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Articles 5371 - 5400 of 5825

Full-Text Articles in Animal Sciences

Reproductive Strategies Of Meadow Voles, Hispid Cotton Rats, And Eastern Harvest Mice In Virginia, Robert K. Rose Jan 1986

Reproductive Strategies Of Meadow Voles, Hispid Cotton Rats, And Eastern Harvest Mice In Virginia, Robert K. Rose

Biological Sciences Faculty Publications

Patterns of reproduction in small mammals in Virginia were examined by autopsying samples of meadow voles (Microtus pennsylvanicus) collected for 23 months near Charlottesville, of hispid cotton rats (Sigmodon hispidus) collected for 14 months in Portsmouth, and by evaluating live-caught eastern harvest mice (Reithrodontomys humulis) trapped for 15 months in Suffolk and for 12 months in Chesapeake. The meadow vole, a microtine rodent with a north temperate and sub-arctic distribution throughout North America, suspended breeding during the winter of peak density but not of declining density. High metabolic rates and other adaptations for winter …


The Hippocampus As Episodic Encoder: Does It Play Tag?, Robert H.I. Dale Sep 1985

The Hippocampus As Episodic Encoder: Does It Play Tag?, Robert H.I. Dale

Scholarship and Professional Work - LAS

Rawlins’s characterization of the hippocampus as a “high-capacity, immediate-term memory store” captures the essential idea in a number of previous models. For example, Gaffan (1974), Gray (1984), Hirsh (1980), Kesner (Bierley, Kesner & Novak 1983), Olton (Olton, Becker & Handelmann 1979), Solomon (1980), and Winocur (1980) all agree that hippocampal animals show memory deficits when required to identify, for whatever reason, one specific event out of a list of recent events. Although these authors disagree on a number of details, Rawlins has identified their models common ground, the core of each model. (It is only fair to note that Gaffan …


The Relationship Between Habitat Structure And Small Mammal Communities In Southeastern Virginia And Northeastern North Carolina, Roger Keith Everton Jul 1985

The Relationship Between Habitat Structure And Small Mammal Communities In Southeastern Virginia And Northeastern North Carolina, Roger Keith Everton

Biological Sciences Theses & Dissertations

A variety of terrestrial habitats was pitfall trapped in the vicinity of the Great Dismal Swamp of eastern Virginia and North Carolina to evaluate the small mammal community within the region. Habitat variables were measured at the end of the growing season on 21 0.25 ha grids. Four multivariate tests were used to examine the small mammal communities, their relationship with habitat structure, and the role of habitat selection in community structure.

Cluster and ordination analysis revealed the existence of two distinct associations of small mammals, and their habitat types, within the region. The small mammal associations were interpreted as …


March Rice Rat, Oryzomys Palustris, Hugh H. Genoways Jan 1985

March Rice Rat, Oryzomys Palustris, Hugh H. Genoways

University of Nebraska State Museum: Mammalogy Papers

Includes information on other names used, description, range, habitat, life history and ecology, basis of classification, and recommendations of/for the march rice rat, Oryzomys palustris, in Pennsylvania, USA.


Badger, Taxidea Taxus, Hugh H. Genoways Jan 1985

Badger, Taxidea Taxus, Hugh H. Genoways

University of Nebraska State Museum: Mammalogy Papers

Includes information on another name, the description, range, habitat, life history and ecology, basis of classification, and recommendations of/for the badger, Taxidea taxus, in Pennsylvania, USA.


Pygmy Shrew, Microsorex Hoyi, Hugh H. Genoways Jan 1985

Pygmy Shrew, Microsorex Hoyi, Hugh H. Genoways

University of Nebraska State Museum: Mammalogy Papers

Includes the description, range, habitat, life history and ecology, basis of classification, and recommendations of/for the pygmy shrew (Microsorex hoyi) in Pennsylvania, USA.


