Abstract
Simple SummaryThis study aimed to clarify the relationship between manual capture techniques, blood lactate levels, and other varying factors in order to minimize physiological stress during manual capture and restraint events of zoo-housed crocodilians. While following the St. Augustine Alligator Farm Zoological Park’s capture and restraint protocol, 53 blood samples from ten crocodilian species were collected and analyzed for lactate. These measurements were then related to specific behavioral and extrinsic factors. We sought to define blood lactate as a new welfare marker for crocodilians in zoos. Based on our findings, we are able to recommend some best practices for manual capture methods for crocodilians.Species-specific welfare indicators are important in promoting positive welfare for zoo animals. Reptiles are a notoriously understudied group in regards to behavior, welfare needs, and husbandry requirements. Using opportunistically obtained samples, we evaluated how blood lactate is affected by variation in manual capture and restraint in crocodilians. Lactate is an indicator of anerobic metabolism in reptiles. It offers a relatively simple and indirect way to assess physiological stress. Determining the best way to reduce struggling during capture and associated stress is of great importance to these species’ overall welfare. Blood samples (N = 53) were collected from 10 different species of crocodilians. It was found that age class was a significant predictor variable of lactate levels after capture, and longer handling time seemed to cause an increase in lactate. Finally, draining enclosure pools for a small number of the captures was associated with higher lactate levels compared to other capture factors that were recorded. This study showed that welfare of captive crocodilians could be improved by shortening the duration of physical restraint events when possible. Developing objective measures of welfare and establishing baseline recommendations for care and handling of crocodilians will ultimately promote and improve their wellbeing, along with that of other understudied reptiles in zoos.
Highlights
Despite increased studies in recent years, there is still relatively little known about the welfare indicators of reptiles housed in zoos and aquariums
For zoo-housed crocodilians, there are numerous behavioral and extrinsic factors involved in improving their overall welfare [5], yet little has been empirically studied from a zoo perspective
The magnitude of lactate elevation was to age class and it seems the duration of capture appears to influence lactate values
Summary
Despite increased studies in recent years, there is still relatively little known about the welfare indicators of reptiles housed in zoos and aquariums ( zoos). Captive studies of behavior and welfare are more common in mammals compared to other vertebrates, with little attention given to the understanding of reptiles’ natural behaviors because they are thought to have a simpler lifestyle [1,2,3,4]. For zoo-housed crocodilians (alligators, crocodiles, caimans, and gharials), there are numerous behavioral and extrinsic factors involved in improving their overall welfare [5], yet little has been empirically studied from a zoo perspective. Most research is from crocodile farms where the primary focus is to promote quality hide and meat production [6]. There is a current need for more research on the welfare requirements of zoo-housed crocodilians
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
