An Introduction to the Ethology of the Uinta Ground Squirrel (Citellus armatus)

This study describes behavior of the Uinta round squirrel (Citellus armatus) in a free-living population. Its objective is to provide basic behavioral information on a small mammal which can fill in part of the gaps in our knowledge of behavior and social organization of the vertebrates. This would contribute to the long-term goal of viewing the progressive evolutionary changes in behavior from lower forms to man. Tinbergen has done much experimental work with animals, but he cautions biologists not to begin experimental work until they have a knowledge of the animals\u27 general behavior. In his book Social Behaviour in Animals (1953), he states that initial behavioral research should be broad, descriptive, and observational in nature. This is necessary before attempting investigation of specific behavioral problems in order to place each behavior pattern in its proper perspective . Accordingly, this study attempts to describe the spectrum of ground squirrel activity aboveground. Further, within the limited scope of a broad descriptive study, it attempts to ascribe possible causation, function, and origin to some of these activities. The beginner sees a welter of activities and postures in the ground squirrel. However, with time one learns that there are general patterns of behavior in the apparent chaos. A given situation, such as feeding or fighting, is sufficiently stereotyped to enable one to eneralize about the activities and postures that occur. This paper presents just such generalizations. All descriptions are of adult ground squirrels in the study area unless otherwise indicated

Employer\u27s Liability for Employee He Was Compelled to Hire

Should an employer be liable for the torts of his employee if he was compelled to employ him?The master is charged with the obligation of selecting competent workmen. Therefore, if the element of employee selection is removed as a prerogative of the employer, does not this remove the master-servant relationship? If the employer through no fault of his own cannot completely direct and control the employee, is not the necessary privity between master and servant absent? Is it reasonable that the employer be liable for the misconduct of a person whose selection and/or control has been taken out of his hands? A review of existing case law is required to answer these questions

Sound Communication in the Uinta Ground Squirrel

Numerous investigators have studied sound communication in animals in recent years. Most of these studies have been on birds, insects, or cetaceans, particularly the dolphin. Most of the studies on terrestrial mammals have been of the natural history type, and the authors have given an orthographic rendition of any sounds produced by that particular species. Few definitive studies have been done. There have been a few attempts to determine cause and function of sounds in mammals (Arvola, lImen, and Koponen, 1962; Bartholomew and Collias, 1962; Rowell and Hinde, 1962; Andrew, 1963). No quantitative studies on sound communication in Citellus have been made. Balph and Stokes (1963), Burnett (1931), Fitch (1948), Gordon (1943), Linsdale (1946), and Manville (1959) have described the natural history and ecology of various ground squirrels. The purpose of my study was to catalog the sounds given by the Uinta ground squirrel (Citellus armatus), to determine the cause and function of each sound, and to see how these sounds represent adaptations to life in the animal\u27s habitat

On the Behavioral Responses of Free Uinta Ground Squirrels to Trapping

Biologists often trap animals to obtain information on them. If trapping is selective toward some animals, the information may be inaccurate. Most mammalogists know or suspect that their trapping techniques (reviewed by Hayne, 1949; and Stickel, 1954) contain sources of bias. Since trapping remains the only feasible way to obtain information on many animals, researchers have tried to discover sources of sampling error and refine their techniques. They have found that one major source of difficulty may lie in the behavior of animals. Individual animals seem to respond differently to trapping, both initially and through learning (Geis, 1955; Crowcroft and Jeffers, 1961; and others). However, researchers seldom observe the behavioral responses of animals to traps. They infer information from capture data. Perhaps an empirical approach would shed more light on the relationship between behavior and trapping. The present study is such an approach. The study concerns the behavioral responses of adult Uinta ground squirrels, Citellus armatus, to trapping. I based the study on the direct observations of known individuals in a wild population. My primary objective was to learn how animals respond to a trap, to capture, and to recapture. My approach was both that of a population ecologist interested in factors affecting trapping success and that of a behaviorist interested in the effect of trapping procedures on the behavior of animals. I conducted a broad ecological and behavioral study of the population (Balph and Stokes, 1963) before beginning the research on trap response, which helped me select parameters and develop procedures. I also conducted a pilot study on deer mice, Peromyscus maniculatus, in the laboratory to test some procedures and the design of the trap-response investigation

Population Ecology of Uinta Ground Squirrels

The behavior and ecology of Uinta ground squirrels (Spermophilus armatus) at the Utah State University Forestry Field Station northeast of Logan, Utah, were studies 1964—71 to determine the role of behavior in population regulation. In 1968 the population was reduced experimentally to about one—half the previous density. The study area consisted of a lawn area where resident squirrels more than replaced themselves, and an area of mixed shrubs and grasses where they did not. Surplus squirrels from the lawn raised the population density off the lawn. Also, habitat suitabilities varied with population densities. Hence, densities in the two areas were not proportional to habitat preferences. Before the reduction the population density fluctuated widely but the mean change for 5 yr was approximately zero. A potentially high rate of increase was curtailed by disappearance of juveniles and yearlings; juveniles tended to disperse from the natal burrow. The principal changes following the reduction were increases in percentage of yearling squirrels breeding and of juveniles remaining on the study area. Litter size and proportion of adult females breeding did not change significantly, but losses during hibernation, due in part to badger predation, decreased. Dispersal of squirrels from the study area played a key role in population regulation. Dispersers probably suffered higher mortality than sedentary squirrels, but dispersal was not necessarily maladaptive for the individual. Dispersers may have been unable to produce young at high densities; thus emigration offered the only opportunity for reproduction

Alarm calling behavior of the thirteen-lined ground squirrel, Spermophilus tridecemlineatus

Alarm calling in a population of thirteenlined ground squirrels, Spermophilus tridecemlineatus , was studied over a three-year period. Data on ground squirrel reactions to human and canine approaches and to the approach or presence of avian predators were used to quantify alarm calling behavior.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46905/1/265_2004_Article_BF00299364.pd

Optimal foraging and fitness in Columbian ground squirrels

Optimal diets were determined for each of 109 individual Columbian ground squirrels ( Spermophilus columbianus ) at two sites in northwestern Montana. Body mass, daily activity time, and vegetation consumption rates for individuals were measured in the field, along with the average water content of vegetation at each ground squirrel colony. I also measured stomach and caecal capacity and turnover rate of plant food through the digestive tract for individuals in the laboratory to construct regressions of digestive capacity as a function of individual body mass. Finally, I obtained literature estimates of average daily energy requirements as a function of body mass and digestible energy content of vegetation. These data were used to construct a linear programming diet model for each individual. The model for each individual was used to predict the proportion of two food types (monocots and dicots) that maximized daily energy intake, given time and digestive constraints on foraging. Individuals were classified as “optimal” or “deviating”, depending on whether their observed diet was significantly different from their predicted optimal diet. I determined the consequences of selecting an optimal diet for energy intake and fitness. As expected, daily energy intake calculated for deviators (based on their observed diet proportion) was less than that for optimal foragers. Deviating foragers do not appear to compensate for their lower calculated energy intake through other factors such as body size or physiological efficiency of processing food. Growth rate, yearly survivorship, and litter size increase with calculated energy intake, and optimal foragers have six times the reproductive success of deviators by age three. Optimal foraging behavior, therefore, appears to confer a considerable fitness advantage.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47783/1/442_2004_Article_BF00318534.pd