Title

Thermal Biology of the Northern Alligator Lizard (Elgaria coerulea): A Laboratory Study

Presenter Information

Taggert Butterfield
Daniel Beck

Document Type

Oral Presentation

Location

SURC 140

Start Date

17-5-2012

End Date

17-5-2012

Abstract

Many reptiles are known to regulate body temperature, but little is known about the thermal biology of the Northern Alligator lizard E. coerulea, which inhabits the Pacific Northwest. I used a thermal gradient to explore the following questions: 1) when given a diversity of temperature options, do Northern Alligator lizards show a specific temperature preference? If so, what is their “preferred” body temperature? 2) Does their body temperature preference change after feeding? And 3) does any tendency to either avoid other lizards, or group-up with other individuals, influence body temperatures of Alligator lizards in a thermal gradient. To address these hypotheses, I divided an ectothermatron (large cage, set up as a temperature gradient) into different temperature regions: one end at 15o C, the middle 25o C, and the other end 35o C. I placed six hideboxs in these regions and observed where lizards spent the most time. I conducted trials on 10 lizards over 4 months. For the “feeding treatment,” data were recorded up to 2 days after eating (meal size ~20 crickets); and 7 days post feeding for the “unfed treatment.” Lizards seemed to prefer intermediate temperatures (mean for all lizards Tb =25.2 ±2.91) but showed no differences in body temperatures before feeding (Tb =25.6±2.93) than after feeding (Tb=24.8±2.87). After feeding, however, lizards seemed to allow less variation in environmental temperature. Preliminary results suggest that lizards chose hide boxes independently of the presence of other lizards.

Faculty Mentor(s)

Daniel Beck

Additional Mentoring Department

Biological Sciences

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May 17th, 3:40 PM May 17th, 4:00 PM

Thermal Biology of the Northern Alligator Lizard (Elgaria coerulea): A Laboratory Study

SURC 140

Many reptiles are known to regulate body temperature, but little is known about the thermal biology of the Northern Alligator lizard E. coerulea, which inhabits the Pacific Northwest. I used a thermal gradient to explore the following questions: 1) when given a diversity of temperature options, do Northern Alligator lizards show a specific temperature preference? If so, what is their “preferred” body temperature? 2) Does their body temperature preference change after feeding? And 3) does any tendency to either avoid other lizards, or group-up with other individuals, influence body temperatures of Alligator lizards in a thermal gradient. To address these hypotheses, I divided an ectothermatron (large cage, set up as a temperature gradient) into different temperature regions: one end at 15o C, the middle 25o C, and the other end 35o C. I placed six hideboxs in these regions and observed where lizards spent the most time. I conducted trials on 10 lizards over 4 months. For the “feeding treatment,” data were recorded up to 2 days after eating (meal size ~20 crickets); and 7 days post feeding for the “unfed treatment.” Lizards seemed to prefer intermediate temperatures (mean for all lizards Tb =25.2 ±2.91) but showed no differences in body temperatures before feeding (Tb =25.6±2.93) than after feeding (Tb=24.8±2.87). After feeding, however, lizards seemed to allow less variation in environmental temperature. Preliminary results suggest that lizards chose hide boxes independently of the presence of other lizards.