Jessi Krebs

Omaha's Henry Doorly Zoo


OHDZA Rattlesnake Welfare Assessment Project

Introduction: Attempts to improve animal welfare have commonly centered around three broad objectives: (1) to ensure good physical health and functioning of animals, (2) to minimize unpleasant ‘‘affective states’’ (pain, fear, etc.) and to allow animals normal pleasures, and (3) to allow animals to develop and live in ways that are natural for the species. Each of these objectives has given rise to scientific approaches for assessing animal welfare. An emphasis on health and functioning has led to assessment methods based on rates of disease, injury, mortality, and reproductive success. An emphasis on affective states has led to assessment methods based on indicators of pain, fear, distress, frustration and similar experiences. An emphasis on natural living has led to research on the natural behavior of animals and on the strength of animals’ motivation to perform different elements of their behavior.

All three approaches have yielded practical ways to improve animal welfare, and the three objectives are often correlated. However, under captive conditions, the natural behavior of animals may be challenged by their current circumstances, which could ultimately impact [good] welfare.

Background: Male combat in rattlesnake species is important for establishing dominance and plays an essential role in courtship behaviors (evidence is present that indicates subordinate males are refractory to courtship, while dominant males actively court females following combat). Our rattlesnake canyon exhibit features both males and females and copulation and combat behaviors are displayed. In the wild, males who are deemed subordinate and the ‘loser’ of combat, have opportunities to ‘flight’ or escape, however in captivity, this is a large constraint for these individuals deemed ‘losers’. For snakes who are considered the ‘losers’ of combat – do they have the ability to remove or recover from the incident?

Project Proposal: This behavioral observation project will be completed in an attempt to discover baseline data of exhibit space usage and overall activity budgets for the individual rattlesnakes within the rattlesnake canyon exhibit.

Each rattlesnake will be given a unique marker and behavioral data will be collected via two 8-Megapixel/4K Ultra HD Mini Dome Cameras -this is how we will be able to collect behavioral data in a controlled setting, where we can monitor their behavior based on the rattlesnake’s 24-hour activity schedule, not our 8-hour work schedule. In addition to behavioral data, we will also collect and analyze physiological data. Through fecals and sheds, we can track each snakes’ glucocorticoid levels (stress) and chart these levels over the course of the study.

Throughout our baseline data collection, of both behavioral and physiological data, we will be able to pinpoint individual specimens that are participating in combat behaviors. While we will continue the study on the collective group, our focus will be directed towards these individuals participating in combat, more specifically the ‘losers’. The goal of this study is to answer two questions:
1. Does losing a combat battle affect the behavior and exhibit spatial use of that individual rattlesnake?
2. Secondary question: if losing does have a negative welfare impact, what steps should be taken?