| [the formation in the northern fur seal (callorhinus ursinus l.) of flexible behavioral programs determined by the structure of the complex visual stimulus]. | in callorhinus ursinus l. generalized rule was elaborated of perception of two-stimuli complex visual stimulus (cvs) presented in random and formed from a set of three differentiated stimuli. the animal was trained to perceive the visual information in linear sequence according to the rule of "reading" from top to bottom and make in conformity with this rule labile two-link visual-motor chains of actions signalled by cvs stimuli. such behavioural strategies were called by authors ability to oper ... | 2006 | 2750283 |
| [topical organization of somatic projections to the cerebral cortex of the seal callorhinus ursius]. | somatotopic projections in the cerebral cortex of the fur seal (callorhinus ursinus) were determined by microelectrode recordings of the multiple unit activity. somatosensory cortical area is restricted rostrally by postcruciate and coronal sulci, caudally by anterior suprasylvain sulcus and dorsomedially by ansate sulcus. the somatotopic map in this area is oriented in such a way that the head projection is positioned ventrolaterally and that of the hindlimb dorsomedially. the projection area o ... | 1985 | 4022183 |
| [sleep and wakefulness in callorhinus ursinus]. | sleep and wakefulness of northern fur seals were studied on three subadult bulls carrying the implanted electrodes for recording the electrocorticogram of the two hemispheres, the neck electromiogram, the electrooculogram and the electrocardiogram. the active wakefulness accounted for 32.0 +/- 5.3% of total recording time, the relaxed wakefulness -31.7 +/- 3.1%, the slow wave sleep -30.5 +/- 5.1% and the paradoxical sleep -5.8 +/- 0.9%. the sleep cycle averaged 22,6 +/- 1.2 minutes. interhemisph ... | 2006 | 6475297 |
| clinical observations on three northern fur seal pups treated with dichlorvos. | | 1981 | 7328022 |
| some temperature responses of northern fur seal (callorhinus ursinus) pups. | | 1977 | 908896 |
| lymphosarcoma in an infant northern fur seal (callorhinus ursinus). | an infant northern fur seal (callhorinus ursinus) died in a rookery on st. paul island, pribilof islands, alaska. grossly, slight enlargement of the mesenteric lymph nodes was seen. microscopically, a lymphosarcoma composed of sheets of monomorphic lymphoid cells in sections of lymph node and tonsil was seen. electron microscopy of formalin-fixed tissues revealed several structures that were possible of viral origin in the cytoplasm of the neoplastic cells. | 1977 | 577218 |
| hair mercury concentrations in the spotted seal (phoca largha) pups from the sea of japan. | this publication presents the results of a study of the total mercury (thg) concentration in the fetal hair (lanugo) of the young spotted seals inhabiting the peter the great bay, sea of japan. we analyzed samples from pups that were collected in 2014-2017 at the seal breeding grounds. the concentration of total mercury was determined by atomic absorption spectrometry. the concentration of thg ranged from 1.52 to 6.68 μg/g dry weight. mercury concentration in the lanugo exceeds that found in the ... | 2018 | 30022391 |
| occurrence of pox in a northern fur seal on the pribilof islands in 1951. | the presence of pox in a northern fur seal pup, callorhinus ursinus, examined at necropsy on the pribilof islands, alaska, 13 september 1951 was confirmed by re-examination of formalin-fixed tissues collected at that time. the disease was characterized by multiple 3 to 8 mm modules in the skin of the nose and flippers. unlike pox lesions in other pinnipeds studied so far, the nodules were discrete dermal epitheliomas free of any direct connections with the overlying atrophic epidermis. they most ... | 1980 | 6253687 |
| populations, microhabitat preference and effects of infestation of two species of orthohalarachne (halarachnidae: acarina) in the northern fur seal. | all of 116 northern fur seals examined, except black pups (up to 3 monts old), had nasal mites, orthohalarachne attenuata and o. diminuata, with the mean density of 1,808 mites per subadult male, 435 per adult female, 251 per silver pup, and 21.5 per black pup. only 63% of black pups examined were infested with both mites. larvae represented as much as 99% of the total mite population (total samples), and the females of both species of orthohalarachne accounted for more than 90% of the total pop ... | 1980 | 7373723 |
