Search USGS⌕ Search

SEARCH · Search USGS

Results for “Journal of Mammalogy”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11Linked to original sources
USGS1975

Blood analyses of wolf pups and their ecological and metabolic interpretation

Blood samples were obtained from 32 wolf ( Canis lupus ) pups live-trapped over a three-year period in northern Minnesota. The results of 21 laboratory analyses of hematology and blood chemistry are tabulated and analyzed in terms of study area, age, sex, and year of collection. Mean values are compared to those reported for dogs in the same age group. The numerous differences between dog and wolf pups are interpreted in terms of nutritional levels and dietary composition with the suggestion that the wolves are not achieving their full growth potential. Individual abnormal test results are tabulated and possible interpretations are suggested. Abnormal results were observed in 13 animals including 10 of 11 animals sampled in 1972. The results in the 1972 animals indicated a poorer nutrition. This preponderance of abnormal test results in pups from 1972 is correlated with ecological studies on this wolf population indicating decreased survival. The potential value of such long-term integrated field and laboratory studies for providing a more complete understanding of changes in the dynamics of natural populations in terms of the responses of individual animals is demonstrated.

Minnesota↗
USGS1976

Influence of stimuli from populations of Peromyscus leucopus on maturation of young

The effects of stimuli associated with conspecific laboratory populations on parameters of sexual maturation in Peromyscus leucopus were examined. Beginning at birth, experimental litters were exposed to the constant infusion of urine, feces, and other material from the populations through a metabolism funnel into their cages. As evidenced by age at first vaginal estrus, experimental females matured later than controls. They also had lighter weight reproductive organs. Testis weights were much greater in control than experimental males. These data suggest that stimuli from populations of P. leucopus can inhibit reproductive maturation of conspecifics. In view of the well-documented effects of chemical stimuli on reproductive maturation and function in other rodents, it is suggested that chemical stimuli in the feces, urine, or from other sources mediated the reproductive inhibition observed in this study.

Journal of Mammalogy↗
USGS1978

Insecticides applied to a nursery colony of little brown bats (Myotis lucifugus): Lethal concentrations in brain tissues

Forty-six Myotis lucifugus were collected in May and June 1974 at a nursery colony in Hillsborough County, New Hampshire, that had been sprayed with DDT and chlordane in August and September 1973. When collected, 27 bats were alive, two were convulsing, and 17 were dead. Brains, carcasses, and milk and masticated insects from stomachs were analyzed for organochlorine insecticides and poly-chlorinated biphenyls (PCB's). Concentrations of chemical residues in brains of surviving bats were compared with those of dead and convulsing bats. These comparisons indicated that DDT was the cause of death. Lethal brain concentrations of DDT in adult females averaged 24.52 parts per million (ppm) and suggested that adult M. lucifugus are approximately twice as sensitive to DDT as are adult laboratory rats and mice. Juvenile bats were about 1.5 times more sensitive than adult bats. Large chemical residues were present in milk. We found a statistically significant relationship between declines in carcass residues in lactating females and uterine regression for six of 10 toxicants. Among juveniles, there were corresponding, significant increases (for nine of 10 toxicants) in carcass levels of residues correlated with increasing age (growth of forearm).

New Hampsire↗
USGS1977

Productivity, mortality, and population trends of wolves in northeastern Minnesota

Population parameters, mortality causes, and mechanisms of a population decline were studied in wolves ( Canis lupus lycaon ) from 1968 to 1976 in the Superior National Forest. The main method was aerial radio-tracking of 129 wolves and their packmates. Due to a decline in white-tailed deer ( Odocoileus virginianus ), the wolf population decreased during most of the study. Average annual productivity varied from 1.5 to 3.3 pups per litter, and annual mortality rates from 7 to 65 percent. Malnutrition and intraspecific strife accounted equally for 58 percent of the mortality; human causes accounted for the remainder. As wolf numbers began to decline, pup starvation became apparent, followed by lower pup production, and then by increased intraspecific strife. At higher densities, adult pack wolves were the most secure members of the population, but as the population declined, they became the least secure because of intraspecific strife.

