Captivity Affects Head Morphology and Allometry in Headstarted Garter Snakes, Thamnophis sirtalis

Area of Science:

• Herpetology
• Conservation Biology
• Evolutionary Morphology

Background:

• Amphibian and reptile populations are declining globally.
• Captive breeding and headstarting programs are common conservation strategies.
• Low survival rates after reintroduction are a significant challenge for these programs.

Purpose of the Study:

• To investigate the impact of captivity on head morphology in the eastern garter snake (Thamnophis sirtalis).
• To compare head size and allometric growth patterns between captive-raised and wild snakes under different dietary conditions.

Main Methods:

• Eastern garter snakes were raised under three distinct dietary treatments.
• Head morphology was measured and compared between captive-raised snakes and wild individuals.
• Allometric growth patterns of head size were analyzed for each diet group.

Main Results:

• Snakes raised on all three captive diets exhibited smaller head sizes compared to wild eastern garter snakes.
• Significant differences in head size were observed among the three captive diet treatments.
• Allometric patterns of head size growth varied significantly across the different diet treatments.

Conclusions:

• Captivity, particularly diet, can induce significant changes in head morphology of the eastern garter snake.
• Reduced head size in captive-raised snakes may limit their prey options upon reintroduction.
• These findings have implications for the success of headstarting and reintroduction programs for various reptile species.