| fatty acid content of depot fat in the northern fur seal (callorhinus ursinus). | the fatty acid content of depot fat samples from 15 northern fur seals (callorhinus ursinus) were determined by gas-liquid chromatography. callorhinus ursinus has a high proportion of short chain saturated acids: c10, c11, c12, c13, c15. unsaturated longer chain acids c16:1, and c16:2, and c18:1 also were found. results obtained are compared to a previously reported milk lipid analysis of the northern fur seal. | 1979 | 522229 |
| newborn northern fur seals (callorhinus ursinus)--do they suffer from cold? | several hundred thousand northern fur seals (c. ursinus) are born each summer during july at st. paul island in the bering sea. the weather in the area is usually cold, wet, and windy during the breeding season. at birth the pups are small (5--6 kg) and insulated only by a partly wettable pelt and a 2- to 4-mm layer of blubber. in air, the pups' lower critical temperature appears to be below the 6 degrees c 50-yr record low july temperature for the islands. during rainy weather much of the insul ... | 1979 | 443411 |
| prevalence of algal toxins in alaskan marine mammals foraging in a changing arctic and subarctic environment. | current climate trends resulting in rapid declines in sea ice and increasing water temperatures are likely to expand the northern geographic range and duration of favorable conditions for harmful algal blooms (habs), making algal toxins a growing concern in alaskan marine food webs. two of the most common hab toxins along the west coast of north america are the neurotoxins domoic acid (da) and saxitoxin (stx). over the last 20 years, da toxicosis has caused significant illness and mortality in m ... | 2016 | 28073526 |
| psychophysical and electrophysiological aerial audiograms of a steller sea lion (eumetopias jubatus). | a within-subject comparison of auditory steady-state response (assr) and psychophysical measurements of aerial hearing sensitivity was conducted with an individual of the largest otariid species, the steller sea lion. psychophysical methods were used to obtain an unmasked aerial audiogram at 13 frequencies, spanning a range of 0.125-34 khz. the subject had a hearing range (frequencies audible at 60 db(rms) re 20 micropa) of about 0.250-30 khz, and a region of best hearing sensitivity from 5-14.1 ... | 2010 | 20370049 |
| activity-specific metabolic rates for diving, transiting, and resting at sea can be estimated from time-activity budgets in free-ranging marine mammals. | time and energy are the two most important currencies in animal bioenergetics. how much time animals spend engaged in different activities with specific energetic costs ultimately defines their likelihood of surviving and successfully reproducing. however, it is extremely difficult to determine the energetic costs of independent activities for free-ranging animals. in this study, we developed a new method to calculate activity-specific metabolic rates, and applied it to female fur seals. we atta ... | 2017 | 28479996 |
| normal hematology and serum chemistry of northern fur seals (callorhinus ursinus) in captivity. | northern fur seals (callorhinus ursinus) are endemic to the north pacific ocean. they were hunted for their fur and became endangered in the late 1800s, but their populations recovered following the introduction of protection laws. recently, populations have been decreasing again, although the reasons are unclear. for individuals that are bred and reared in captivity as part of ex situ conservation projects, details of blood characteristics are essential to ensure good health. however, the norma ... | 2017 | 28906018 |
| sleep in the northern fur seal. | the pattern of sleep in the fur seal, a semiaquatic pinniped, has several striking behavioral and physiological adaptations that allow this species to inhabit both the land and water environment. these features include unihemispheric slow wave sleep (usws, also being unihemispheric waking), the ability to maintain movement for stabilization of the sleep posture and to briefly open one eye while having a sleep electroencephalogram (eeg) in one hemisphere. in vivo microdialysis studies suggest tha ... | 2017 | 28505502 |
| udp-glucuronosyltransferase (ugt) 2b subfamily interspecies differences in carnivores. | udp-glucuronosyltransferases (ugts) are among the most important xenobiotic metabolizing enzymes that conjugate a wide range of chemicals. previous studies showed that felidae and pinnipedia species have very low ugt activities toward some phenolic compounds because of the ugt1a6 pseudogene and small numbers of ugt1a isozymes. in addition to the ugt1as, ugt2bs isozymes also conjugate various endogenous (e.g., estrogens, androgens, and bile acids) and exogenous compounds (opioids, nsaids, and env ... | 2017 | 28453659 |
