Theses (M.S.)--Marshall University, 2005. / Title from document title page. Includes abstract. Document formatted into pages: contains vi, 98 p. including col. illustrations and maps. Bibliography: p. 65-70.

Thesis (M.S.)--University of Wisconsin--Stevens Point. / Submitted in partial fulfillment of the requirements of the degree Master of Science in Natural Resources (Wildlife), College of Natural Resources.

Thesis (M.S.)--Rutgers University, 2009. / "Graduate Program in Ecology and Evolution." Includes bibliographical references (p. 178-183).

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / The standard treatment for rattlesnake envenomation (RSE) is antivenom. The clinical course of patients treated with antivenom is well described. Prior to 2000, only a whole IgG AV (IgGAV) associated with high rates of hypersensitivity reactions (HSS) was available to treat RSE. Since 2000, Crotalidae Polyvalent Immune Fab (FabAV), which has a better safety profile than IgGAV, has been primarily used. Patients with RSE may not be treated with AV for a variety of reasons including history or perceived risk of HSS, patient refusal, drug shortage, or clinical impression that AV is not indicated. Research Question: What outcomes are associated with moderate to severe RSEs treated without antivenom?

Call number: LD2668 .R4 1966 G3

The facial pits characterizing the snake subfamily Crotalinae have been demonstrated to be important as thermoreceptors in detecting the presence of prey animals and in directing the stroke towards them. So specialized a receptor as the pit organ, if it is to survive, must be functionally effective. If this organ is important in locating prey under natural conditions it would be expected that if these pits were destroyed this importance would be reflected in growth rates, weight changes,, or survival. In twenty of forty snakes collected in the spring of 1963 the pits were destroyed by electric cautery. After weighing, measuring, and marking, the snakes were released at the point of capture. The growth of the recaptured cauterized and non-cauterized snakes was compared. In addition, controlled tests were made with the recaptured snakes, using live mice and light-proof boxes to determine the effectiveness of cautery. A significant statistical difference was found in the growth rates of the females, the cauterized snakes growing more slowly. No difference was found in the growth rates of the males. However, the controlled tests indicates the pits to be important to the males as well as to the females. Weight changes were too variable to reveal differences between normal and cauterized snakes and no difference in survival was evident between the two treatments. To overcome the effect of individual variation in growth rate further study is required of larger samples over a longer time period. / Science, Faculty of / Zoology, Department of / Graduate

Thesis (M.S.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references (ℓ. 68-84)

Class of 2016 Abstract and Report / Objectives: The purpose of this study was to assess trends in the anatomical bite location, circumstances, and legitimacy of rattlesnake envenomations managed by the Arizona Poison and Drug Information Center (APDIC) between the years of 2002 to 2014. Methods: The Institutional Review Board approved this retrospective database analysis in which deidentified patient case information was extracted from the APDIC electronic medical record database. Descriptive and demographic variables collected included: age, gender, anatomical bite location, circumstance, and alcohol involvement. Variables were analyzed by student researchers to determine the legitimacy. Researchers compared demographic variables by year and month to assess for trends. Results: A total of 1,738 rattlesnake envenomations were analyzed for the 13 year study period. The number of cases per year varied, but not significantly, p=0.069. A statistically significant (p<0.005) upward trend in average age occurred. No significant difference in cases involving females was found between study years (p=0.171). Alcohol involvement was not statistically significant, p=0.46. An upward trend (p<0.005) in legitimate rattlesnake envenomations was demonstrated. Conclusions: Envenomations from 2002 to 2014, showed an upward trend in age, but similar distribution of gender. An increasing number of envenomations were determined to be legitimate, possibly related to the increasing number occurring to the foot/ankle, as well as the increasing number related to gardening and walking outside/taking out the trash. This trend may also be due to the lack of adequate data related to alcohol involvement.

