Cone spectral sensitivity in the harbor seal (Phoca vitulina) and implications for color vision

1998 ◽  
Vol 76 (11) ◽  
pp. 2114-2118 ◽  
Author(s):  
Michael A Crognale ◽  
David H Levenson ◽  
Paul J Ponganis ◽  
Jess F Deegan II ◽  
Gerald H Jacobs
Keyword(s):  
Color Vision ◽  
Spectral Sensitivity ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Chromatic Adaptation ◽  
Harbor Seals ◽  
Sensitivity Curve ◽  
Rods And Cones ◽  
Light Levels ◽  
Spectral Sensitivity Curve

The retinas of harbor seals (Phoca vitulina) contain two morphologically distinct photoreceptor types: rods and cones. The spectral properties of the cones have not been previously studied. The spectral sensitivities of the cones of harbor seals were measured using a retinal gross potential technique, flicker photometric electroretinography. We found a cone spectral sensitivity curve with a peak at about 510 nm. The shape of the spectral sensitivity curve remained invariant despite large changes in chromatic adaptation, implying that harbor seals have only a single cone photopigment. This means that harbor seals must lack color vision at photopic light levels. Any color discrimination in this species would have to be based on combined input from rods and cones and thus restricted to mesopic light levels. The spectral sensitivity of the cone pigment in the harbor seal is shifted to shorter wavelengths than those of terrestrial carnivores, consistent with adaptation to the aquatic photic environment.

scholarly journals The Spectral Sensitivities of Single Cells in the Median Ocellus of Limulus

1969 ◽  
Vol 54 (5) ◽  
pp. 636-649 ◽  
Author(s):  
John Nolte ◽  
Joel E. Brown
Keyword(s):  
Visible Light ◽  
Spectral Sensitivity ◽  
Uv Light ◽  
Single Cells ◽  
Chromatic Adaptation ◽  
Sensitivity Curve ◽  
Receptor Cells ◽  
Intracellular Microelectrodes ◽  
Median Ocellus ◽  
Spectral Sensitivity Curve

The spectral sensitivities of single Limulus median ocellus photoreceptors have been determined from records of receptor potentials obtained using intracellular microelectrodes. One class of receptors, called UV cells (ultraviolet cells), depolarizes to near-UV light and is maximally sensitive at 360 nm; a Dartnall template fits the spectral sensitivity curve. A second class of receptors, called visible cells, depolarizes to visible light; the spectral sensitivity curve is fit by a Dartnall template with λmax at 530 nm. Dark-adapted UV cells are about 2 log units more sensitive than dark-adapted visible cells. UV cells respond with a small hyperpolarization to visible light and the spectral sensitivity curve for this hyperpolarization peaks at 525–550 nm. Visible cells respond with a small hyperpolarization to UV light, and the spectral sensitivity curve for this response peaks at 350–375 nm. Rarely, a double-peaked (360 and 530 nm) spectral sensitivity curve is obtained; two photopigments are involved, as revealed by chromatic adaptation experiments. Thus there may be a small third class of receptor cells containing two photopigments.

Cone spectral sensitivity in the harbor seal (Phoca vitulina) and implications for color vision

1998 ◽  
Vol 76 (11) ◽  
pp. 2114-2118 ◽  
Author(s):  
Michael A. Crognale ◽  
David H. Levenson ◽  
Paul J. Ponganis ◽  
Jess F. Deegan II ◽  
Gerald H. Jacobs
Keyword(s):  
Color Vision ◽  
Spectral Sensitivity ◽  
Harbor Seal ◽  
Phoca Vitulina

Hormonal changes and enforced diving in the harbor seal Phoca vitulina. II. Plasma catecholamines

1982 ◽  
Vol 242 (5) ◽  
pp. R528-R532 ◽  
Author(s):  
A. J. Hance ◽  
E. D. Robin ◽  
J. B. Halter ◽  
N. Lewiston ◽  
D. A. Robin ◽  
...  
Keyword(s):  
Recovery Period ◽  
Control Period ◽  
Plasma Catecholamines ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Hormonal Changes ◽  
Inotropic Effects ◽  
Arterial Constriction

Plasma epinephrine and norepinephrine concentrations were measured in five harbor seals, Phoca vitulina, during a control period, during a 6-min dive, and during a 30-min postdiving recovery period. Measurements were performed with and without prior glucose administration. Control epinephrine concentrations [189 +/- 118 (SD) pg/ml] and norepinephrine concentrations (340 +/- 191 pg/ml) were similar to resting values in humans. During diving there are dramatic increases in both epinephrine and norepinephrine concentrations, which returned to control values by 30 min of the postdiving recovery period. A similar pattern was found after glucose infusion. The increased catecholamines were not the primary mechanism responsible for arterial constriction during the dive. Persistent diving bradycardia suggests obliteration of the chronotropic effects of catecholamines during the dive. An unchanged stroke volume suggests obliteration of the inotropic effects of catecholamines during the dive. Catecholamines do not appear to be involved in postdiving hyperglycemia and hyperglucogenemia. Neither the regulatory role of increased catecholamines nor the physiological function of increased catecholamines was apparent from the studies. However, dramatic increases in plasma catecholamines during diving appear to be an important component of the hormonal response to prolonged diving in aquatic mammals.

scholarly journals Morphological characteristics of harbor seal (Phoca vitulina) whiskers and their use in dietary reconstruction using stable isotope ratios