| two bacterial genera, sodalis and rickettsia, associated with the seal louse proechinophthirus fluctus (phthiraptera: anoplura). | roughly 10% to 15% of insect species host heritable symbiotic bacteria known as endosymbionts. the lice parasitizing mammals rely on endosymbionts to provide essential vitamins absent in their blood meals. here, we describe two bacterial associates from a louse, proechinophthirus fluctus, which is an obligate ectoparasite of a marine mammal. one of these is a heritable endosymbiont that is not closely related to endosymbionts of other mammalian lice. rather, it is more closely related to endosym ... | 2016 | 26994086 |
| evaluation of the ability of northern fur seals to perceive and visually discriminate images under the conditions of sleep loss. | this is the first study estimating the ability of sea mammals to perceive and analyze information under the conditions of an almost complete sleep deprivation. | 2015 | 26335972 |
| growth of the eye lens: i. weight accumulation in multiple species. | to examine the accumulation of wet and/or dry weight in the ocular lens as a function of age in different species. | 2014 | 24715758 |
| relationship between sleep and eye state in cetaceans and pinnipeds. | we recorded eeg from both hemispheres and documented the state of the two eyes in two species of cetaceans (one beluga and one bottlenose dolphin) and one species of pinnipeds (two northern fur seals). in the dolphin and beluga we found that episodes of unihemispheric slow wave sleep (usws) were associated with asymmetry in eye state. during usws and asymmetrical sws the eye contralateral to the sleeping hemisphere was mostly closed or in an intermediate state while the eye contralateral to the ... | 2004 | 15493557 |
| holocene changes in the ecology of northern fur seals: insights from stable isotopes and archaeofauna. | the remains of northern fur seals (callorhinus ursinus) are among the most abundant of pinniped elements recovered from mainland coastal archaeological sites in both california and oregon. this is surprising as all contemporary northern fur seals breed exclusively on offshore islands, primarily at high latitudes, and the species is otherwise pelagic. the vulnerability of these animals to human predation suggests that either humans were foraging much further offshore than has been presumed or alt ... | 2001 | 28547080 |
| stable isotope assessment of temporal and geographic differences in feeding ecology of northern fur seals (callorhinus ursinus) and their prey. | we investigated the feeding ecology and foraging location of migrating and nursing northern fur seal (callorhinus ursinus) adult females and migrating juvenile males from the pribilof islands, alaska, using carbon (δ(13)c) and nitrogen (δ(15)n) isotope analysis of fur seal skin and whole potential prey. post-parturient and lactating females had mean δ(15)n values significantly (0.8‰) higher than pregnant, migratory females, and δ(13)c values that were not significantly different. two opportunist ... | 2001 | 28547625 |
| determination of inorganic constituents in marine mammal tissues. | analyses of selected tissues from the alaska marine mammal tissue archival project (ammtap) have provided comprehensive information related to levels of 36 trace elements and methyl-mercury in marine mammal tissues. liver, kidney and muscle tissues from two northern fur seals, four ringed seals and six belukha whales were analyzed. the bulk of the investigated tissues and additional tissues from a total of 65 marine mammals are banked in the ammtap. the results are compared to literature values ... | 1993 | 8272841 |
| prevalence of serum antibodies to coxiella burnetii in alaska native persons from the pribilof islands. | q fever is a febrile illness caused by infection with the bacterium coxiella burnetii. it is most often transmitted by inhalation of the bacteria after it is shed by infected livestock. recent studies have found very high c. burnetii infection rates among marine mammals, but it is not known if shedding by marine mammals creates a risk of q fever among humans. to better understand infection of humans with exposure to marine mammals, the prevalence of antibodies against c. burnetii in serum sample ... | 2020 | 31705592 |
| evaluating exposure of northern fur seals, callorhinus ursinus, to microplastic pollution through fecal analysis. | environmental microplastics are widely documented in marine life and bioaccumulation may present risks to marine predators. investigations of microplastics in marine mammals are increasing, though none have examined animals routinely consumed by humans. here, we investigate microplastic exposure in the northern fur seal (callorhinus ursinus), a species consumed by humans, using fecal material. we examined 44 feces (scat) at sites encompassing the seals' eastern pacific range. multiple contaminat ... | 2019 | 30660265 |