Long-distance translocation (LDT), the relocation of an animal outside of its home range, is a popular strategy for mitigating conflict between humans and venomous snakes. While LDT has been demonstrated to prevent a snake’s return to the location of capture, it may result in increased mortality, magnitude and frequency of movements, and activity range sizes. Thus, it has generally been discouraged. However, the effects of LDT on stress physiology and thermoregulation have gone largely unstudied in reptiles. To elucidate these effects, we conducted an experimental LDT on Western Rattlesnakes (Crotalus oreganus) on Vandenberg Air Force base in California. Fourteen snakes were monitored, beginning in mid July 2012 and ending in early September. Each was implanted with a radio transmitter and iButton temperature data logger within the coelomic cavity. In late August, seven snakes were translocated to similar habitat, approximately 30 kilometers away, where they were monitored for 9-13 days. Prior to translocation, all snakes were tracked every other day, while after translocation all snakes were tracked every day. A ‘Before-After Control-Impact’ (BACI) experimental design was used, with a dedicated control group, but also with the translocated group serving as control prior to the act of translocation. We collected data on snake body temperatures (T­b) and temperatures (T­e) of physical operative temperature models (OTMs) that simulated non-thermoregulating snakes and allowed for a comparison of habitat thermal quality between our two study sites. Together, T­b and T­e allowed for a formal assessment of thermoregulatory effectiveness. Additionally, blood concentrations of corticosterone (CORT), the primary stress hormone in reptiles, and testosterone (T), a metric of male reproductive ability that is often negatively associated with CORT, were assayed just prior to translocation and again at the end of the study. During each of the two sampling periods, in addition to baseline hormone concentrations, stressed hormone concentrations were assayed following the application of an acute stressor (the baseline blood draw plus one hour’s captivity in a plastic bucket). We also studied the effect of LDT on the CORT and T response (stressed concentration minus baseline concentration). Furthermore, we evaluated how LDT impacted a suite of behaviors related to defense and movement, as well as snake body mass and body condition index (BCI). Finally, we assessed the effects of LDT on movements and spatial use (activity range size). We sought to assess the effects of LDT on movements, spatial use, and behavior in order to facilitate comparison with other translocation studies, as well as to evaluate those impacts in a physiological context. In addition to assessing the impact of LDT on CORT and T separately, we evaluated a relationship between the two steroid hormones, and, using a model selection approach, we evaluated relationships between CORT and T and movements and spatial use. The thermal quality of the habitat at our two sites did not differ and we found no effect of LDT on snake body temperature or thermoregulatory effectiveness. We found that spatial use increased following LDT, since the average 100% minimum convex polygon (MCP) activity range size of our translocated snakes was greater than that of our control snakes during the post-translocation period. However, movements (mean distance moved per day and total distance moved) were unaffected by LDT. Translocation was not found to affect snake body mass or BCI, indicating that snake energy demands did not increase as a result of LDT. Of the behaviors that we recorded, many (rattling, tongue-flicking, fleeing, moving vs. stationary when found) were observed too infrequently to carry out satisfactory parametric analyses, though a qualitative assessment leads to the conclusion that LDT did not affect them. The effect of LDT on how often our snakes were visible was marginally significant, but post-hoc testing found no differences. Nonetheless, the translocated snakes tended to be visible more often than the controls, during the post-translocation period. We found no effect of LDT on the percentage of a snake’s body sunlit when visible. Our translocation was not found to any CORT metric, while for T, the only metric that was affected was the baseline concentration. Baseline T was found to be higher in translocated snakes than in control snakes following translocation. We found some evidence for a positive relationship between CORT and T for baseline and stressed concentrations. Our model selection procedure found little evidence for a relationship between snake movements and spatial use and either CORT or T. Our results are encouraging in that we did not find that LDT disrupts thermoregulation or results in a condition of chronic stress, as indicated by the CORT results. The positive effect of LDT on baseline T is somewhat mysterious, but studies on mammals suggest that increased T may aid in spatial learning and memory. Since the site that a snake is translocated to is entirely novel, an elevated capacity for spatial learning and memory could be beneficial to a translocated snake. Our finding that spatial use increased following LDT agrees with other studies of LDT in snakes, but some studies have found that movements increased following LDT, while we did not. In addition to snake movements being unaffected, we translocated our snakes within a relatively thermally benign climate in coastal central California. Translocations carried out in more extreme climates, with either cold winters or hot summers may indeed result in an effect on thermoregulation and a state of chronic stress. Consequently, we advocate further study of the physiological effects of LDT on other snake species in a variety of climates. Additionally, while it was our goal to study the short-term effects of LDT, more long-term studies, which follow the snakes through the entire active season and the winter hibernation period, may be informative.

Stress is a physiological state induced by disturbance or adverse environmental conditions and is modulated by the glucocorticoid hormone corticosterone (CORT) in reptiles. Stressors can have various impacts on vertebrate trait expression and may affect survival or reproduction. Little is known about the effects of chronically elevated CORT in free-ranging reptiles, or the effect of disturbance stress on venom composition in captive snakes. In chapter 1, we investigated the effects of researcher induced disturbance on CORT levels and venom composition in a group of captive Northern Pacific rattlesnakes (Crotalus oreganus). Venom protein concentration and plasma CORT levels were compared before and after two weeks of unpredictable bouts of cage vibration, and to a non-vibrated control group. CORT levels were also assessed one week into vibration treatment. We found no effect of vibration treatment on CORT levels or on venom composition, and within-snake relative protein abundance was highly repeatable, although some variation was observed. We found a strong correlation between changes in relative abundance of several proteins and CORT. These results led us to believe that while differential forms of researcher-induced disturbance may not affect venom composition, significant changes in baseline CORT, or chronic stress, may affect the venom phenotype. In the next study, we investigated the effects of chronically elevated CORT in a wild population of radio-telemetered Southern Pacific rattlesnakes (C. helleri). Snakes were implanted intra-coelomically with either crystalline CORT or sham implants. Prior to implant and for two week periods thereafter, we sampled blood, venom, defensive behavior, and body temperature (Tb). Thermal data logger implants recorded snake Tb each hour. Snakes were tracked daily for one month, and detectability, defensive behavior, movement, home range size and thermal parameters were calculated for each group during the periods between samples. Stress reactivity was assessed as change in CORT from baseline after one hour of acute confinement stress. CORT implants led to elevated baseline CORT for at least two weeks in treatment snakes, showing that our treatment was successful. Chapter 2 describes the effects of CORT treatment on venom parameters. Increased baseline CORT was associated with increased activity of venom protein phospholipase A2, indicating that CORT may have direct effects on regulating venom protein activity. Overall, venom activity was repeatable within individual snakes. Chapter 3 describes the effect of CORT on behavioral, ecological, and physiological variables. Implant treatment led to decreased average Tb in weeks two and three. We detected a trend for lower baseline CORT to predict a greater magnitude of acute stress response. Snakes with higher testosterone levels exhibited higher defensive behavior scores. Overall, there were no other effects of implant treatment. Our results suggest that rattlesnake thermoregulation is impacted by chronic stress, which could affect other aspects of their metabolism and ecology. Results of both studies suggest baseline CORT may direct both the activity and relative abundance of venom proteins in different manners, a hypothesis which deserves further investigation using proteomic tools. When responding to an acute stressor, rattlesnakes may secrete CORT until a threshold response is reached, regardless of baseline levels. Overall, rattlesnakes appear resilient to the effects of researcher-induced disturbance in the laboratory and to two weeks of chronically elevated CORT in the field, as no change was detected in many of the parameters investigated.