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San Miguel sea lion virus fed to mink and pigs.

Mink became infected with San Miguel sea lion virus when fed ground meat from seal carcasses showing vesicular-like lesions in the skin. The mink also contracted the infection when they were fed San Miguel sea lion virus infected pig meat or cell culture propagated virus. San Miguel sea lion virus infection in mink was inapparent but the virus was isolated from blood and rectal swabs. Pigs treated similarly with the same virus preparations given to mink developed a severe vesicular disease syndrome similar to that produced by vesicular exanthema of swine. In a separate trial, pigs fed a large sample of commercial ground seal meat did not develop disease signs or antibodies. Further work is needed to assess the hazard of introducing San Miguel sea lion virus into swine on the same premises when potentially San Miguel sea lion virus infective seal meat is fed to mink.

Animal Feed

Arteriovenous anastomoses in the skin of seals. II. The California sea lion Zalophus californianus and the northern fur seal Callorhinus ursinus (Pinnipedia: Otariidae).

The structure, distribution and density of arteriovenous anastomoses (AVAs) were studied in body and flipper skin of a California sea lion and a nothern fur seal. In both animals AVAs consisted of arterial, intermediate and venous segments, and were generally larger and more tortuous in the sea lion than in the fur seal. In the sea lion the majority of AVAs (72%) occurred in the deeper region of the dermis, and the density was significantly greater in the flippers than in the body. In the northern fur seal most AVAs (76%) occurred in the superficial region of the dermis; the density of AVAs in flipper skin was significantly higher than in body skin, and the density in the hind flipper was significantly greater than in the foreflipper. Arteriovenous anastomoses are important in the regulation of body temperature in seals; when these animals are on land, AVAs function to dissipate body heat, and vascular thermoregulation occurs in the flippers but notover the general body surface. Due to differences in distribution and density, AVAs play a more significant role in thermoregulation in the northern fur seal than in the California sea lion.

Animals

Structural correlates of forelimb function in fur seals and sea lions.

Dissections, manipulation of ligamentary preparations, analysis of limb proportions, and quantitative aspects of forelimb myology are used to correlate forelimb morphology in fur seals and sea lions (sub-family Otariinae) with previously published data as to their locomotor function (English, '76a). Comparisons to structure and function in generalized fissiped carnivores are then used to elucidate locomotor adaptations in fur seals and sea lions. Unique features of forelimb function during swimming in these pinnipeds include the amounts of abduction-adduction and rotary movements used. Modifications of the size, attachments and fasicle architecture of the muscles and the structure and range of possible movement of the joints suggest that in fur seals and sea lions these movements (1) take place about the glenohumeral (shoulder) joints, (2) that the movements are probably finely controlled, and (3) that they contribute to the generation of massive forward thrust via the cooperative activity of muscles capable of generating large amounts of force throughout the range of movement. Recovery movements occur through a similarly large range, and modifications of forelimb anatomy either to minimize or overcome water resistance are noted. The adaptive significance of these modifications is interpreted as allowing fur seals and sea lions to swim at speeds necessary to feed on the fast swimming prey presumably abundant in their adaptive zone.

Animals

Lipids of the anal sac secretions of the red fox, Vulpes vulpes and of the lion, Panthera leo.

Lion anal sac secretion were found to be richer in lipids and to contain more complex less uniform mixtures of lower moleculas weight lipids then the anal sac of the red fox. In the lion, homologous series of 1-alkylglycerols and 2-hydroxy-fatty acids were identified. Phenylacetic, 3-phenylpropionic, and related hydroxylated acids were also observed. Gas-liquid chromatography profiles of fox anal sac secretion lower molecular weight lipids were found to be less variable in their major constituents and to be dominated by relatively few large peaks, mainly (derivatized) fatty acids. Indole was also identified. Free cholesterol, and occasionally, stanols were observed in fox and lion secretions. In the red fox, total cholesterol levels averaged 0.93 mg/g (% free, 56.4), n = 5. Findings are discussed in relation to histological and anatomical similarities and differences between the anal sacs of the lion and the fox and in the context of the role of these secretions in chemical communication.

Anal Sacs

Functional anatomy of the hands of fur seals and sea lions.

