scholarly journals The role of California sea lion (Zalophus californianus) hindflippers as aquatic control surfaces for maneuverability

2021 ◽  
Author(s):  
Ariel M. Leahy ◽  
Frank E. Fish ◽  
Sarah J. Kerr ◽  
Jennifer A. Zeligs ◽  
Stephanie Skrovan ◽  
...  
Keyword(s):  
High Performance ◽  
Performance Metrics ◽  
Delta Wing ◽  
Angle Of Attack ◽  
Zalophus Californianus ◽  
Sea Lion ◽  
Sea Lions ◽  
In The Wild ◽  
Control Surfaces

California sea lions (Zalophus californianus) are a highly maneuverable species of marine mammal. During uninterrupted, rectilinear swimming, sea lions oscillate their foreflippers to propel themselves forward without aid from the collapsed hindflippers, which are passively trailed. During maneuvers such as turning and leaping (porpoising), the hindflippers are spread into a delta-wing configuration. There is little information defining the role of otarrid hindflippers as aquatic control surfaces. To examine Z. californianus hindflippers during maneuvering, trained sea lions were video recorded underwater through viewing windows performing porpoising behaviors and banking turns. Porpoising by a trained sea lion was compared to sea lions executing the maneuver in the wild. Anatomical points of reference (ankle and hindflipper tip) were digitized from videos to analyze various performance metrics and define the use of the hindflippers. During a porpoising bout, the hindflippers were considered to generate lift when surfacing with a mean angle of attack of 14.6±6.3°. However, while performing banked 180o turns, the mean angle of attack of the hindflippers was 28.3±7.3°, and greater by another 8-12° for the maximum 20% of cases. The delta-wing morphology of the hindflippers may be advantageous at high angles of attack to prevent stalling during high-performance maneuvers. Lift generated by the delta-shaped hindflippers, in concert with their position far from the center of gravity, would make these appendages effective aquatic control surfaces for executing rapid turning maneuvers.

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.

Homing by released captive California sea lions, Zalophus californianus, following release on distant islands

1985 ◽  
Vol 63 (9) ◽  
pp. 2162-2164 ◽  
Author(s):  
S. H. Ridgway ◽  
C. C. Robison
Keyword(s):  
San Diego ◽  
Zalophus Californianus ◽  
Sea Lion ◽  
California Sea Lions ◽  
San Nicolas Island ◽  
Sea Lions ◽  
San Diego Bay ◽  
East West ◽  
San Clemente Island

Captive male California sea lions were twice flown to offshore breeding islands and released. Three animals returned to their pen in San Diego Bay after discharge on San Clemente Island, about 115 km away. Two of four returned to the same facility from San Nicolas Island, about 240 km away. The fastest sea lion returned in 2 days from San Clemente and in 4 days from San Nicolas. This is the first evidence for such specific east–west navigation by sea lions and suggests that these animals are good navigators.

scholarly journals Persistent Contaminants and Herpesvirus OtHV1 Are Positively Associated With Cancer in Wild California Sea Lions (Zalophus californianus)

2020 ◽  
Vol 7 ◽  
Author(s):  
Frances M. D. Gulland ◽  
Ailsa J. Hall ◽  
Gina M. Ylitalo ◽  
Kathleen M. Colegrove ◽  
Tenaya Norris ◽  
...  
Keyword(s):  
Zalophus Californianus ◽  
Relative Importance ◽  
Ethical Challenges ◽  
Sea Lion ◽  
California Sea Lions ◽  
Contaminant Exposure ◽  
Control Approach ◽  
Sea Lions ◽  
Cancer Occurrence ◽  
Urogenital Carcinoma

