Abstract
Body thermal activities of the homed viper, Cerastes cerastes gasperettii, collected from the Riyadh region of Saudi Arabia were investigated. Thermoregulation in snakes is mainly accomplished by behavioral activities. Thirty-six adult snakes were collected and transferred to a reptilian lab to conduct thermal selection studies using a thermal gradient chamber. Cloacal temperatures were recorded for 3 successive days and nights after every hour. During summer, daily activity of C. c. gasperettii started at sunset and continued overnight when air temperature was ((X) over bar = 34 degrees C) and body temperature was ((X) over bar = 29.8 degrees C). Under laboratory conditions, the mean selected body temperature (SBT) was 29.2 degrees C during the day, while it was 27.2 degrees C during the night without any significant difference. A refrigerated mini lab was used to determine the critical temperature minimum (CTmin) where body temperature was taken after every 3 minutes. Likewise, the critical temperature maximum (CTmax) was determined using another group of the horned viper. The mean CTmin recorded in the lab was 7.3 degrees C, while CTmax, was 45.5 degrees C. It could be concluded that body thermal activities of C. c. gasperettii is greatly influenced by ambient temperature whether in the field or under laboratory conditions.