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Research Profile
Preferred body temperature of tuatara
Anne Besson, PhD student
Dr Alison Cree (supervisor)
Department of Zoology
University of Otago
Dunedin
New Zealand
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| Using a thermocouple to measure the body temperature of a tuatara. The thermocouple is inserted into the tuatara's cloaca. Photo by Raewyn Empson |
Tuatara (Sphenodon sp) once occurred in southern New Zealand, but now occur naturally only on islands in Cook Strait (S. punctatus “Cook Strait” and S. guntheri) and further north (S. punctatus punctatus). A proposal exists to reintroduce tuatara of Cook Strait origin to an ecosanctuary near Dunedin (The Orokonui Ecological Sanctuary). In order to know if such reintroduction is feasible, Anne is invesigating the preferred body temperature of tuatara and verifying that the southern New Zealand can offer this temperature for them to thermoregulate.
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| Thermal gradient apparatus Photo by Anne Besson |
Preferred body temperature is the temperature that an animal chooses in a thermal gradient. The thermal gradient consists of a metal sheet lining the bottom of a big shallow wooden box. Four narrow runways are placed on top of the gradient. The top of each runway is covered with Perspex to keep the animals confined and to reduce air movement. Air temperature within the runways ranges from about 30°C at the warm end to about 10°C at the cold end. The procedure for measuring preferred body temperature is well-established for reptiles and has been shown to be safe for New Zealand lizards and juvenile tuatara in captivity.
Ten male tuatara, that were released in Karori Sanctuary, have been tested. Animals were weighed, measured and then placed individually in the thermal gradient about two hours before the first observation in order to settle in the new environment. At each observation time, the body temperature was measured by a cloacal thermocouple (skin surface temperature was also measured with an infrared thermometer for comparison). Observations were made four times during the day at: 10am, 3pm, 10pm and 10am again the second day.
Profile Anne did her undergraduate degree in Ecology and Evolution at the University
of Burgundy in France, and moved to Dunedin to begin her PhD under the She is interested in reptile ecology and behaviour. |
Thermoregulatory behaviour of tuatara has been studied in the past but there is still much to be learnt especially with respect to reintroducing the species to its former range. These results will help us to determine whether the thermal habitat in southern New Zealand is suitable for Sphenodon punctatus. Information on preferred body temperature will also be of value to captive husbandry.
Papers and Presentations
- Alison Cree, Diane Campbell-Hunt, Anne Besson. The return of the reptiles. International Festival of Science, Dunedin, July 2006.
- Anne Besson. Preferred body temperature, activity responses and tolerance
to temperature: a comparison between 2 sympatric lizards from southern New
Zealand (H. maculatus and O. maccanni). SRARNZ conference, Dunedin,
February 2007.
Related Links
Acknowledgments
I would like to thanks Raewyn Empson and KWS staff for their help during the project, the Department of Conservation and Ngati Koata for their approval, Dorothy Picken for welcoming me at her lovely place during the project, Ian Dickson for building the thermal gradient and the Zoology Department for their financial support.
| Article Ref #0012 Published June 12, 2007 |
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