A Survey Of Drench Resistance In Sheep Worms, J R. Edwards, R. Wroth, G. C. De Chaneet, R. B. Besier, J. Karlsson, P. W. Morcombe, D. Roberts, G. Dalton-Morgan Jan 1985

A Survey Of Drench Resistance In Sheep Worms, J R. Edwards, R. Wroth, G. C. De Chaneet, R. B. Besier, J. Karlsson, P. W. Morcombe, D. Roberts, G. Dalton-Morgan

Journal of the Department of Agriculture, Western Australia, Series 4

Sheep worms which are resistant to chemical drenches have been detected with increasing freuency is Western Australia's south-western farming areas between 977 and 1980. These worms have anthelmintic resistance and such genetis resistance puts essential internal parasite control practices at risk.

This prompted veterinarians in the Esperance, Albany, Bunbury, Geraldton and Northam areas to survey farms to determine the prevalence of resistance to drenches and to define those sheep management practices which encourage its development.

This article describes the survey which was conducted to assess the extent of drench resistance, what causes its build-up and how it can be controlled …


The Ecology Of Foraging Behavior: Implications For Animal Learning And Memory, Alan Kamil, Herbert L. Roitblat Jan 1985

The Ecology Of Foraging Behavior: Implications For Animal Learning And Memory, Alan Kamil, Herbert L. Roitblat

Avian Cognition Papers

In his recent Annual Review of Psychology article, Snowdon (1983) discussed the synthesis of ethology and comparative psychology. A similar synthesis of behavioral ecology and animal learning is beginning to take place. This article reviews developments in the behavioral ecology and ethology of foraging behavior relevant to psychological research on animal learning. The psychological literature shows that animals possess a wide range of learning abilities, including “simple” classical and operant conditioning; they acquire spatial, nonspatial, and temporal discriminations; they exhibit various forms of rule learning (e.g. matching-to-sample and learning set), and may even in certain senses learn language. Why does …


Gametogenesis En Chthonerpeton Indistinctum (Gymnophiona: Typhlonectidae), Rafael O. De Sá, Nibia Berois Jan 1985

Gametogenesis En Chthonerpeton Indistinctum (Gymnophiona: Typhlonectidae), Rafael O. De Sá, Nibia Berois

Biology Faculty Publications

RESUMEN:

Histológicamente, las gónadas de Chthonerpeton indistinctum son similares a las ya descritas para otras especies del orden Gymnophiona. Los lóbulos testiculares se hallan compartimentados en unidades estructurales denominadas lóculos. La espermatogénesis ocurre en cistos sincrónicos de células germinales. Durante la espermiogénesis se identifican cuatro estados consecutivos de desarrollo: 1) cistos de espermátidas redondeadas; 2) cistos de espermátidas arrifionadas; 3) cistos de espermátidas bastoniformes y 4) espermátidas en ramillete.

El análisis histológico de los ovarios mostró la presencia de tres estados en la maduración de los folículos ováricos. Estas etapas pueden ser identificadas de acuerdo a: 1) ubicación del folículo …


Estructura Del Ovario De Chthonerpeton Indistinctum (Reinhardt Y Lutken, 1862) (Amphibia: Gymnophiona) Durante La Gestación, Rafael O. De Sá, Nibia Berois Jan 1985

Estructura Del Ovario De Chthonerpeton Indistinctum (Reinhardt Y Lutken, 1862) (Amphibia: Gymnophiona) Durante La Gestación, Rafael O. De Sá, Nibia Berois

Biology Faculty Publications

La morfología e histología del ovario para varias especies del orden Gymnophiona ha sido reportada por Wake (1968, J. Morphol. 126, 291) y para C. indistinctum por los autores (1984, XXIV Reunión de Comunicaciones, Soc. Zool. Uruguay).

Continuando con los estudios sobre el aparato genital de esta especie vivípara, se presenta ahora la estructura del ovario durante la gestación.

Se procesaron con fines histológicos, ovarios de dos hembras grávidas colectadas en las costas de los Dep. Montevideo y San José en abril, 1983. El número de ejemplares trabajados es muy reducido dado lo difícil que resulta su colecta …


Introduction To Species Of Special Concern In Pennsylvania, Chapter 6--Mammals, Hugh H. Genoways Jan 1985

Introduction To Species Of Special Concern In Pennsylvania, Chapter 6--Mammals, Hugh H. Genoways

University of Nebraska State Museum: Mammalogy Papers

First two paragraphs:

