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Thesis (Ph. D.)--Oregon State University, 1990. / Typescript (photocopy). Includes bibliography (leaves 127-137). Also available online.

A continuous-time model, describing the interaction between a "'facultative"' predator and a prey is used to study the consequences of exploitation of either the predator, the prey or both. The model assumes a logistic growth pattern in absence of the interaction. The change in steady-state levels of the associates due to different combinations of fishing intensities are described mathematically and diagrammatically. The effect of density of predation, on the equilibrium populations associated with the yield of either, or both, the predator and the prey are studied. Yield curves were constructed for both the predator and the prey under different fishing intensities of the other associate. The model is given in a discrete-time form, of which the stochastic version is derived to show the effect of intrinsic variability. The stochastic version was simulated on the computor through the use of random normal deviates. Fair agreement between the calculated values of the variances of the steady states, and those empirically found through simulation is listed. This simple structural model reveals that in such an association, fishing the prey population alone gives a lower maximum sustained yield than can be maintained, if the predator is also fished. It is hoped that such a model, which is a preliminary but a necessary step, will lead to a more comprehensive model applicable to natural fish populations. / Science, Faculty of / Zoology, Department of / Graduate

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science. Johannesburg, 2014. / Anteosaurs (Therapsida: Dinocephalia: Anteosauria) were the dominant terrestrial predators during the late Middle Permian period and became extinct at the close of the Tapinocephalus Assemblage Zone. Only two genera of anteosaurs, Australosyodon and Anteosaurus, are recognised from the Karoo rocks of South Africa. A newly discovered small anteosaurid skull from the Abrahamskraal Formation is fully described. Because of its relatively large orbits, the unfused nature of its sutures, and the lack of replacement teeth in the dental alveoli, the specimen is considered to be a juvenile Anteosaurus magnificus. A full computer-aided 3-D reconstruction of the skull enabled cranial measurements to be taken for an allometric analysis which included twenty-three measurements and eleven specimens. Positive allometry was found for four of the measurements suggesting fast growing in the temporal region, and a significant difference in the development of the postorbital bar and suborbital bar between juveniles and adults. Phylogenetic research shows that the Russian anteosaurids to be forerunners to Anteosaurus, and because the juvenile Anteosaurus (BP/1/7074) manifests many features of both Syodon and Titanophoneus, it is suggested that ontogenetic growth of Anteosaurus follows Haeckel’s Law.

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Thesis (M.Sc.)--College of William and Mary. / Vita. Includes bibliographical references. Also available via the World Wide Web.

This study is concerned with some of the processes that occur during the development of behaviour, and these are examined in the context how predatory behaviour develops in domestic cats, initially some of the problems that have beleaguered the study of behavioural development are examined and current issues in this field ae outlined. The experimental design of the study, the definitions of recorded behaviour and the methods of data analysis are then discussed. The study then focusses on the multiple effects that experiences in development can have on adult behaviour. It shows that cats were better able to catch prey as adults if they had had experiences of it as kittens, that cats specialized on the type of prey with which they had had prior experiences, and that little generalization to other prey types occurred in cats with experience of one prey type. Several other factors likely to affect adult predatory behaviour were than examined. Both the presence of the mother during kittens' exposure to prey, and experience of prey as adults were found to improve adult predatory competence. Object play had no effect on predatory behaviour. The study went on to relate the development of social play in kittens to the development of predatory behaviour. Some aspects of play became more associated with predatory behaviour aspects grew older, others less so. Different patterns of play appeared to increasingly come under separate types of control as kittens developed. One of the factors affecting the development of predatory behaviour, the effect of the mother, was then examined in detail. Some of the ways in which mothers encouraged their offspring to interact with prey were outlined together with the ways that offspring responded to the mother's predatory behaviour. Finally, the relationship between predatory behaviour in kittens and their subsequent predatory behaviour as adults was investigated. Many aspects of kitten predation were found to correlate with adult predatory activity. Some individuals that were poor predators as kittens showed competent predatory behaviour as adults. The implications of those findings were discussed in relation to the development of predatory behaviour, the development of play and the timing of events in kitten ontogeny.