| fur seals suppress rem sleep for very long periods without subsequent rebound. | virtually all land mammals and birds have two sleep states: slow-wave sleep (sws) and rapid eye movement (rem) sleep [1, 2]. after deprivation of rem sleep by repeated awakenings, mammals increase rem sleep time [3], supporting the idea that rem sleep is homeostatically regulated. some evidence suggests that periods of rem sleep deprivation for a week or more cause physiological dysfunction and eventual death [4, 5]. however, separating the effects of rem sleep loss from the stress of repeated a ... | 2018 | 29887309 |
| stress-related and reproductive hormones in hair from three north pacific otariid species: steller sea lions, california sea lions and northern fur seals. | assessing the physiological impact of stressors in pinnipeds is logistically challenging, and many hormones are altered by capture and handling, limiting the utility of metabolically active tissues. hair is increasingly being used to investigate stress-related and reproductive hormones in wildlife populations due to less-invasive collection methods, being metabolically inert once grown and containing multiple biomarkers of ecological interest. we validated enzyme immunoassays for measuring aldos ... | 2020 | 32843968 |
| eye state asymmetry during aquatic unihemispheric slow wave sleep in northern fur seals (callorhinus ursinus). | unihemispheric slow wave sleep (usws) is a unique form of sleep in which one brain hemisphere maintains low voltage electrical activity indicative of waking while the opposite exhibits slow wave electrical activity indicative of sleep. usws is present in several marine mammals and in some species of birds. one proposed biological function of usws is to enable the animal to monitor the environment to detect predators or conspecifics. while asymmetrical eye state was often observed during behavior ... | 2019 | 31116774 |
| dental integration and modularity in pinnipeds. | morphological integration and modularity are important for understanding phenotypic evolution because they constrain variation subjected to selection and enable independent evolution of functional and developmental units. we report dental integration and modularity in representative otariid (eumetopias jubatus, callorhinus ursinus) and phocid (phoca largha, histriophoca fasciata) species of pinnipedia. this is the first study of integration and modularity in a secondarily simplified dentition wi ... | 2019 | 30862801 |
| neuroethology: fur seals don't lose sleep over rem lost at sea. | northern fur seals forego large amounts of rapid eye movement (rem) sleep when sleeping in water, but remain healthy and do not recover this loss once back on land, challenging current theories for the function of rem sleep. | 2018 | 29920262 |
| digeneans of northern fur seals callorhinus ursinus (pinnipedia: otariidae) from five subpopulations on st. paul island, alaska. | a parasitological survey of 651 northern fur seals callorhinus ursinus l. from five subpopulations was conducted on st. paul island, alaska, during july-august 2012-2014. digenean trematodes were found in 210 of 651 fur seals with a total prevalence of 32.3%. intensity of infection varied from 1 to 1540 parasites with mean intensity 18.4 ± 111.1 sd and median intensity of 2 specimens per host. significant differences in prevalence and intensity of infection in northern fur seals between separate ... | 2018 | 29435720 |
| host population expansion and the genetic architecture of the pinniped hookworm uncinaria lucasi. | the long-term fidelity of pinniped hosts to their natal rookery site suggests the genetic architecture of their uncinaria spp. hookworms should be strongly structured by host breeding biology. however, historical events affecting host populations may also shape parasite genetic structure. sequences of the mitochondrial cytochrome c oxidase 1 (coi) gene of 86 uncinaria lucasi individuals were obtained to assess genetic variation and structure of nematodes from 2 host species (68 hookworms from no ... | 2020 | 32491171 |
| links between muscle phenotype and life history: differentiation of myosin heavy chain composition and muscle biochemistry in precocial and altricial pinniped pups. | in marine mammals, muscular development has been identified as a rate-limiting factor in achieving adult dive capacities. this study investigates the rate that myosin heavy chain (mhc) composition matures in a postural and locomotor skeletal muscle for four pinniped species with different lactation lengths: hooded seals, cystophora cristata; harp seals, pagophilus groenlandicus; northern fur seals, callorhinus ursinus, and steller sea lions, eumetopias jubatus. the ontogeny of mhc isoform expres ... | 2019 | 31616978 |