The mammals in Pennsylvania have long been under the management authority of the Pennsylvania Game Commission, but it was not until 1978 that an effort was made to deal with threatened and endangered mammals in the Commonwealth. At this time, Michael J. Puglisi was appointed as Coordinator for the Threatened and Endangered Species Program within the Game Commission. In late February 1979, Mr. Puglisi asked Hugh H. Genoways to chair an informal study group on endangered mammals in Pennsylvania. The immediate concern of this group was to be the development of a list of threatened and endangered …


Age And Growth Of The Bluegill Lepomis Macrochrius Rafinesque From An Unmanaged Watershed Lake In Northeast Arkansas With Observations On Lake Ecology, Stephen A. Sewell Jan 1985

Age And Growth Of The Bluegill Lepomis Macrochrius Rafinesque From An Unmanaged Watershed Lake In Northeast Arkansas With Observations On Lake Ecology, Stephen A. Sewell

Journal of the Arkansas Academy of Science

Age and growth data were compiled on 114 bluegill, Lepomis macrochirus Rafinesque, taken from floodwater retarding structure #15 of the Big Creek Watershed project in Craighead and Greene counties of northeast Arkansas. This project was completed in the early 1960's by USDA-SCS. The 73 surface acre lake has not been managed for fish production and has been subjected to unscheduled water level manipulations during dry weather periods. These manipulations have maintained the bluegill population in healthy condition. The oldest bluegill collected were age class IV+. Average condition coefficient K(TL)declined from oldest to youngest individuals (2.96 in age class IV+ - …


Nearshore Foodwebs And The Distribution Of Acanthocephalan Parasites In Antarctic Seabirds, Eric P. Hoberg Jan 1985

Nearshore Foodwebs And The Distribution Of Acanthocephalan Parasites In Antarctic Seabirds, Eric P. Hoberg

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Field studies, in the vicinity of Palmer Station during the austral summer of 1982— 1983, yielded an extensive collection of acanthocephalans and other parasites from seabirds, fish and invertebrates. The continuing analysis of this material has resulted in the elucidation of factors that control the occurrence of Corynosoma spp. in Antarctic seabirds. Notably, the host-distribution of Corynosoma spp. suggested that these parasites were being acquired from piscine or possibly amphipod prey, generally in nearshore habitats.


Community Ecology, Robert K. Rose, Elmer C. Birney Jan 1985

Community Ecology, Robert K. Rose, Elmer C. Birney

Biological Sciences Faculty Publications

COMMUNITIES with Microtus tend to be structurally simple, usually grasslands or tundra, and to have no more than two species of Microtus and rarely more than six species of small mammals. Microtus often dominates both numerically and in total small mammal biomass, especially at higher latitudes. The small mammal community is most influenced by Microtus through its fluctuations in density, and thus also in biomass, by its relatively high level of diurnal activity, and by its year-round activity. Other species of small mammals may be adversely affected because Microtus usually is larger and behaviorally dominant and also because the mere …


A Proposal To Fertilize The Overton Arm And Gregg Basin Areas Of Lake Mead, Larry J. Paulson Nov 1984

A Proposal To Fertilize The Overton Arm And Gregg Basin Areas Of Lake Mead, Larry J. Paulson

Publications (WR)

Several limnological studies have been conducted in Lake Mead during the past decade. The recent studies clearly show that most of Lake Mead is deficient in nutrients, especially phosphorus, and very low in productivity. The reservoir-wide average total phosphorus concentration for 1981 - 1982 was only 9 mg/m3. This is below levels found In most oligotrophic lakes and reservoirs. Algal biomass, as measured by chlorophyll-a, averaged only 1.5 mg/m3. That also places Lake Mead in the oligotrophic range. Transparency, as measured by a Secchi disc, averaged 9-5 m in Lake Mead during 1981-1982. That far exceeds …


Demographic Analysis And Microhabitat Relationships Of A Small Mammal Community In Clearings Of The Great Dismal Swamp, Jean Ferguson Stankavich Oct 1984

Demographic Analysis And Microhabitat Relationships Of A Small Mammal Community In Clearings Of The Great Dismal Swamp, Jean Ferguson Stankavich