The prevalence of cancer in wild California sea lions (Zalophus californianus) is one of the highest amongst mammals, with 18–23% of adult animals examined post-mortem over the past 40 years having urogenital carcinoma. To date, organochlorines, genotype and infection with Otarine herpesvirus-1 (OtHV-1) have been identified in separate studies using distinct animals as associated with this carcinoma. Multi-year studies using large sample sizes to investigate the relative importance of multiple factors on marine mammal health are rare due to logistical and ethical challenges. The objective of this study was to use a case control approach with samples from 394 animals collected over 20 years in a multifactorial analysis to explore the relative importance of distinct factors identified to date as associated with sea lion cancer in the likelihood of sea lion carcinoma. Stepwise regression indicated that the best model to explain carcinoma occurrence included herpesvirus status, contaminant exposure, and blubber depth, but not genotype at a single microsatellite locus, PV11. The odds of carcinoma was 43.57 times higher in sea lions infected with OtHV-1 (95% CI 14.61, 129.96, p < 0.001), and 1.48 times higher for every unit increase in the loge[contaminant concentrations], ng g–1 (an approximate tripling of concentration), in their blubber (95% CI 1.11, 1.97, p < 0.007), after controlling for the effect of blubber depth. These findings demonstrate the importance of contaminant exposure combined with OtHV1 infection, in the potential for cancer occurrence in wild sea lions.

scholarly journals Can Sea Lions’ (Zalophus californianus) Use Mirrors to Locatean Object?

2015 ◽  
Vol 28 ◽  
Author(s):  
Heather M. Hill ◽  
Krista Webber ◽  
Alicia Kemery ◽  
Melissa Garcia ◽  
Stan A. Kuczaj II
Keyword(s):  
Three Dimensional ◽  
Zalophus Californianus ◽  
Sea Lion ◽  
California Sea Lions ◽  
Sea Lions ◽  
Self Recognition ◽  
Novel Objects ◽  
Dimensional Object ◽  
Physical Features ◽  
First Time

Although California sea lions (Zalophus californianus) are capable of forming complex mental concepts, they have failed to demonstrate mirror self-recognition, a skill that requires both a mental representation of one’s physical features and knowledge of a reflective surface. Many non-human species that do not recognize themselves in mirrors can nonetheless learn to use mirror reflections to locate and retrieve objects. A total of 7 sea lions housed at 2 separate facilities were tested on their ability to detect an object using a mirror. The results of a preliminary detection task in which sea lions were reinforced for looking at a mirror to locate an object suggested that 4 sea lions reliably learned to locate an object positioned below a mirror in one of three locations. A follow-up study was conducted to determine if 3 different sea lions could learn the task without training the animals to use the mirrors. Two of the 3 sea lions located a single object in 1 of the 3 locations statistically above chance when the mirrors were added to the task for the first time. With additional mirror exposure, 1 sea lion successfully achieved 100% accuracy in detecting familiar objects placed in 1 of 3 familiar locations. This sea lion also demonstrated her ability to detect an object via a mirror located in a novel, fourth position with 100% accuracy. When two novel objects were tested with four locations, the sea lion again performed well, detecting the objects 87.5%. The results suggest that sea lions have the ability to use mirrors to locate an object with minimal exposure to a mirror, but likely need additional experience with mirrors to efficiently use the properties of these reflective surfaces and understand that the image is a two-dimensional representation of a three-dimensional object.

Heavy Metal and Chlorinated Hydrocarbon Residues in California Sea Lions (Zalophus californianus californianus)

1975 ◽  
Vol 32 (12) ◽  
pp. 2391-2397 ◽  
Author(s):  
Donald R. Buhler ◽  
Robert R. Claeys ◽  
Bruce R. Mate
Keyword(s):  
Heavy Metal ◽  
Total Mercury ◽  
Chlorinated Hydrocarbons ◽  
Zalophus Californianus ◽  
Sea Lion ◽  
California Sea Lions ◽  
Oregon Coast ◽  
Chlorinated Hydrocarbon ◽  
Sea Lions

Samples of various tissues and organs from healthy California sea lions (Zalophus californianus californianus) and sick animals (apparently with leptospirosis) collected along the central Oregon coast in 1970, 1971, and 1973 were analyzed for total mercury, methylmercury, cadmium, and chlorinated hydrocarbons. Maximum mercury concentrations of 74–170 ppm occurred in sea lion liver, but only 1.6–3.7% of this was present as methylmercury. Cadmium was concentrated primarily in the kidney which contained 7.2–12.0 ppm of the metal. Chlorinated hydrocarbon residues in sea lion fat ranged between 253–475 ppm DDE, and 21.2 and 34.1 ppm PCB. Although mercury, cadmium, and chlorinated hydrocarbon residues in some of the sick sea lions were significantly higher than those present in healthy animals, it is not possible to relate these differences to the onset of leptospirosis.

