Presentation Title

Relationship between expression of combat behavior and circulating hormone levels in Crotalus atrox

Presenter Information

Alli StrickerFollow

Advisor Information

James Wilson

Presentation Type

Oral Presentation

Start Date

26-3-2021 12:00 AM

End Date

26-3-2021 12:00 AM

Abstract

For captive animals, abnormal group sizes have the potential to negatively affect the animals' behavior and physiology. Western diamondback rattlesnakes (C. atrox) are asocial animals and are not normally found in large social groupings. The rattlesnake canyon exhibit at Omaha's Henry Doorly Zoo currently contains 19 males and 2 females, an atypical social grouping for this species that could potentially cause increased expression of male combat behavior. This research aims to determine whether being housed in this atypical social grouping is having a physiological effect on the males in the exhibit by documenting their expression of combat behavior and examining the relationship between their combat behavior and their circulating levels of both corticosterone and testosterone. These hormone levels were compared to snakes housed individually, in a habitat that more closely matches their natural behavior. We predicted that animals housed socially would have higher levels of both corticosterone and testosterone than animals housed individually, and that within a large social grouping higher participation in combat would lead to higher levels of both corticosterone and testosterone. Combat behavior was also examined to determine if winner/loser effects are present in this exhibit. This research determined that both a winner effect and a loser effect are present in this exhibit. Preliminary examination of results suggests that there is no significant difference in circulating hormone levels between socially and individually housed animals, but that within the large social grouping circulating hormone levels might be related to individual expression of combat behavior.

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Mar 26th, 12:00 AM Mar 26th, 12:00 AM

Relationship between expression of combat behavior and circulating hormone levels in Crotalus atrox

For captive animals, abnormal group sizes have the potential to negatively affect the animals' behavior and physiology. Western diamondback rattlesnakes (C. atrox) are asocial animals and are not normally found in large social groupings. The rattlesnake canyon exhibit at Omaha's Henry Doorly Zoo currently contains 19 males and 2 females, an atypical social grouping for this species that could potentially cause increased expression of male combat behavior. This research aims to determine whether being housed in this atypical social grouping is having a physiological effect on the males in the exhibit by documenting their expression of combat behavior and examining the relationship between their combat behavior and their circulating levels of both corticosterone and testosterone. These hormone levels were compared to snakes housed individually, in a habitat that more closely matches their natural behavior. We predicted that animals housed socially would have higher levels of both corticosterone and testosterone than animals housed individually, and that within a large social grouping higher participation in combat would lead to higher levels of both corticosterone and testosterone. Combat behavior was also examined to determine if winner/loser effects are present in this exhibit. This research determined that both a winner effect and a loser effect are present in this exhibit. Preliminary examination of results suggests that there is no significant difference in circulating hormone levels between socially and individually housed animals, but that within the large social grouping circulating hormone levels might be related to individual expression of combat behavior.