Biological Sciences Theses & Dissertations

Small mammals were trapped for 14 months on two grids located within a powerline right-of-way in the Great Dismal Swamp National Wildlife Refuge. During 12,354 trap nights, individuals of 10 different species were captured. They included, from highest to lowest density, Reithrodontomys humulis, Ochrotomys nuttalli, Peromyscus leucopus, Blarina brevicauda, Synaptomys cooperi, Microtus pennsylvanicus, Microtus pinetorum, Sigmodon hispidus, Mus musculus and Oryzomys palustris. The demography (densities, reproduction, home range and dispersal) of each species was analyzed when possible. Most of the species were present in relatively low densities, with a number being captured only during the latter months of the study. …


Catalog Of The Recent Scandentia And Primates In The Carnegie Museum Of Natural History, Suzanne B. Mclaren, Duane A. Schlitter, Hugh H. Genoways Sep 1984

Catalog Of The Recent Scandentia And Primates In The Carnegie Museum Of Natural History, Suzanne B. Mclaren, Duane A. Schlitter, Hugh H. Genoways

University of Nebraska State Museum: Mammalogy Papers

The Section of Mammals, Carnegie Museum of Natural History, houses six specimens of Recent tree shrews and 611 specimens of Recent primates. The only family in the Order Scandentia is Tupaiidae. Primate families represented are Lemuridae, Lorisidae, Cebidae, Callitrichidae, Cercopithecidae, Pongidae, and Hominidae. For each specimen the following data are recorded: locality; date collected; catalog number; sex; age; nature of specimen; condition of specimen and comments. The latter category gives information on the condition of the skin and skeletal material, and gives information on the availability of the specimen.


Results Of The Alcoa Foundation-Suriname Expeditions. Ix. Bats Of The Genus Tonatia (Mammalia: Chiroptera) In Suriname, Hugh H. Genoways, Stephen L. Williams Jul 1984

Results Of The Alcoa Foundation-Suriname Expeditions. Ix. Bats Of The Genus Tonatia (Mammalia: Chiroptera) In Suriname, Hugh H. Genoways, Stephen L. Williams

University of Nebraska State Museum: Mammalogy Papers

Five species of Tonatia (bidens, brasilense, carrikeri, schulzi, and silvicola) are known to occur in Suriname. Tonatia bidens and silvicola are the largest in overall size (forearm length over 50 mm and greatest length of skull over 27.0 mm). However, T. bidens has a broader postorbital region (5.0 mm or more) and narrower mastoid region (less than 13.0 mm). The lower incisors of T. bidens are also noticeably broader than those of T. silvicola. These two species were found throughout most of the forested areas of Suriname. T. bidens displayed no secondary sexual …


Life History Aspects Of Reithrodontomys Humulis In Southeastern Virginia, Michelle Cawthorn Chandler Jul 1984

Life History Aspects Of Reithrodontomys Humulis In Southeastern Virginia, Michelle Cawthorn Chandler

Biological Sciences Theses & Dissertations

Reithrodontomys humulis, the eastern harvest mouse, is a small cricetid rodent which is common in old field communities in the eastern U.S. A live-trapping study was conducted in Suffolk, Virginia from March 1983 through February 1984 in order to learn the details of its life history and the vegetational characteristics which best describe its microhabitat. Specifically, population densities, trap-revealed survival times, home ranges, plant species composition of the study area, and vegetational structure were examined. In order to trap as many Reithrodontomys as possible, special traps which excluded animals weighing over 20 g were constructed. Densities of harvest mice …


Determinants Of Variation In Avian Mobbing Behavior, Charles Ray Chandler Jr. Jul 1984

Determinants Of Variation In Avian Mobbing Behavior, Charles Ray Chandler Jr.

Biological Sciences Theses & Dissertations

Using three combinations of two experimental stimuli, I initiated mobbing behavior in various species of birds. The objectives of this research were to test the effects of stimuli on mobbing, the predictions of the hypothesis that mobbing functions to drive a predator away, and the effect of other species and individuals on the mobbing behavior of a bird. Mobbing experiments were conducted in a variety of habitats and locations from January 1983 through February 1984.