Metabolic response to fasting in 6-week-old Steller sea lion pups (Eumetopias jubatus)

2000 ◽  
Vol 78 (5) ◽  
pp. 890-894 ◽  
Author(s):  
L D Rea ◽  
D AS Rosen ◽  
A W Trites
Keyword(s):  
Metabolic Response ◽  
Blood Chemistry ◽  
Steller Sea Lion ◽  
Metabolic Adaptation ◽  
Eumetopias Jubatus ◽  
Sea Lion ◽  
Sea Lions ◽  
Lipid Catabolism ◽  
In The Wild ◽  
Change In Mean

Four Steller sea lions (Eumetopias jubatus) aged 6 weeks were fasted for 2.5 d to determine how young pups mobilize energy reserves during short periods of fasting similar to those experienced in the wild. At 6 weeks of age, the pups lost 5.1 ± 0.3% of their body mass during 2 d of fasting, with an average daily mass loss of 0.7 ± 0.1 kg·d-1. Plasma blood urea nitrogen (BUN) concentration increased significantly from 3.0 ± 0.1 mM, after an overnight fast, to 4.8 ± 0.5 mM, after 2.5 d of fasting. It is apparent that BUN levels are quickly depressed, since after only an overnight fast, these pups showed BUN levels 2- to 4-fold lower than those measured after the same pups, when 9 months of age, had recently been fed fish. Plasma ketone body (β-HBA) concentrations of the 6-week-old pups increased significantly from 0.32 ± 0.08 to 0.42 ± 0.08 mM between 0.5 and 1.5 d of fasting. There was no significant change in mean plasma concentration beyond 1.5 d, owing to variable individual responses to extended fasting. Plasma β-HBA levels at 9 months of age ranged from 0.07 to 0.18 mM. Six-week-old Steller sea lion pups showed blood chemistry consistent with metabolic adaptation to fasting within 16 h but were unable to sustain a protein-sparing metabolism for a prolonged period. The pups appeared to revert to protein catabolism after only 2.5 d of fasting. This infers a decrease in lipid catabolism that might be due to the depletion of available lipid resources.

scholarly journals THE ROLE OF DOMOIC ACID IN ABORTION AND PREMATURE PARTURITION OF CALIFORNIA SEA LIONS (ZALOPHUS CALIFORNIANUS) ON SAN MIGUEL ISLAND, CALIFORNIA

2009 ◽  
Vol 45 (1) ◽  
pp. 91-108 ◽  
Author(s):  
Tracey Goldstein ◽  
Tanja S. Zabka ◽  
Robert L. DeLong ◽  
Elizabeth A. Wheeler ◽  
Gina Ylitalo ◽  
...  
Keyword(s):  
Domoic Acid ◽  
Zalophus Californianus ◽  
California Sea Lions ◽  
Sea Lions ◽  
San Miguel Island

Effects of Steady Angle of Attack on Nonlinear Flutter of a Delta Wing Plate Model

2000 ◽  
Author(s):  
Deman Tang ◽  
Earl H. Dowell
Keyword(s):  
Limit Cycle ◽  
High Performance ◽  
Delta Wing ◽  
Plate Theory ◽  
Angle Of Attack ◽  
Limit Cycle Oscillation ◽  
Limit Cycle Oscillations ◽  
Plate Model ◽  
Nonlinear Flutter ◽  
Structural Nonlinearity

