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Polygyny in a wild wolf pack
This is the first recorded case of a single free-ranging male wolf breeding two females. The male settled with one at a den. Both females produced pups, and there is some evidence that the pups survived their first winter despite the male's being killed in summer.
Sowerby's beaked whale ( Mesoplodon bidens ) in the Gulf of Mexico
No abstract available.
A field comparison of nested grid and trapping web density estimators
The usefulness of capture-recapture estimators in any field study will depend largely on underlying model assumptions and on how closely these assumptions approximate the actual field situation. Evaluation of estimator performance under real-world field conditions is often a difficult matter, although several approaches are possible. Perhaps the best approach involves use of the estimation method on a population with known parameters.
Encephalization quotients and life-history traits in the Sirenia
Relative brain size in the Sirenia is unusually small. Encephalization quotients are 0.27 for Florida manatees ( Trichechus manatus ) and 0.38 for dugongs ( Dugong dugon ). Estimates for Steller's sea cow ( Hydrodamalis gigas ) range from 0.12 to 0.19. These values are among the lowest known for Recent mammals, and seemingly have changed little since the Eocene. A body plan specialized for the aquatic environment does not account for low encephalization quotients; values are substantially less than predicted based on cetacean or pinniped allometry. Life-history, ecological, and behavioral traits of the Sirenia are typical of relatively large-brained species. Low quality food and a low metabolic rate, however, are characteristic of the Sirenia and other small-brained mammals. Acting through prolonged postnatal growth, selection also likely favored large body size in the Sirenia without a correlated increase in brain size.
Relationship between age and mass among female white-tailed deer during winter and spring
No abstract available.
Weights, productivity, and mortality of old white-tailed deer
No abstract available.
Geographic distribution of Molossops neglectus Williams and Genoways (Chiroptera: Molossidae)
No abstract available.
Intraspecific mitochondrial DNA variation in North American cervids
Intraspecific variation in mitochondrial DNA of North American cervids was assessed with restriction enzymes to determine relationships among populations and subspecies. No variation was detected in moose ( Alces alces ) and little in elk ( Cervus elaphus ). Caribou ( Rangifer tarandus ), white-tailed deer ( Odocoileus virginianus ), and mule deer ( Odocoileus hemionus ) possessed considerable variation. Characteristic genotypes exist in caribou and white-tailed deer from different geographic areas although subspecies are not discernable as distinct mtDNA assemblages. Except for O. hemionus , intraspecific mtDNA sequence divergences are small (<2%). Subspecies of mule deer have divergent mtDNA (7%) and are the only subspecies of cervids with distinct genotypes.
[Book review] Techniques for Wildlife Investigations: Design and Analysis of Capture Data, by J. R. Skalski and D. S. Robson
No abstract available.
Survival of white-tailed deer fawns in relation to maternal age
No abstract available.
Geographic variation in sea otters, Enhydra lutris
Univariate and multivariate analyses of 20 skull characters of 304 adult sea otters from throughout the geographic range strongly suggest that three subspecies should be recognized. The nominate form, Enhydra lutris lutris , occurs from the Kuril Islands north to the Commander Islands in the western Pacific Ocean. Individuals of E. l. lutris are characterized by large size and wide skulls with short nasal bones. E. l. nereis is found along the California coast and off San Nicolas Island, where the species recently has been reintroduced from coastal California. Specimens of E. l. nereis have narrow skulls with a long rostrum and small teeth, and usually lack the characteristic notch in the postorbital region found in most specimens of the other two subspecies. A new subspecies described by Don E. Wilson in this report, occurs throughout the Aleutian Islands and southward in the eastern Pacific to Washington. Specimens of the new subspecies are intermediate in size in most, but not all, characters and have longer mandibles than either of the other two subspecies.
Effects of maternal and grandmaternal nutrition on deer mass and vulnerability to wolf predation
In a Minnesota ecosystem, mass of female white-tailed deer ( Odocoileus virginianus ) fawns and adults, and survival of adult females in the face of wolf ( Canis lupus ) predation, were directly related to maternal nutrition during gestation. Mass of single male fawns produced by 2-year-old females, and survival of yearlings to 2 years of age were related directly to the nutrition of their grandmothers.
Daytime activity of wolves during winter in northeastern Minnesota
Intermittent aerial observations of 405 radiocollared wolves from November 1968 through March 1989 showed the following percentages of activity: sleeping, 34%; resting, 31%; traveling, 28%, feeding, 6%; other, 2%.
Cannibalism and predation on black bears by grizzly bears in the Yellowstone ecosystem, 1975-1990
We documented one instance of an adult male grizzly bear preying upon a black bear and four instances where circumstantial evidence suggested that grizzly bears (two cubs-of-the-year, one yearling female that was injured, and one adult male) had been preyed upon by conspecifics. We also examined feces of grizzly bears for bear remains. Remains of bears tended to be more common in spring feces and did not differ in frequency between early and late years of the study. Our observations generally support existing hypotheses concerning cannibalism among bears.
Search path of a fossorial herbivore, Geomys bursarius , foraging in structurally complex plant communities
The influence of habitat patchiness and unpalatable plants on the search path of the plains pocket gopher ( Geomys bursarius ) was examined in outdoor enclosures. Separate experiments were used to evaluate how individual animals explored (by tunnel excavation) enclosures free of plants except for one or more dense patches of a palatable plant ( Daucus carota ), a dense patch of an unpalatable species ( Pastinaca sativa ) containing a few palatable plants ( D. carota ), or a relatively sparse mixture of palatable ( D. carota ) and unpalatable ( Raphanus sativus ) species. Only two of eight individuals tested showed the predicted pattern of concentrating search effort in patches of palatable plants. The maintenance of relatively high levels of effort in less profitable sites may reflect the security afforded food resources by the solitary social system and fossorial lifestyle of G. bursarius . Unpalatable plants repelled animals under some conditions, but search paths in the sparsely planted mixed-species treatment suggest animals can use visual or other cues to orient excavations. Evidence supporting area-restricted search was weak. More information about the use of visual cues by G. bursarius and the influence of experience on individual search mode is needed for refining current models of foraging behavior in this species.