Browsing by Subject "Bovidae"
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Item Bull-switching in African Bovid Herds: Assessing Best Practices for Breeding Management in Waterbuck(2011-10-21) Jones, Renee Crystal MichelleTo implement sustainable ex-situ management of big ungulate herds such as African Waterbuck (Kobus ellipsiprymnus), one strategy is to place a vasectomized male with females during the sub-optimal season for breeding and subsequently replace him with an intact male during the optimal breeding season. However, information is needed on the effects of vasectomy and the long-term effects on social well-being of individuals used in this "bull-switching" treatment, which is designed to enhance well-being of the whole herd. In this study, behavioral observations were conducted in three periods (pre-treatment, treatment, post-treatment) 2-months in length. Focal individual observations were used to systematically record (a) continuous samples on video (6-min duration; n = 595), (b) instantaneous samples of proximity (n = 951), and (c) field notes of all-occurrences of social interaction (courting and antagonistic). The quantitative and qualitative analyses revealed a significant effect of treatment on three (courtship, escalation, and proximity) out of four measures (deescalation was not affected). Courtship and escalation behaviors increased significantly during the treatment (G2 = 46.35; df=1, P <0.001; z=6.60). The treatment was associated with a significant change in proximity for females (G2 = 17.21; df=1; P <0.001; z=2.31) and other males (G2 =16.10; df=1; P <0.001; z=-3.57). Overall, (1) there was no substantial change with social well-being of the vasectomized male before removal and after reintroduction; (2) the male proximity did not fluctuate significantly with the juvenile males, calves, and other species; and (3) the vasectomized male and the intact male exhibited similar social well-being characteristics. Considering current environmental changes, the treatment did not result in a decline of the social well-being of females and calves, but it did for non-breeding males. Courtship declined in post-treatment, but this was due to the increased percent of pregnant females. During post-treatment, a change in ratio of green grass and supplementary feed pellets possibly affected de-escalation in the context of interspecies interactions. The change of the proximity of the herd was associated with increased heat and use of shaded areas in the pasture. The treatment resulted in a change in relationship with the satellite male and juvenile males in the herd.Item The paleoenvironments of early hominins in the Omo Shungura Formation (Plio-Pleistocene, Ethiopia) : synthesizing multiple lines of evidence using phylogenetic ecomorphology(2014-05) Barr, William Andrew, active 21st century; Reed, Denné N.Ever since Darwin claimed that expanding savannas were the driving force behind humanity's divergence from other apes, our understanding of human evolution has been inextricably linked to the environmental context in which our ancestors evolved. This dissertation explores various aspects of the use of one method of paleoenvironmental reconstruction -- bovid ecomorphology -- and provides new data on paleoenvironmental conditions in the Omo Shungura Formation (Plio-Pleistocene, Ethiopia). Chapter 2 uses phylogenetic simulations to explore the performance of Discriminant Function Analysis (DFA) on simulated ecomorphological data containing phylogenetic signal. DFA is shown to "over-perform" in situations in which predicted and predictor variables both contain phylogenetic signal. Phylogenetic Generalized Least Squares (PGLS) is shown to be a very useful technique for explicitly testing functional hypotheses in ecomorphology while controlling for phylogenetic signal and body size. Chapter 3 presents a functional analysis of the bovid astragalus, which is one of the most commonly preserved bones in the fossil record. Several functional hypotheses linking habitat-specific locomotor performance with the morphology of the astragalus are tested using PGLS. Strong support is found for three of these hypotheses. Thus, the astragalus is shown to be a useful ecomorphological predictor element, a point that is confirmed by the DFA analyses in Chapter 4. Chapter 5 provides new paleoenvironmental data on the Omo Shungura Formation based on habitat reconstructions from astragalar ecomorphology in addition to dietary reconstructions based on dental mesowear. Astragalar data point to a major environmental shift beginning ~2.58 Ma, which is later in time compared with some prior habitat reconstructions using different methods. Furthermore, astragalar data show environmental fluctuations of similar magnitude later in the sequence. Mesowear data on the Shungura Tragelaphini do not offer evidence for any significant grazing adaptation, in spite of relatively high carbon isotope signatures reported based on studies of tooth enamel. These data raise questions regarding the diet of fossil Tragalephini.Item Reconstructing the Habitat Mosaic of Australopithecus robustus: Evidence from Quantitative Morphological Analysis of Bovid Teeth(2012-02-14) Brophy, JulietThis research better resolves the environmental mosaic that is typically reconstructed for the A. robustus-bearing faunal assemblages of South Africa and evaluates whether A. robustus were habitat specialists or habitat generalists by testing whether they are associated with numerous, different reconstructed habitats, or if they can be associated with a single, more homogeneous habitat type. Determining the habitat preferences of A. robustus holds important implications for understanding the behavior of these hominins and, potentially, for understanding whether their ultimate extinction might have been climatically influenced, as fluctuations in the environments associated with the robust australopiths provide direct evidence about the responses of hominins to environmental change. To achieve this, a 2-dimensionsal morphometric tool was developed for accurately identifying the abundant bovid teeth that are found in direct association with the hominins using Elliptical Fourier Function Analysis. More accurate taxonomic identifications facilitate more precise estimates of the relative abundance of ecologically sensitive bovids, allowing for finer resolution when segmenting the various components of the reconstructed habitat mosaics. The fossil bovids abundances were compared across the assemblages over time in order to define the environmental mosaic in each assemblage and to determine if environmental heterogeneity existed across the assemblages. The relative abundances of the bovid fossil assemblages and A. robustus were compared to assess the habitat preferences of these hominins. A. robustus were not consistently associated with a particular habitat type suggesting that perhaps they were habitat generalists, capable of surviving in multiple types of habitats.