Dissections and manipulations of the hands of 14 specimens of four genera of fur seals and sea lions and of generalized fissiped carnivores were used to identify the structural modifications involved in formation of the expanded forelimb paddles characteristic of these pinnipeds. The morphological peculiarities were then correlated with differences in locomotor function, both on land and in the water, on the basis of previously published data, for the purpose of identifying modifications of structure and function which have adaptive vale. Structural differences found in the manus of fur seals and sea lions include: (1) reduction in size of the ulnar side of the carpus and a radial shift in the length-order of the digits, (2) development of musculature in the antebrachial fascia which attaches to the caudal margin of the flipper, (3) orientation of the radial side of the manus dorsal and radial to the rest of the hand, (4) increased range of possible midcarpal movement and in deviational mobility at the first and fifth digits, (5) attachment of forearm musculature onto radial digits and (6) well-developed hypothenar muscles and absence of thenar muscles. Modifications in hand structure are viewed as providing a morphological basis for employment of the hand to advantage during aquatic locomotion while maintaining thrust-producing and potentially energy-conserving capacities during movement on land. As such these differences in structure and function are viewed as adaptations to locomotion in the water and on land which are extensions of locomotor adaptations attributed to modifications of forelimb structure and function associated with the generation of massive aquatic locomotor thrust. The adaptive value of such modifications is interpreted as allowing fur seals and sea lions to swim with speed and thereby capture elusive fast-swimming prey while maintaining a level of terrestrial locomotor ability compatible with their amphibious mode of life.

Animals

Neurologic lesions in young captive lions associated with vitamin A deficiency.

Ataxia and incoordination occurred in 7 lion cubs in a lion park. Postmortem examination of 3 cubs revealed thickened skull bones which compressed the brain and lead to prolapse of the posterior vermis of the cerebellum through the foramen magnum. In 2 of the lions compression of the anterior cervical spinal cord caused marked damage particularly in the dorsal funiculi. In both cubs the central canal of the spinal cord was abnormal being extended laterally. The pathological changes in the bones and the brain together with low liver vitamin A levels lead to a diagnosis of hypovitaminosis A.

Animals

Tiletamine and zolazepam for immobilization of wild lions and leopards.

A 1:1 mixture of tiletamine and zolazepam was used for the immobilization of lions on 26 occasions and of leopards on 22 occasions. There was a significant (P less than 0.001) positive linear relationship between duration of anesthesia and dosage for all animals in which the duration was recorded (n = 36). This response could be divided into 4 separate regressions according to species and sex; lions being more susceptible to the drug than leopards and males more so than females. When dosage was expressed in terms of metabolic weight, the duration of anesthesia depended on the sex of the animal rather than the species, males being anesthetized 15 minutes longer than females for a given dosage. The threshold dosage was higher in leopards than in lions. The amount of time that could be spent working on the animal immobilized by the drug, compared with the total time committed to its induction, anesthesia, and recovery was 35 to 55%, a proportion that is similar to that associated with the use of other irreversible intramuscular anesthetics.

Anesthesia

Premature parturition in the California sea lion.

Twenty percent of the California sea lion pups born on San Miguel Island die due to premature parturition. Specimens collected from premature-partus animals resulted in recovery of a virus, San Miguel Sea Lion Virus, indistinguishable from Vesicular Exanthema of Swine Virus, and Leptospira pomona from some of the premature cows and pups. The age range of 10 females delivering healthy pups in June was 10-14 years. With one exception, the ages in 10 aborting females was 6-8 years. The p,p'-DDE levels of the premature parturient cows' blubber and liver were 7.6 and 4.8 times greater, respectively, than corresponding tissue concentrations in the full-term animals. Polychlorinated biphenyls residues were 4.4 and 3.8 times greater in aborting animals' blubber and liver than in the same tissues of full-term sea lions. Premature-partus females had tissue imbalances of mercury, selenium, cadmium and bromine. Pathology, parasitology, serum enzyme and hormone results are also presented. These data suggest an interrelationship of disease agents and environmental contaminants as the cause of premature parturition.

Abortion, Veterinary

Plasma biochemical values of clinically-normal Australian sea lions (Neophoca cinerea).

Seventeen biochemical constituents were assayed in the blood plasma of clinically-normal Australian sea lions (Neophoca cinerea). The sea lions formed part of a breeding colony which inhabits the southern coast of Kangaroo Island, South Australia. Little variation was found in any of the values obtained from animals of different age and sex. The results were compared with values published for California sea lions (Zalophus californianus), Northern fur seals (Callorhinus ursinus), Harbor seals (Phoca vitulina) and Northern elephant seals (Mirounga angustirostris).

Animals

Characterization of two new serotypes of San Miguel sea lion virus.

Two new virus isolates, one from a California sea lion (Zalophus californianus californianus) and the other from a northern fur seal (Callorhinus ursinus) were partially characterized. Their physicochemical characteristics were similar to those of vesicular exanthema of swine virus (VESV) and San Miguel sea lion virus (SMSV). The virion morphology was in both instances typically calicivirus. On the basis of this and the serum cross-neutralization testing, these isolates were classed as two new types of SMSV and were designated serotypes SMSV-4 and SMSV-5.

Alaska

Isolation of San Miguel Sea Lion Virus from Samples of an animal food product produced from northern fur seal (Callorhinus ursinus) carcasses.