Bibliography: pages 187-191. / The foraging of breeding Jackass Penguins Spheniscus demersus was studied in and around southwestern Cape Province, Saldanha Bay (33⁰ S, 18⁰ E), South Africa. Penguins are difficult to observe at sea. Hence, I devised a number of new techniques for studying the foraging behaviour of Jackass Penguins at sea. I built electronic and autoradiographic remote-sensing devices to measure swimming speed, distance travelled and time spent at each depth by foraging Jackass Penguins. Penguin swimming speed was reduced in proportion to the cross-sectional area of the devices, and results derived from birds wearing the devices had to be interpreted accordingly. Penguins do not regurgitate their stomach contents when handled, so I constructed a wet-offloading stomach pump which extracted 100% of the stomach contents. Using this pump, I determined that the rate of digestion of fish and squid by Jackass Penguins differed. Care is needed in diet interpretations where both fish and squid are major food items.

Coyotes fed upon agricultural carrion at feedlots operated by the Farmer's Investment Company (FICO) and Roisland Farms. Agricultural carrion was not available in the Whetstone area. The FICO feedlot stopped operating in May 1976, and carrion was not available there after that time. Coyotes were trapped and shot at the FICO feedlot from November 1975 through March 1976, from June through August 1976, and from May through August 1977. Coyotes were trapped at Roisland Farms in July and August 1976 and January and February 1977. A trapper collected coyotes in the Whetstone area from January through March 1976 and from November 1976 through February 1977. I operated a scent station line on the Santa Rita Experimental Range on a monthly basis from October 1975 through June 1976, from September 1976 through June 1977, and in December 1977. From data on the visitation of scent stations by coyotes, lagomorphs, and small mammals I calculated indices of monthly relative abundance for each animal group. There were no differences among the age distributions, weights, ovulation rates, and litter sizes of coyotes from the 3 study areas. The mean weights of all adult-sized male and female coyotes collected during this study were 11.1 and 9.3 kg, respectively. The overall mean ovulation rate and mean litter size were 4.1 and 3.4, respectively. At FICO and Roisland, 70 to 90% of yearling and adult females bred, but only 20% bred in the Whetstone area. There were more male than female coyotes at FICO, but sex ratios were not different from 1:1 at Roisland and Whetstone. The visitation rates of coyotes, lagomorphs, and small mammals fluctuated greatly during this study. Monthly visitation rates of coyotes differed significantly, but annual and daily rates did not. The visitation rates of both lagomorphs and small mammals were significantly different between years and among months, but not among days. Lagomorph and small mammal visitation increased significantly after the trapping of coyotes and the end of the FICO carrion supply in the summer of 1976. Coyote visitation appeared to decrease after the summer of 1976. Prior to the summer of 1976, the visitation rates of coyotes and lagomorphs were positively correlated, but the rates of coyotes and small mammals were not correlated. After the summer of 1976, coyote visitation was negatively correlated with both lagomorph and small mammal visitation. The distribution of coyote and lagomorph visits along the scent station line did not change after the summer of 1976. Small mammal visitation, however, increased in the distant section of the line after the summer of 1976. Coyotes visited stations located on the upwind side of the road more frequently than they stopped at stations on the downwind side. Lagomorphs showed no preference for either side of the road, but small mammals visited more stations on the downwind side of the road than on the upwind side. The breeding rate at FICO did not decrease after the carrion supply ended. It seems unlikely, therefore, that the high breeding rate at FICO was caused by feeding on carrion. The scent station technique has potential as a means of monitoring the monthly relative abundance of coyotes and certain prey groups. Unfortunately, visitation is a function of animal numbers and activity. Further research is required to quantify the relationship between visitation and abundance for each animal group.

Thesis (Ph. D.)--Duke University, 2007. / Includes bibliographical references.