  
Elephant Seal ◽  
Oxygen Storage ◽  
Diving Behavior ◽  
Northern Elephant Seal ◽  
Elephant Seals ◽  
Deep Diving

Elephant seals offer a unique opportunity to examine rheological characteristics of blood because of the normally high hematocrits in this species. A comparison of blood viscosity of the elephant seal with that of a terrestrial mammal (rabbit; HCT = 35%) reveals a threefold increase in viscosity of elephant seal blood over that of rabbit blood due to the high hematocrit (HCT = 65%). While the increased hematocrit of elephant seal blood reflects increased oxygen storage capacity, blood oxygen transport may actually be reduced by the effects of increased blood viscosity on blood flow. Elephant seal plasma viscosity was also higher than that of rabbit plasma; this was associated with a higher concentration of plasma proteins. There were no apparent differences in the viscous properties of the red blood cells of the two species. The theoretically optimal hematocrit was determined in vitro for reconstituted blood from each species and compared with the observed in vivo hematocrit. It was found that the observed hematocrit of the elephant seal lies far to the right of the predicted hematocrit for optimal oxygen transport, while the rabbit hematocrit was identical with the predicted value. These results suggest that elephant seals have increased oxygen storage capacity at the expense of optimizing oxygen transport. The observed increase in hematocrit and viscosity may be of importance in considering the diving behavior and energetics of elephant seals.

Multifocal Necrotizing Myopathy in Northern Elephant Seal (Mirounga angustirostris) Pups, San Miguel Island, California

2018 ◽  
Vol 56 (1) ◽  
pp. 143-151 ◽  
Author(s):  
Terry R. Spraker ◽  
Tetiana A. Kuzmina ◽  
Eugene T. Lyons ◽  
Robert L. DeLong ◽  
Claire Simeone ◽  
...  
Keyword(s):  
Elephant Seal ◽  
Mirounga Angustirostris ◽  
Northern Elephant Seal ◽  
Vacuolar Degeneration ◽  
Necrotizing Myopathy ◽  
Eosinophilic Cytoplasm ◽  
Northern Elephant Seals ◽  
San Miguel Island ◽  
System Degeneration ◽  
Causes Of Mortality

A field study addressing causes of mortality in freshly dead northern elephant seals ( Mirounga angustirostris, Gill, 1866) was conducted on San Miguel Island, California, in February 2015. Necropsies were performed on 18 pups ranging in age from stillbirths to approximately 7 to 8 weeks. The primary gross diagnoses in these pups included trauma, myopathy, starvation/emaciation, infections, congenital anomalies, and perinatal mortality. However, 6 (33%) had a previously unrecognized myopathy characterized by multiple white streaks that were most obvious within the inner layer of the abdominal wall and the small innermost ventral intercostal muscles. Following histological examination, 2 more pups from San Miguel Island and 6 pups from The Marine Mammal Center (Sausalito, California) were found to have similar lesions. Histologically, the lesions within the skeletal muscles were characterized by a multifocal polyphasic, mild to severe, acute to subacute necrotizing myopathy with mineralization. Acute necrosis and degeneration characterized by pyknotic nuclei, eosinophilic cytoplasm and cytoplasmic vacuolization were found in smooth muscle myocytes within the urinary bladder and digestive system. Degeneration of myocytes was present in the tunica media of a few small- to medium-sized vessels and was characterized by a vacuolar degeneration and occasionally necrosis. This condition has been termed multifocal necrotizing myopathy. A cause of this myopathy was not identified.

Mother-Offspring Separation and Acoustic Stereotypy: a Comparison of Call Morphology in Two Species of Pinnipeds

Behaviour ◽  
1992 ◽  
Vol 120 (1-2) ◽  
pp. 103-122 ◽  
Author(s):  
Stephen J. Insley
Keyword(s):  
Individual Variation ◽  
Elephant Seal ◽  
Mirounga Angustirostris ◽  
Northern Fur Seal ◽  
Northern Elephant Seal ◽  
Fur Seals ◽  
Fur Seal ◽  
Species Analysis ◽  
Northern Elephant Seals ◽  
Discriminant Analyses

AbstractI have compared structural variation of the primary vocalizations used between mother-offspring pairs in two species of pinnipeds that differ fundamentally in their breeding behaviour: northern elephant seal (Mirounga angustirostris) mothers and offspring normally are together throughout the nursing period; northern fur seal (Callorhinus ursinus) females regularly separate from their offspring while nursing. Two predictions were tested: (1) these vocalizations should be individually-distinct (stereotyped) in females and pups of both species if they serve to function for recognition, and (2) because individuality should be more pronounced in a species where separations and reunions are common, the vocalizations used between northern fur seal mother-offspring pairs should be more individually-stereotyped than those of the northern elephant seal. Principal components analyses revealed structural differences between the calls of females and pups in both species. Analysis of variance showed the calls of individual seals to be acoustically distinct in all cases. The calls used between mother-offspring pairs of northern fur seals were more stereotyped than those of northern elephant seals. These calls had less within-individual variation, greater among-individual variation and were more often correctly predicted in discriminant analyses. The results indicate that selective pressure to develop vocal recognition exists in both species but is greater in the northern fur seal.

Sexual Behavior in the Northern Elephant Seal Mirounga Angustirostris

Behaviour ◽  
1972 ◽  
Vol 41 (1-2) ◽  
pp. 1-26 ◽  
Author(s):  
Burney J. Leboeuf
Keyword(s):  
Social Systems ◽  
Elephant Seal ◽  
Social Hierarchy ◽  
Mirounga Angustirostris ◽  
Northern Elephant Seal ◽  
Female Behavior ◽  
Elephant Seals ◽  
Sea Lions ◽  
The Social ◽  
Breeding Seasons

AbstractThe mating behavior of Northern elephant seals, Mirounga angustirostris, was studied during the I968, I969 and I970 breeding seasons at Año Nuevo Island, I9 miles north of Santa Cruz, California. Copulation takes place primarily on land, from January to March; it is initiated and terminated by the male and lasts approximately 5 minutes. A few males do most of the breeding and the higher a male's rank in the social hierarchy, the more frequently he copulates. Some bulls may maintain high rank and participate in mating for 3 breeding seasons. Low ranking males are kept out of the harem so they attempt to copulate with females on the periphery or in the water with departing females. Males prevent subordinates from mounting females and disrupt copulations in progress. The higher a male's rank, the more freedom he has to copulate without interference, and the more frequently he interferes with the copulation of others. The highest ranking males interrupt their own copulations prematurely to attack other males and prevent them from copulating. Males mount weaned pups, yearlings, and non-estrous females in addition to estrous females; the latter are mounted most frequently. Females come into estrus 24 days after parturition. They are receptive for about 3 days (range I-I3 days), during which they may copulate several different times with one or more males. Females are usually in estrus when they leave the rookery and return to sea. The greatest difference in the copulatory pattern of the elephant seal, a true seal, and members of the sea lion family, is that the former interfere with the copulations of other males while the latter do not. This may he due to differing social systems, a social hierarchy in elephant seals and a territorial system in sea lions. In elephant seals, where copulations are interrupted, mating may be incomplete. This is not as likely with sea lions where copulations are never interrupted because males honor the boundaries of their neighbors. The differences in female behavior and sexual physiology - a long promiscuous estrous period in elephant seals as opposed to a brief estrus with only one copulation in sea lions - may have evolved as a compensation for the consequences of the social behavior of males.

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