Only 6.5% of all trials with the mount-only stimulus were successful in attracting birds. Tape-only and mount-and-tape stimuli were equally effective in attracting birds, but …


Activity Levels Of Arboreal Rodents Peromysus And Ochrotomys Evaluated With Nest Cans In Seasonally Flooded Forests, John W. Walke Jul 1984

Activity Levels Of Arboreal Rodents Peromysus And Ochrotomys Evaluated With Nest Cans In Seasonally Flooded Forests, John W. Walke

Biological Sciences Theses & Dissertations

The diversity and density of small mammals in the Dismal Swamp are believed to be small. To test this, four 1.96 ha grids were established and operated in the Dismal Swamp National Wildlife Refuge, from September 1981 to November 1982. Number 10 metal cans covered with plastic lids were placed as nest boxes at 0.5 to 1.5 m height on trees. A 2.5 cm hole allowed access by arboreal rodents, to each nest can. The activity level of the two arboreal rodents, Peromyscus leucopus and Ochrotomys nuttalli, was evaluated by observing types of activity ranging from presence of mice to …


Seasonal And Spatial Heterogeneity In The Limnetic Zooplankton Community Of Lake Mead, Gene Robert Wilde May 1984

Seasonal And Spatial Heterogeneity In The Limnetic Zooplankton Community Of Lake Mead, Gene Robert Wilde

Publications (WR)

Zooplankton samples collected from throughout Lake Mead, in 1981-1982, demonstrate the presence of a statistically significant seasonal and spatial heterogeneity in zooplankton densities. Seasonally, the major zooplankton groups were most abundant in the spring and fall, coincident with maxima in chlorophyll-a concentrations. Successions among the various rotifers, cladocerans and copepods present in the reservoir were influenced by food availability, diapause, predation by planktivorous fish and, possibly, water temperatures. Spatial heterogeneity in zooplankton densities was unrelated to water temperature, pH, conductivity and dissolved oxygen concentrations, but was related to the abundance of phytoplankton (chlorophyll-a concentrations) and fish. Statistical analyses indicate that …


The Hellbender, Cryptobranchus Alleganiensis, In Indiana, William H. Kern Jr. May 1984

The Hellbender, Cryptobranchus Alleganiensis, In Indiana, William H. Kern Jr.

All-Inclusive List of Electronic Theses and Dissertations

Very 1 ittle was previously known ubout the Hellbender, Crrp:t:£branchus alleganiensis alleganiensis, in Indiana. The purpose of this study was to determine its current range and status in Indiana and collect life history information. The hell benders were captured by hand from under rocks and 1d th hoopnets baited with cut fish. They were tagged, measured, wei~hed, examined for large external parasites, wounds, and reproductive cond:i - tion. Stoma ch contents were taken with a non-lethal, stomach-flushfog technique. The animals were then released at the site of capture. Al though they were originally found in the Ohio River, \\'hi tewater …


The Effects Of Mowing On The Rodent Community Of A Native Tall Grass Prairie In Eastern Nebraska, Cliff A. Lemen, Mary K. Clausen Mar 1984

The Effects Of Mowing On The Rodent Community Of A Native Tall Grass Prairie In Eastern Nebraska, Cliff A. Lemen, Mary K. Clausen

University of Nebraska State Museum: Mammalogy Papers

Our results indicate that mowing, like burning, greatly reduces the use of an area by Microtus and increases the density of Peromyscus maniculatus until the grass can grow back. Depending on the rate of growth of the grass this process can take more than a year. If the prairie is mowed every year to maximize the production of hay, populations of Microtus cannot be maintained at high densities.

The study site, Nine Mile Prairie, is one of the few natural tallgrass prairies remaining in eastern Nebraska. It covers about 240 acres and is located 5 km north and 9 km …


Muscongus Bay, Marine Wildlife Inventory And Evaluation, Alan E. Hutchinson, Sandra J. Lovett Feb 1984

Muscongus Bay, Marine Wildlife Inventory And Evaluation, Alan E. Hutchinson, Sandra J. Lovett

Maine Collection

Muscongus Bay, Marine Wildlife Inventory and Evaluation

by Alan E. Hutchinson and Sandra J. Lovett

Maine Department of Inland Fisheries and Wildlife

Augusta, Maine, February, 1984.

