A fourier regression analysis of body temperature of the American opossum, Didelphis virginiana

Abstract

The daily variation of body temperature of the North American opossum, Didelphis virginiana, was examined by means of radiotelemetry, and the data were statistically evaluated by a Fourier periodic regression analysis. Four opossums were individually housed at 21°C and two of these opossums were also housed at 7°C ambient temperature. Throughout the investigation the light cycle was LD 9:15 (08:30‐ 17:30h), and body temperatures were recorded each half hour. A prominent 24 h rhythm was observed for the body temperatures of all opossums; for each regression analysis the 24 h harmonic was statistically significant and was the largest portion of the trend. A visual inspection of the fitted curves revealed single peaks and troughs throughout the 24 h period. It is concluded that the opossum exhibits a 24 h rhythm of body temperature comparable to other metatherians.

Abstracting Key words:

• 24‐hour rhythm
• body temperature
• Didelphis virginiana
• radio‐telemetry
• Fourier regression analysis

Notes

Science and Mathematics Teaching Center, Michigan State University, East Lansing, Michigan 48824. Present address: Science Education Centre, Western Australian Institute of Technology, Bentley 6102, Western Australia.

Department of Psychology, The University of Iowa, Iowa City, Iowa 52242.

Departments of Physiology and Biophysics, The University of Iowa, Iowa City, Iowa 52242.