Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 448-463). Available also in a digital version from Dissertation Abstracts.

A..11 species of Tapiridae and Rhinocerotidae are threatened or endangered in the wild. Captive populations have been established for most of these species, but successful management has proved challenging. Effective ex situ conservation strategies, however, rely on the ability of zoological institutions to maintain and breed these endangered species. In this study, I examined the captive environment to identify the factors associated with reproduction, mortality, and health of rhinos and tapirs. Zoological institutions in the North American region that currently housed rhinos and/or tapirs were surveyed in 2003. Attaining an approximately 90% response rate, I compiled information on the following variables to describe the captive environment: number of enclosures, enclosure type, enclosure area, number of animals, public viewing, percent of walls surrounding the enclosure, enclosure substrate, topography, vegetation, mud wallows, pools, shelters, percent shade, climate, diet, feeding regime, time spent by keepers, and vaccinations. Information regarding the incidence of health problems also was obtained through the survey. Studbook data was used to obtain life history and demographic information. Three species of tapirs [Baird's (Tapirus bairdii), South American (T. terrestris), and Malay (T. indicus)] and three species of rhinos [black (Diceros bicornis), white (Ceratotherium simum), and Indian (Rhinoceros unicornis)] were included in this study. Due to the small captive population sizes, genetic and demographic Allee effects were detected. While tapirs responded similarly to their captive environment, each rhino species responded differently. Both exhibit area and completely were associated with the responses of captive tapirs and rhinos. Climate also was an influential factor for both groups of species. Other key factors included density, diet, keeper time, percent of public perimeter, and vaccinations. Complex interactions among the variables were found, including a nonlinear relationship between mean exhibit size and reproduction for black rhinos. The results of this study can be used to improve the captive management of tapirs and rhinos. By identifying the patterns associated with successful reproduction, reduced mortality, and fewer health problems, we can move towards establishing self-sustaining populations for these species. This goal is critical for the continued husbandry and conservation of these species.

Discovered in 2000, the Gray Fossil Site provides a snapshot of the flora and fauna that lived during late Miocene to early Pliocene time in eastern Tennessee. These fossils occur in sediments consisting of fine-grained clays and sands of lacustrine origin, which were deposited after multiple sinkholes formed in the underlying Knox Group basement carbonates. Three-dimensional nearest neighbor analysis has been applied to fossils of Tapirus polkensis, characterizing the spatial patterns exhibited. These analyses determined the importance of taphonomic and depositional processes that occurred during the sites formation. Six characteristics were analyzed, four at the bone level including carnivore utilization, weathering, abrasion, and arthritis, and two at the specimen level, articulation and age class. Weathering, arthritis, and articulation, show clustered patterns indicating that the site had active predators, it consisted of many microenvironments, and deposition occurred in a passive setting. Although the current state of excavation makes any spatial analyses and taphonomic interpretations difficult, spatial analysis in both dimensions can be accomplished.

Individuals of Tapirus polkensis from the Gray Fossil Site exhibit an excellent level of preservation. Intact skulls collected from the site were arranged in a rough age class system separated into 7 categories based on the teeth present and amount of dental wear. Such an eruption series is useful for general comparisons amongst the individual tapirs; however, the classes do not represent an age in years due to a lack of data on living tapirs. Consequently, it is possible that some age classes may contain several years of a tapirs life, or comparatively only a few months. In this study I placed ages on individuals of T. polkensis from the Gray Fossil Site based on age data taken from The Baird's Tapir Project of Costa Rica (Baird's Tapirs, T. bairdii) ranging from several months to 7 years in age. As eruption data is only useful for aging tapirs up to 7 years, this study also took dental wear into account for adult tapirs. After aging all possible individuals in the sample, the sample was compared to other studies on perissodactyl population structure. Interestingly, the T. polkensis sample is remarkably similar to modern populations of Diceros bicornis.