Abstract Limit cycle oscillations (LCO) have been observed in flight for certain modern high performance aircraft. The nonlinear physical mechanism responsible for the LCO is still in doubt, even to the point of it not yet being determined whether the nonlinearity is principally in the flexible elastic structure of the aircraft or due to the fluid behavior in the surrounding aerodynamic flow field. One observation from flight tests is that by changing the angle of attack of aircraft, the flight velocity at which LCO begins may be raised or lowered and that the amplitude of the LCO may be reduced. It has been suggested that this sensitivity to angle of attack indicates the nonlinearity is in the fluid rather than in the structure. In the present paper we show that such effects of an angle of attack change can be the result of a structural nonlinearity. Specifically an investigation to determine the effects of a steady angle of attack on nonlinear flutter and limit cycle oscillation of a delta wing-plate model in low subsonic flow has been made. A three-dimensional time domain vortex lattice aerodynamic model and a reduced order aerodynamic technique are used and the structure is modeled using von Karman plate theory that allows for geometric strain-displacement nonlinearities in the delta wing structure. The results provide new insights into nonlinear aeroelastic phenomena not previously widely appreciated, i.e. limit cycle oscillations (LCO) for low aspect ratio wings that have a plate-like nonlinear structural behavior. The effects of a steady angle of attack on both the flutter boundary and the LCO are found to be significant. For a small steady angle of attack, α0 ≤ 0.1°, the flutter onset velocity increases, while for larger α0 it decreases. Moreover, as α0 increases, the maximum LCO amplitude decreases substantially. Such effects have been observed by Bunton and Denegri in flight flutter experiments. It is noted that the present theoretical results do not prove that the LCO phenomena observed in flight are due to structural nonlinearities; however, the results of the present analysis are consistent with those observed in flight and do show that a structural nonlinearity can give rise to the observed effects of angle of attack on LCO.

Verminous Pneumonia in the California Sea Lion (Zalophus californianus)

1970 ◽  
Vol 7 (2) ◽  
pp. 89-101 ◽  
Author(s):  
Robert W. Fleischman ◽  
Robert A. Squire
Keyword(s):  
Bronchial Epithelium ◽  
Zalophus Californianus ◽  
Gastric Ulcers ◽  
Sea Lion ◽  
California Sea Lions ◽  
California Sea Lion ◽  
Sea Lions ◽  
Verminous Pneumonia ◽  
Liver Flukes ◽  
Underlying Pathogenesis

Verminous bronchitis and pneumonia due to Parafiaroides decorus infection is described in California sea lions ( Zalapbus californianus). Marked edema and multiple nodules occurred throughout the lungs. Histologically, both intact and degenerate lungworms occurred and the inflammatory response was pleomophic. A hyaline eosinophilic structure occurring beneath the tracheal and bronchial epithelium was morphologically similar to a structure seen in several human pulmonary diseases. Hypersensitivity may have been important in the underlying pathogenesis of This disease. Liver flukes ( Zalophotrema hepaaticum) and gastric ulcers containing nematodes ( Contraceacum osculalum) occurred in several animals.

scholarly journals Common cancer in a wild animal: the California sea lion ( Zalophus californianus ) as an emerging model for carcinogenesis

2015 ◽  
Vol 370 (1673) ◽  
pp. 20140228 ◽  
Author(s):  
Helen M. Browning ◽  
Frances M. D. Gulland ◽  
John A. Hammond ◽  
Kathleen M. Colegrove ◽  
Ailsa J. Hall
Keyword(s):  
Marine Mammals ◽  
Wild Animal ◽  
Zalophus Californianus ◽  
Sea Lion ◽  
California Sea Lions ◽  
California Sea Lion ◽  
Sea Lions ◽  
Terrestrial Mammals ◽  
The Usa ◽  
Urogenital Carcinoma

Naturally occurring cancers in non-laboratory species have great potential in helping to decipher the often complex causes of neoplasia. Wild animal models could add substantially to our understanding of carcinogenesis, particularly of genetic and environmental interactions, but they are currently underutilized. Studying neoplasia in wild animals is difficult and especially challenging in marine mammals owing to their inaccessibility, lack of exposure history, and ethical, logistical and legal limits on experimentation. Despite this, California sea lions ( Zalophus californianus ) offer an opportunity to investigate risk factors for neoplasia development that have implications for terrestrial mammals and humans who share much of their environment and diet. A relatively accessible California sea lion population on the west coast of the USA has a high prevalence of urogenital carcinoma and is regularly sampled during veterinary care in wildlife rehabilitation centres. Collaborative studies have revealed that genotype, persistent organic pollutants and a herpesvirus are all associated with this cancer. This paper reviews research to date on the epidemiology and pathogenesis of urogenital carcinoma in this species, and presents the California sea lion as an important and currently underexploited wild animal model of carcinogenesis.

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