2018 ◽  
Vol 96 (11) ◽  
pp. 1255-1263 ◽  
Author(s):  
Justin Smith ◽  
Shawna Karpovich ◽  
Greg A. Breed ◽  
Diane M. O’Brien
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Whisker Growth ◽  
Morphological Characteristics ◽  
Isotope Ratios ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Dietary Reconstruction ◽  
Whisker Morphology

We investigated whether inferences about harbor seal (Phoca vitulina Linnaeus, 1758) whisker shed status and growth rates based on whisker morphology could improve dietary time series from whisker isotopic profiles. We identified morphometric characteristics of Alaskan harbor seal whiskers, including a smooth root section (SRS) and a bumpy section. The SRS was longer for spring versus fall-collected whiskers and matched the length of fully grown, shed whiskers. Thus, SRS length can differentiate whisker shed and growth status, and we used it to determine the sequence of whisker shedding by cohort in summer-captured harbor seals. The mean interbump length (IBL) correlated with whisker length, potentially providing a proxy for whisker growth rate. We compared carbon isotope ratios (expressed as δ13C values) along the three longest whiskers from 10 harbor seals, using two approaches for converting whisker position to date: (1) a standard growth rate constant based on captive studies and (2) individually adjusted growth rates based on whisker morphology. Intraindividual patterns of whisker δ13C values became more synchronous when expressed by deposition date rather than by position; however, adjusting growth rates based on IBL did not improve synchrony further. These findings suggest that whisker morphology can contribute whisker growth rate and shedding information for dietary reconstruction.

Influence of storms and maternal size on mother–pup separations and fostering in the harbor seal, Phoca vitulina

1992 ◽  
Vol 70 (8) ◽  
pp. 1640-1644 ◽  
Author(s):  
Daryl J. Boness ◽  
Don Bowen ◽  
Sara J. Iverson ◽  
Olav T. Oftedal
Keyword(s):  
Surface Current ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Frequency Of Occurrence ◽  
Lactation Period ◽  
Maternal Size ◽  
Proximate Causes ◽  
Previous Location

Fostering behavior has been documented in a large number of mammals and birds, but its frequency of occurrence and proximate causes are poorly understood in most species. Ten percent of a sample of 76 paint-marked female harbor seals (Phoca vitulina) fostered pups for some portion of the lactation period. Fostering appears to be associated with females having lost their own pup. In a subsample of 30 pairs that were followed closely, 3 of 16 females that lost their pups fostered, but none of 14 females that maintained continuous association with their pups throughout lactation did so. Smaller, and presumably younger, females were significantly more likely to become separated from their pups than were larger, and presumably older, females (73 vs. 33%). A high proportion (68%) of 35 separations observed occurred during the same day as, or within 1 day following, a storm. In 7 of 8 instances where we relocated pups after they were separated from their mothers during a storm, we found them in the direction of the surface current, 4.9 km from their previous location, on average. These data suggest that storms were the primary cause of separation of harbor seal mothers from their pups, and that younger mothers may be more likely to become separated from their pups. As fostering only occurs after a mother has lost her pup, we suggest that fostering, too, may be more likely among younger females.

Phototaktische Reaktion von Asplanchna priodonta bei monochromatischem Reizlicht/Phototactic Reactions of Asplanchna priodonta to Monochromatic Light

1979 ◽  
Vol 34 (1-2) ◽  
pp. 148-152 ◽  
Author(s):  
Horst Hertel
Keyword(s):  
Spectral Sensitivity ◽  
Monochromatic Light ◽  
Rapid Decrease ◽  
Sensitivity Curve ◽  
Test Light ◽  
Asplanchna Priodonta ◽  
Light Stimuli ◽  
Spectral Sensitivity Curve ◽  
The Way

Abstract 1. The spectral sensitivity curve of the positive phototactic reaction of the rotifer Asplanchna priodon ta has a triple peak. The maxima lie at 363 nm, 453 nm and 552 nm.2. In the shortest wavelength tested and in the area of 453 to 594 nm was the precision of the phototactic orientation found to be high. In between lies a minimum at 395 nm, above 594 nm occurs a rapid decrease in phototactic orientation.3. No wavelength specific differences in the way of orientation were found when using dif­ ferent monochromatic test light stimuli. This leads the same mixture of photopigments.

scholarly journals The Electroretinogram of a Diurnal Gecko

1962 ◽  
Vol 45 (6) ◽  
pp. 1145-1161 ◽  
Author(s):  
G. B. Arden ◽  
Katharine Tansley
Keyword(s):  
Spectral Sensitivity ◽  
Stimulus Intensity ◽  
Dark Adaptation ◽  
Chromatic Adaptation ◽  
Flicker Fusion Frequency ◽  
Fusion Frequency ◽  
Flicker Response ◽  
Dark Adaptation Curve ◽  
Flicker Fusion ◽  
Spectral Sensitivity Curve

Using the electroretinogram as the criterion of retinal activity the flicker fusion frequency, course of dark adaptation, and spectral sensitivity of the pure cone retina of the diurnal gecko, Phelsuma inunguis, were investigated. Both the curve relating flicker fusion frequency to stimulus intensity and that relating the amplitude of the flicker response to stimulus intensity showed a break as the intensity was increased. The dark adaptation curve was that typical of cone retinae; there was no break, adaptation was relatively rapid, and there was a total increase of sensitivity of only about 3 log units. The spectral sensitivity curve showed two maxima, a major one at about 560 mµ and another at about 460 mµ. Chromatic adaptation with red and blue lights demonstrated the presence of two independent mechanisms. Although red adaptation could not have had a direct effect on the pigment responsible for the "blue" mechanism the sensitivity of this mechanism was depressed by red adaptation. The possible relationships of the two mechanisms are discussed.

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