Rethinking Captive Heating: Effect of Infrared Radiation on the Radiated Tortoise (Astrochelys radiata)
Publication Type: |
Journal Article |
Year of Publication: |
2021 |
Authors: |
Nichola J Willis, Andrew Quayle, James E Brereton |
Publication/Journal: |
Captive and Field Herpetology |
Keywords: |
astrochelys radiata, heating, husbandry, IR-A, IR-B |
Abstract:
In the wild, reptiles are exposed to the entire infrared spectrum (IR-A, IR-B and IR-C wavelengths), yet many zoological collections rely on IR-C to provide heat to their animals. This study investigated whether the addition of IR-A and B wavelengths affected the behaviour and enclosure use of a group of captive radiated tortoises (Astrochelys radiata). Modified Spread of Participation Index (SPI) was used to assess the evenness of exhibit use. This is the first published study using SPI on a reptile species, despite its practicality at addressing abiotic gradients and depth-based zones that are commonplace within herptile enclosures. The study identified a 31% reduction in tortoise basking behaviour when exposed to IR-A and B emitting bulbs (p < 0.001, r= 0.402) which simultaneously resulted in a wider variety of behaviours being expressed, including changes in inactivity (p < 0.001, r= -0.309) and drinking (p < 0.001, r= -0.139) behaviours. In addition to behavioural changes, the provision of IR-A light resulted in more even enclosure zone use, potentially making it an interesting application for improving herptile captive husbandry. IR-A and B lighting may be an important consideration for improving captive herptile welfare and facilitating an animal’s expression of natural behaviours. Despite some interesting results, this study did not yield enough
information to fully support the provision of IR-A lighting to captive reptiles, thus, future, more in-depth studies with larger sample size, observation counts and subjects amongst different taxa will be required. Potentially, with further studies and repetitions, this could have large and positive implications for the industry; ones that would derive from a relatively simple, and inexpensive/cost-effective change/modification
of a light bulb. It is the author’s aim that this work will provide a useful foundation for future studies.