The late Pleistocene snake fossils from Sawmill Sink (Abaco, The Bahamas) represent five taxa: blind or thread snake (Scolecophidia indet.: either Leptotyphlopidae or Typhlopidae); Abaco boa (Boidae: Chilabothrus cf. exsul); rat snake (Colubridae: Pantherophis sp.); water snake (Natricidae: Nerodia sp.); and Cuban racer (Dipsadidae: Cubophis cf. vudii). Scolecophidia, Chilabothrus exsul, and Cubophis vudii still exist on Abaco and have been previously recovered in fossil deposits in the West Indies. In contrast, no forms of Pantherophis or Nerodia have been reported as fossils anywhere in the West Indies until now. This is the first evidence of any indigenous species of Pantherophis (living or extinct) in the Caribbean, whereas the only other indigenous Nerodia in the West Indies is the extant N. clarkii along the northern coast of Cuba. In being present on Abaco in late Pleistocene but not Holocene contexts, Pantherophis sp. and Nerodia sp. resemble 17 species that apparently did not survive the dramatic changes in climate, habitat, and land area associated with the Pleistocene–Holocene Transition in The Bahamas. It is likely that Pleistocene fossils of both Pantherophis and Nerodia will be found eventually on other Bahamian islands. With the discovery of these two snakes, the vertebrate fauna of Sawmill Sink now stands at 97 species, by far the richest in the West Indies.

The flexible shell of some oviparous reptiles has led to differences in nutrient mobilization and water relations when compared to their rigid-shelled counterparts. Flexible-shelled eggs gain more water during development, and because of the shell structure, yolk calcium content is higher than that of eggshells. When water availability is altered for reptiles with flexible-shelled eggs, differences in both energy and nutrient utilization are observed. This study was designed to determine the baseline metabolic rate during development for the snake, Pantherophis guttatus under normal conditions, and to observe how changes in eggshell calcium and water availability impact embryonic oxygen consumption. Eggshell calcium was decreased while water uptake was increased by removing the outer calcareous eggshell layer from some eggs. When eggs are left intact, an exponential increase in oxygen consumption is observed, supporting previous studies, while removal of the eggshell produces no effect on metabolism.

No description available.

Doctor of Philosophy / Department of Biology / Kimberly A. With / The loss, fragmentation, and degradation of grasslands have resulted in widespread declines in grassland birds. Nest predation is the leading cause of avian reproductive failure; therefore minimizing nest predation can lessen the severity of bird declines. Snakes are important predators of bird nests, but little is known about how snakes may enhance predation risk. To address this issue, I studied the habitat use, movement behavior, population genetic structure, and connectivity of snakes in the grasslands of northeastern Kansas. I addressed the connectivity of eastern yellowbelly racer (Coluber constrictor flaviventris) populations by using a landscape genetics approach at a broad scale (13,500 km2). I also radio-tracked the yellowbelly racer and Great Plains ratsnake (Pantherophis emoryi) at Konza Prairie Biological Station to understand their spatial ecology while simultaneously evaluating nest survival in grassland birds. Individual racers had limited dispersal (<3 km), but substantial admixture occurred within 30 km and populations were in migration-drift equilibrium and had high allelic diversity; therefore, racers must be abundant and continuously distributed for gene flow to be fluid throughout the region. Racers may be more likely to encounter bird nests, as they had more frequent movements and traversed greater distances on average than ratsnakes, which exhibited long periods of inactivity between directed movements. As for grassland birds, nest survival rates decreased with increasing shrubs and decreasing vegetation height. Discriminant function analysis revealed that successful nests were likely to occur in tall vegetation but reduced shrub cover, whereas higher shrub cover characterized snake habitats. Because snakes often use shrubs, nests in areas of increased shrubs may be at higher risk of predation by snakes. Targeted removal of shrubs may increase nest success by minimizing the activity of predators attracted to shrubs. Although predator removal is often a strategy for protecting bird populations, it may not be feasible in this instance, especially since snakes are a native component of the grassland community. Efforts to reduce snake predation on grassland bird nests should therefore focus on managing habitat within grasslands (i.e., shrubs) that influence snake activity, as no natural or anthropogenic habitat barriers currently limit snake movement across the landscape.