A virus was isolated from California sea lions (Zalophus californianus californianus) and northern fur seals (Callorhinus ursinus) in 1972. It was later named San Miguel sea lion virus (SMSV). State and federal livestock disease control agencies became concerned, because SMSV was found to be indistinguishable from vesicular exanthema of swine virus and to cause (in laboratory trials) clinical signs in swine similar to those produced by vesicular exanthema of swine virus. Ground carcasses of northern fur seals, salvaged after harvesting pelts, are fed to mink on ranches in the United States. Domestic swine are kept on some of these same ranches. Samples withheld from lots of this seal carcass mink food were found to contain SMSV (serotype 5) in titers of 10(6.1) and 10(6.8) tissue culture infective doses.

Animal Feed

Some important parasitic and other diseases of lion, Panthera leo, in the Kruger National Park.

Lions in the Kruger Park have been found affected by a variety of parasitic and other disease conditions, including trichinosis, filariasis, sarcoptic mange, pentastomiasis, echinococcosis, taeniasis, hepatozoonosis, anthrax, babesiosis and rickets. Six of these may be directly or indirectly transmissible to man or are, at least, closely related to human parasites or disease. Nine of these diseases, or closely related conditions, are also known to infect domestic animal species. The opposite may, of course, also be true--man and his domestic animals may, under certain circumstances, transmit certain diseases to lions, presumably sometimes with fatal results.

Animals

Quantifying the control laws governing terminal attack in lions.

Intercepting an evasive, maneuvering target is among the most computationally demanding tasks a predator performs: in the terminal phase of a chase, it must continuously convert sensory information about the target into steering and speed commands, subject to its own biomechanical limits. How terrestrial predators solve this in real time has remained difficult to quantify. Here, we combine drone videography with AI-based markerless pose estimation to reconstruct the kinematics of 67 lion (Panthera leo) attacks on a mechanized lure programmed to move unpredictably. Lion steering is described by a combination of proportional navigation and proportional pursuit, which is a mixed guidance law previously identified only in the aerial pursuit of Harris's hawks (Parabuteo unicinctus), and speed is regulated within a defined kinematic envelope during turns, which declines at close range where the cost of overshooting is greatest. These findings reveal shared guidance principles across aerial and terrestrial pursuit, thus providing a quantitative framework for comparing pursuit strategies across species.

computational ethology

Electrostatic effects in myoglobin. Application of the modified Tanford-Kirkwood theory to myoglobins from horse, California grey whale, harbor seal, and California sea lion.

The modified Tanford-Kirkwood electrostatic theory (Shire et al., 1974a) was applied to ferrimyoglobins from the following animal species: sperm whale (Physeter catodon), horse, California grey whale (Eschrichtius gibbosus), harbor seal (Phoca vitulina), and California sea lion (Zalophus californianus). Computations were made of the overall hydrogen ion titration curves of the proteins, and of pH and ionic strength variations of ionization equilibria for individual groups in the protein, with particular reference to the hemic acid ionization of the iron bound water molecule. Coordinates and static solvent accessibility were estimated in terms of the sperm whale myoglobin structure. Where possible, theoretical results and experimental data are compared. Some comparative features of charge and ionization properties among the various myoglobins are presented.

Amino Acids

Skull malformation and cerebellar herniation in captive African lions.

Thickening of the cranial vault with a resulting cerebellar herniation is described in a series of litters of lion cubs, all with the same parents, one of whom was also very mildly affected. This animal, when mated to his daughter, also produced affected cubs. The aetiology of the condition is discussed and it is considered that vitamin A deficiency may have been less important than has been suggested by other authors.

Animals

Immobilisation of free-ranging Galapagos sea lions (Zalophus californianus wollebaeki).

Nine free-ranging Galápagos sea lions were immobilised for marking, using a combination of ketamine (3 to 5 mg per kg) and xylazine (0.5 to 1.0 mg per kg). The degree of effect depended largely on the animals' behavioural and physiological state before immobilisation (after parturition, high arousal, subject to aggression, etc.) All nine animals survived. Overheating in the immobilised state may quickly result in heart and circulatory failures.

Animals

Serum concentrations of oestradiol and progesterone during the normal oestrous cycle and early pregnancy in the lion (Panthera leo).

During a 6-month study period weekly serum samples demonstrated 9 oestradiol surges above 14 pg/ml (range 19-108 pg/ml) among 3 lionesses isolated from male lions. Intervals between peaks ranged from 3 to 8 weeks. Progesterone surges of more than 17 ng/ml (range 17-282 ng/ml) and lasting for 2-6 weeks were recorded after 7 of the oestradiol peaks. Sexual behaviour correlated well with the oestradiol peaks. Except for cornification following oestradiol peaks, there was no obvious vaginal cytology pattern at other times of the cycle. Pregnancy occurred after a 12-h contact with a male during behavioural oestrus. During gestation (108 days) oestradiol values remained low, while progesterone was elevated to 49 ng/ml within 12 h after mating, reaching a peak of 143 ng/ml at the 4th week, and remaining elevated during the next 2 months.

Animals