Preliminary data on body temperature of the rock rattlesnake (Crotalus lepidus) from far west Texas

Background/Question/Methods Environmental temperatures along with other factors play an important role in the daily activities of reptiles. This includes rattlesnakes such as the Rock Rattlesnake, (Crotalus lepidus),  a snake that is commonly found in the mountain ranges of the Chihuahuan Desert. However, very little is known about the ecological aspects of this species, including thermal requirements. The main questions that we attempt to answer is what is the temperature range that C. lepidus select during the active seaon? And how do these prefered temperatures change during the entire season? We want to test if there are differences in body temperature bettween sexes as well. We present  body temperature data acquired through radio telemetry of the rock rattlesnake at the Indio Mountains Research Station (IMRS); a UTEP property located in Hudspeth County, Texas. The vegetation is typical shrub associations of the Chihuahuan Desert at an average elevation of 1200 m above sea level. Snakes collected were taken to the station’s laboratory and implanted with 5 g  transmitters, which are capable of measuring body temperature. After a week of transmitter implatation, snakes were relocated and radio-tracked at different times of the day using an antenna and a R-1000 telemetry receiver. We ontained body temperatures of rattlesnakes at different times of the day and also recorded body temperatures using digital recorders of individual snakes for 24 hours or more troughout different times of the active season. We are also using  temperature data-loggers inside snake models and located under microhabitats potentitally used by C. lepidus to record operative temperatures to test correlations with body temperatures.

Results/Conclusions

Until now, we have acquired diurnal and nocturnal body temperatures of four individual (three males and one female) C. lepidus for three to four days a week from July to mid-November 2007, and from April to mid-November 2008. Our initial results showed that the average body temperature of C. lepidus during the eight months of activity at the study area was 27.7 °C (n=10572). Snakes showed the highest average body temperature in June and July (30.5 and 30.2 °C, respectively). The lowest body temperature during this period (5°C) was recorded in October when Fall temperatures started to descend and the highest temperature (38.5°C) was recorded in May. Along with body temperatures, operative temperatures of microhabitats in the study area will be shown.