Effects of Habitat Modifications on Behavioral Indicators of Welfare for Madagascar Giant Hognose Snakes (Leioheterodon madagascariensis)

摘要

Although historically understudied, the empirical evaluation of captive reptile welfare is becoming more common, and zoos continue making modifications to their reptile facilities with the goal of improving welfare. In this study, we evaluated the impacts of habitat modifications on the behavior of five Madagascar giant hognose snakes ( Leioheterodon madagascariensis ) housed in the Holden Reptile Conservation Center at the Detroit Zoo. The snakes’ enclosures were modified from smaller stainless steel boxes with newspaper substrate and plastic hide boxes to larger enclosures with open glass fronts and naturalistic elements. Along with nearly doubling enclosure size, the new enclosures featured a deep sand/mulch mixture for substrate instead of newspaper, as well as corkbark furnishings in addition to the plastic hide boxes. We hypothesized that the modifications made to the enclosures would provide opportunities for the expression of species-typical behaviors, such as exploration, digging (an important foraging behavior for hognose species), and locomotion, as well as increased behavioral diversity and overall activity levels. Each individual was observed for a total of 7.7 hrs with approximately 3.8 hrs in both the baseline and modified conditions. Data were collected using both scan and all-occurrence sampling methods in 10-min focal observation sessions, twice daily, three times a week. Generalized linear mixed models showed that the modified habitats increased behavioral diversity and environmental exploration compared to baseline data. One snake showed substantially different behavioral trends due to a unique medical condition, highlighting the need to consider individual differences when evaluating snake welfare. These results support our hypothesis and provide evidence that habitat modifications informed by ecology and natural history are successful in promoting species-typical behaviors as indicators of positive welfare in snakes.