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Female-female aggression in the Gila monster (Heloderma suspectum)
Gordon W Schuett1,2, Karl H Peterson3, Anthony R Powell4
1Department of Biology | Neuroscience Institute, Georgia State University, Atlanta, GA, USA.
Royal Society Open Science
|May 14, 2023
Summary
Female Gila monsters exhibit intense aggression, including biting and envenomation, during social interactions. Osteoderms may protect them during these fights, unlike more ritualized male contests.
Area of Science:
- Ethology
- Herpetology
- Animal Behavior
Background:
- Historically, animal aggression research focused on males.
- Recent studies highlight female-animal aggression, especially in lizards.
- Female-female aggression in Gila monsters (Heloderma suspectum) is documented here.
Purpose of the Study:
- To document and describe female-female aggression in captive Gila monsters.
- To develop a qualitative ethogram of observed aggressive behaviors.
- To investigate potential protective mechanisms against injury during fights.
Main Methods:
- Conducted four dyadic trials with eight adult female Gila monsters.
- Developed a qualitative ethogram to categorize aggressive behaviors.
- Performed bite-force experiments and analyzed osteoderms.
Main Results:
- Observed prevalent and intense female-female aggression, including biting, envenomation, and lateral rotation.
- Postulated that osteoderms provide protection against serious injury during fights.
- Contrasted female aggression with more ritualized, less biting-intensive male-male contests.
Conclusions:
- Female Gila monster aggression is intense and involves unique behaviors like envenomation and rolling.
- Osteoderms likely play a protective role in mitigating injuries during these aggressive encounters.
- Further research is needed to understand the ecological and social functions of female aggression in this species.
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