Optic nerve, superior colliculus, visual thalamus, and primary visual cortex of the northern elephant seal ( Mirounga angustirostris ) and California sea lion ( Zalophus californianus )

2017 ◽  
Vol 525 (9) ◽  
pp. 2109-2132 ◽  
Author(s):  
Emily C. Turner ◽  
Eva K. Sawyer ◽  
Jon H. Kaas
Keyword(s):  
Visual Cortex ◽  
Optic Nerve ◽  
Primary Visual Cortex ◽  
Elephant Seal ◽  
Zalophus Californianus ◽  
Mirounga Angustirostris ◽  
Sea Lion ◽  
Northern Elephant Seal ◽  
California Sea Lion ◽  
Visual Thalamus

URATE NEPHROLITHIASIS IN A NORTHERN ELEPHANT SEAL (MIROUNGA ANGUSTIROSTRIS) AND A CALIFORNIA SEA LION (ZALOPHUS CALIFORNIANUS)

2007 ◽  
Vol 38 (1) ◽  
pp. 114-120 ◽  
Author(s):  
Sophie Dennison ◽  
Frances Gulland ◽  
Martin Haulena ◽  
Helio De Morais ◽  
Kathleen Colegrove
Keyword(s):  
Elephant Seal ◽  
Zalophus Californianus ◽  
Mirounga Angustirostris ◽  
Sea Lion ◽  
Northern Elephant Seal ◽  
California Sea Lion

Pupillometry in seals and sea lions: ecological implications

1997 ◽  
Vol 75 (12) ◽  
pp. 2050-2057 ◽  
Author(s):  
David Hendrik Levenson ◽  
Ronald J. Schusterman
Keyword(s):  
Sensory Modality ◽  
Maximum Size ◽  
Harbor Seal ◽  
Elephant Seal ◽  
Mirounga Angustirostris ◽  
Sea Lion ◽  
Northern Elephant Seal ◽  
California Sea Lion ◽  
Sea Lions ◽  
Light Levels

Phocid and otariid pinnipeds forage almost exclusively under water, where observing them is difficult. As a result, little is known of how their senses are used while diving to locate and capture prey. In this study we used pupillometric methods to describe the relative visual abilities of three pinniped species: the northern elephant seal (Mirounga angustirostris), the harbor seal (Phoca vitulina), and the California sea lion (Zalophus californianus). The range of pupillary area and lower limit of pupillary adjustment were determined for each species. The northern elephant seal exhibited the largest range of pupillary area of the species examined. Furthermore, the elephant seal's pupil was found to reach maximum size only under extremely dim conditions. Both the harbor seal and California sea lion exhibited maximum pupillary dilation in conditions several log units brighter. These results indicate that the elephant seal's visual system is designed to function in dimmer conditions and to respond to greater changes in light levels than those of the harbor seal and sea lion. Such findings support the hypothesis that the visual systems of these pinnipeds are adapted for use in their respective foraging environments, and thus suggest that the visual sense is probably an important sensory modality used to locate and capture prey while diving.

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 In-air hearing in Hawaiian monk seals: implications for understanding the auditory biology of Monachinae seals

2021 ◽  
Author(s):  
Brandi Ruscher ◽  
Jillian M. Sills ◽  
Beau P. Richter ◽  
Colleen Reichmuth
Keyword(s):  
Marine Mammals ◽  
Elephant Seal ◽  
Critical Ratio ◽  
Mirounga Angustirostris ◽  
Northern Elephant Seal ◽  
Hearing Ability ◽  
Highly Sensitive ◽  
Monk Seals ◽  
Management And Conservation ◽  
Hearing Abilities

AbstractThe auditory biology of Monachinae seals is poorly understood. Limited audiometric data and certain anatomical features suggest that these seals may have reduced sensitivity to airborne sounds compared to related species. Here, we describe the in-air hearing abilities of a Hawaiian monk seal (Neomonachus schauinslandi) trained to participate in a psychophysical paradigm. We report absolute (unmasked) thresholds for narrowband signals measured in quiet conditions across the range of hearing and masked thresholds measured in the presence of octave-band noise at two frequencies. The behavioral audiogram indicates a functional hearing range from 0.1 to 33 kHz and poor sensitivity, with detection thresholds above 40 dB re 20 µPa. Critical ratio measurements are elevated compared to those of other seals. The apparently reduced terrestrial hearing ability of this individual—considered with available auditory data for a northern elephant seal (Mirounga angustirostris)—suggests that hearing in Monachinae seals differs from that of the highly sensitive Phocinae seals. Exploration of phylogenetic relationships and anatomical traits support this claim. This work advances understanding of the evolution of hearing in amphibious marine mammals and provides updated information that can be used for management and conservation of endangered Hawaiian monk seals.

Onset, growth, and recovery of in-air temporary threshold shift in a California sea lion (Zalophus californianus)

2007 ◽  
Vol 122 (5) ◽  
pp. 2916 ◽  
Author(s):  
David Kastak ◽  
Colleen Reichmuth ◽  
Marla M. Holt ◽  
Jason Mulsow ◽  
Brandon L. Southall ◽  
...  
Keyword(s):  
Threshold Shift ◽  
Zalophus Californianus ◽  
Temporary Threshold Shift ◽  
Sea Lion ◽  
California Sea Lion

Dental Pathology of the California Sea Lion (Zalophus californianus)

2014 ◽  
Vol 151 (1) ◽  
pp. 113-121 ◽  
Author(s):  
N.L. Sinai ◽  
R.H. Dadaian ◽  
P.H. Kass ◽  
F.J.M. Verstraete
Keyword(s):  
Zalophus Californianus ◽  
Sea Lion ◽  
California Sea Lion ◽  
Dental Pathology

Quantifying errors associated with using fecal samples to determine the diet of the California sea lion (Zalophus californianus)

2001 ◽  
Vol 79 (6) ◽  
pp. 1080-1087 ◽  
Author(s):  
Anthony J Orr ◽  
James T Harvey
Keyword(s):  
Zalophus Californianus ◽  
Correction Factors ◽  
Sea Lion ◽  
California Sea Lions ◽  
California Sea Lion ◽  
Fecal Samples ◽  
Sea Lions ◽  
Mesh Bag ◽  
Estimate Number ◽  
Fish Otoliths

The purpose of this study was to quantify the errors associated with using fecal samples to determine the diet of the California sea lion (Zalophus californianus). Fishes and squids of known size and number were fed to five sea lions held in enclosures with seawater-filled pools. Enclosures were washed and pools were drained periodically so that sea lion feces could be collected using a 0.5 mm mesh bag. Fish otoliths and squid beaks were collected from feces and used to estimate number and size of prey eaten. An average of 50.7% (SE = 6.4%) of 430 fishes and 73.5% (SE = 12.0%) of 49 cephalopods fed to sea lions were represented by otoliths and beaks in feces, respectively. Estimated lengths of fish from feces were less than lengths of fish fed to sea lions by an average of 30.1% (SE = 2.8%). Beaks were not digested significantly; estimated lengths of squid were underestimated by an average of only 3.3% (SE = 1.5%) relative to actual lengths. Passage rates of otoliths varied, but more than 70% were recovered within 48 h after the fish was consumed. Passage rates of beaks were generally less than those of otoliths; six beaks (11%) were collected in feces 4 days after the squid were eaten. Correction factors were created to more reliably estimate the number and size of fishes and cephalopods eaten by California sea lions.

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