| deciphering the evolutionary signatures of pinnipeds using novel genome sequences: the first genomes of phoca largha, callorhinus ursinus, and eumetopias jubatus. | the pinnipeds, which comprise seals, sea lions, and walruses, are a remarkable group of marine animals with unique adaptations to semi-aquatic life. however, their genomes are poorly characterized. in this study, we sequenced and characterized the genomes of three pinnipeds (phoca largha, callorhinus ursinus, and eumetopias jubatus), focusing on site-wise sequence changes. we detected rapidly evolving genes in pinniped lineages and substitutions unique to pinnipeds associated with amphibious sou ... | 2018 | 30442995 |
| brucella antibodies in alaskan true seals and eared seals-two different stories. | brucella pinnipedialis was first isolated from true seals in 1994 and from eared seals in 2008. although few pathological findings have been associated with infection in true seals, reproductive pathology including abortions, and the isolation of the zoonotic strain type 27 have been documented in eared seals. in this study, a brucella enzyme-linked immunosorbent assay (elisa) and the rose bengal test (rbt) were initially compared for 206 serum samples and a discrepancy between the tests was fou ... | 2018 | 29445729 |
| migratory strategies of juvenile northern fur seals (callorhinus ursinus): bridging the gap between pups and adults. | in species exhibiting differential migration by sex and age, understanding what differences exist, and the adaptive reasons for these differences is critical for determining how demographic groups will respond to environmental variability and anthropogenic perturbations. we used satellite-telemetered movement and diving data to investigate differential migration and its ontogeny in a highly migratory north pacific ocean predator, the northern fur seal (callorhinus ursinus; nfs), with a focus on ... | 2019 | 31558737 |
| pairing ultrasonography with endocrinology to elucidate underlying mechanisms of successful pregnancy in the northern fur seal (callorhinus ursinus). | reproductive success is one of the central tenets of conservation management programs, yet the inability to study underlying physiological processes in a minimally-invasive manner and the unpredictable nature of wild animal populations leaves large gaps in our knowledge of factors critical to successful reproduction in wild species. this study integrated ultrasonography of the reproductive tract and analysis of reproductive hormones in 172 northern fur seals (callorhinus ursinus) to identify int ... | 2018 | 29051074 |
| review of metazoan parasites of the northern fur seal (callorhinus ursinus) and the analysis of the gastrointestinal helminth community of the population on st. paul island, alaska. | the northern fur seal (nfs), callorhinus ursinus (mammalia: otariidae), is a marine mammal species included into the iucn red list as the vulnerable species which population is dramatically declining. a significant amount of parasitological data collected previously and our recent data allowed us to clarify the list of nfs metazoan parasites and to perform a comprehensive analysis of the gastrointestinal helminth community. gastrointestinal tracts from 756 nfss (3- to 4-year-old males) were coll ... | 2020 | 33159458 |
| factors affecting energy expenditure in a declining fur seal population. | quantifying metabolic rates and the factors that influence them is key to wildlife conservation efforts because anthropogenic activities and habitat alteration can disrupt energy balance, which is critical for reproduction and survival. we investigated the effect of diving behaviour, diet and season on field metabolic rates (fmr) and foraging success of lactating northern fur seals (callorhinus ursinus) from the pribilof islands during a period of population decline. variation in at-sea fmr was ... | 2019 | 31890212 |
| entanglement of northern fur seals (callorhinus ursinus) in marine debris on tyuleniy island (sea of okhotsk) in 1998-2013. | the systematic annual observations of the northern fur seal rookery on tyuleniy (= robben) island, sea of okhotsk, were started in 1958. since 1975, all seals entangled in marine debris have been registered. some of the data on this issue, collected on the island in the late 20th century, were published earlier. this report provides data for the period of completion of the commercial sealing (from 1998 to 2013). during this period, a total of 867 fur seals were observed entangled in marine debri ... | 2019 | 31789154 |