Contents: Preface / Acknowledgment / List of Tables / List of Figures / Introduction / Resource Inventory / Resource Evaluation / Resource Impact Assessment / Conclusions and Recommendations / References / Appendix


Simulation Analyses Of Space Use: Home Range Estimates, Variability, And Sample Size, Marc Bekoff, L. David Mech Jan 1984

Simulation Analyses Of Space Use: Home Range Estimates, Variability, And Sample Size, Marc Bekoff, L. David Mech

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

Simulations of space use by animals were run to determine the relationship among home range area estimates, variability, and sample size (number of locations). As sample size increased, home range size increased asymptotically, whereas variability decreased among mean home range area estimates generated by multiple simulations for the same sample size. Our results suggest that field workers should ascertain between 100 and 200 locations in order to estimate reliably home range area. In some cases, this suggested guideline is higher than values found in the few published studies in which the relationship between home range area and number of locations …


Effects Of Commercial Fish Removal On Sport Fish Populations In Two Arkansas Reservoirs, Tommie Crawford Jan 1984

Effects Of Commercial Fish Removal On Sport Fish Populations In Two Arkansas Reservoirs, Tommie Crawford

Journal of the Arkansas Academy of Science

Commercial netting occurred October through April, 1971-1976 on Nimrod Lake and from October through April, 1973-1977 on Blue Mountain Lake in west central Arkansas. Using 7.6 cm or larger mesh gill and/or trammel nets, commercial fishermen harvested commercial fishes (buffalofishes [Ictiobus spp.]; common carp [Cyprinus carpio], carpsuckers [Carpiodes spp.]; drum [Aplodinotus grunniens]; gars [Lepisosteus spp.]; suckers [Catostomidae); and catfishes [Ictalurus spp. and Pylodictis olivaris]). During the study period, cove rotenone samples were conducted on an annual basis. Fishes collected were placed into age classes and enumerated. Data were then grouped into general categories (black basses [Micropterus spp], crappie [Pomoxis spp.], …


Summary Account Of The Carolina Parakeet In Arkansas, Daniel Mckinley, Douglas A. James Jan 1984

Summary Account Of The Carolina Parakeet In Arkansas, Daniel Mckinley, Douglas A. James

Journal of the Arkansas Academy of Science

The extinct Carolina Parakeet (Conuropsis carolinensis) once was part of the Arkansas avifauna. The first two reports of the species in what is now Arkansas were made in 1673 and 1718 by early French explorers. The remaining records are from the 1800s when parakeets were found in nearly all parts of the state, often in abundance. The last literature reference for the species still definitely occurring in Arkansas pertains to birds present in the summer of 1885 along the White River at Newport


Microgeographic Variation In The Mexican Vole, Microtus Mexicanus, Meredith J. Hamilton, Gary A. Heidt Jan 1984

Microgeographic Variation In The Mexican Vole, Microtus Mexicanus, Meredith J. Hamilton, Gary A. Heidt

Journal of the Arkansas Academy of Science

Altitudinal variation was assessed in 115 (62 male; 53 female) Mexican voles (Microtus mexicanus) from six localities in Jalisco, Mexico. Univariate and multivariate statistical techniques were employed in the data analyses. A total of 49 skeletal measurements were investigated, and of these, 17 showed significant interlocality variation. Rostral breadth, depth of braincase, rostral height, width of third molar and nasal length were found to be the most variable characters. Component I (a size factor) accounted for 36% of the total phenetic variation; components II and III accounted for 30% and 19%, respectively. Larger individuals were found to occur at lower …


Limitations On Spatial Memory In Mice, Robert H.I. Dale, Martin Bedard Jan 1984

Limitations On Spatial Memory In Mice, Robert H.I. Dale, Martin Bedard

Scholarship and Professional Work - LAS

Rats have an impressive ability to remember locations they have visited. Two experiments used an eight-arm radial maze to determine whether mice showed two important characteristics of this spatial memory: its durability, and its dependence on stimuli outside the maze (extreme stimuli). In Experiment 1, food-deprived mice were allowed to eat from four of the eight arms of the maze then, after delays of 5 sec, 1 min, or 5 min, they were permitted to choose the remaining arms. Choice accuracy declined significantly with the longer delays, but always remained above chance. In Experiment 2, the maze was rotated 180° …