Semester of Graduation

Spring 2023


Master of Science (MS)


Veterinary Clinical Sciences

Document Type



Louisiana pine snakes (Pituophis ruthveni) are one of the rarest snake species in North America, and federally classified as “threatened” (United States Fish and Wildlife, 2018). Recent establishment of sustainable captive breeding populations combined with decades of field research by conservation biologists has led to several advancements in our knowledge of this species; however, further investigations into health parameters and the physiology of this species are needed to optimize management of captive populations.

One recent investigation highlighted the difficulties in reliably differentiating the sexes in P. ruthveni using traditional tail probing techniques (Katz et al., 2020). Prior to pursuing the study that is the primary focus of this thesis, we examined sexually dimorphic traits not previously described in this species that can be used to help differentiate sexes in a field or clinical setting.

Glucocorticoids such as corticosterone have been used to monitor health and stress in captive and wild populations of several reptile species (Romero & Wikelski, 2001; Tylan et al., 2020; Moore et al., 1991). Most studies focus on plasma corticosterone; there are relatively few investigations in which accumulated corticosterone concentrations in keratinized tissues has been examined (Berkvens et al., 2013; Zena et al., 2022; Gormally & Romero, 2021). This thesis represents the first investigation measuring plasma and shed skin corticosterone in P. ruthveni. No clinically significant trends in corticosterone concentrations correlating to health parameters or exposure to stressors were identified. Our results reflect similar findings in the only other study quantifying corticosterone from the shed skin of two snake species, Lamprophis fuliginosus and Sistrurus catenatus catenatus (Berkvens et al., 2013). While this may indicate that shed skin corticosterone is unreliable as a means of monitoring stress in snakes, further investigations into factors influencing the relationship of corticosterone in keratinized tissues, health, and stress are warranted.

The population used in this study was previously diagnosed with subclinical Cryptosporidium sp. infection. We performed a retrospective evaluation of morbidity and mortality in this Cryptosporidium-positive population, and identified common diseases and syndromes which may affect other captive populations of P. ruthveni or may be seen as comorbidities in other Cryptosporidium-positive snakes.



Committee Chair

Nevarez, Javier G.



Available for download on Friday, March 27, 2026