Minnesota↗
USGS1980

Age, sex, reproduction, and spatial organization of lynxes colonizing northeastern Minnesota

From 1972 through 1978, lynxes ( Felis lynx ) emigrating from Canada were studied in northeastern Minnesota. Fourteen individuals were radio-tracked, 8 were ear-tagged, and 49 carcasses were examined. Sex ratios of the samples were equal during the first years of the study, but females predominated later. At least half of the radio-tagged lynxes were killed by humans; no natural mortality was detected. Home range sizes ranged from 51 to 122 km 2 for females and 145 to 243 km 2 for males, up to 10 times the sizes of those reported by other workers. Ranges of females tended to overlap. Males and females appeared to be segregated in the population.

Journal of Mammalogy↗
USGS1979

Undersea topography and distribution of dolphins of the genus Delphinus in the Southern California Bight

Aerial surveys totalling 21,902 km were analyzed in the Southern California Bight. Although the genus Delphinus is easily recognizable from aircraft, the different species are not detectable in these flights. Delphinus occur more frequently in areas of high relief than in areas of low relief. The depth of the water does not appear to influence distribution of Delphinus . The availability of prey species over areas of different relief may be a major factor influencing these distribution patterns. Although the relative frequencies of occurrence of Delphinus within depth and relief classes do not change from one half of the year to the next, the aggregation sizes differ significantly. From May through October, when anchovies are the major component of the diet and are more available as indicated by the live catch fishery records, Delphinus aggregations have a median size of 250. From November to April the median aggregation size is 40.

California↗
USGS1978

A new species of Myotis from the Islas Tres Marias, Nayarit, Mexico, with comments on variation in Myotis nigricans

A new Myotis is described from the Islas Tres Marias, Nayarit, Mexico. the new species is distinct from related taxa n the adjacent Mexican mainland ( M. californicus, M. leibii , and M. carteri ), although most closely related to M. carteri as shown by univariate and canonical variates analyses. An analysis of six groups of M. nigricans from Middle and South America supports the elevation of M. nigricans carteri to specific status, confirms the distinctness of M. nigricus extremus , but fails to substantiate subspecific status for bats from Columbia and Ecuador, recent recognized as M. n. punensis .

Nayarit↗
USGS1981

Spatial variation in transferrin allele frequencies among herds of feral donkeys in Death Valley National Monument, California

Serum proteins were studied to clarify interrelationships of seemingly disjunct herds of feral donkeys ( Equus asinus ) in the mountains of Death Valley National Monument, California. Sera of 162 donkeys from five localities in the Panamint Mountains were examined by starch-gel electrophoresis to assess polymorphic variation in transferrins. Four homozygous and six heterozygous transferrin phenotypes controlled by four codominant, autosomal alleles were identified with Fe 59 autoradiography. Significant interlocality heterogeneity in genotype distribution and allele frequency distribution among herds was demonstrated. The maximum distance between adjacent herds was 52 km and the minimum distance was 14 km. There are no major physical barriers to movements between herds; furthermore, donkeys are highly mobile animals capable of extensive travel. Behavioral isolation of adjacent herds occurs from May through July, during the peak of reproduction. This isolation is reinforced by fidelity of individuals to their respective home ranges, and to physiological dependence on permanent sources of water. Adjacent herds may overlap during winter when breeding and dependence on water sources are reduced.

Journal of Mammalogy↗
USGS1983

Estimation methodology in contemporary small mammal capture-recapture studies

Estimators of population size and survival rate based on the Jolly-Seber capture-recapture model and the “enumeration method” are described. Enumeration estimators are shown to estimate complicated functions of capture and survival probabilities and, in the case of the population size estimator, population size. Frequently-listed reasons for preferring enumeration estimators are discussed and the Jolly-Seber estimators are shown to be superior even in the case of heterogeneity and trap-happy response, the two sources of unequal capture probability most likely to occur in small mammal studies. New developments in probabilistic capture-recapture models are described, and these models are recommended for future small mammal capture-recapture studies.

Journal of Mammalogy↗