干旱区生态环境知识资源中心

Historically, studies of reptilian thermal biology have compared ambient temperatures (T-a) to body temperatures (T-b) from the animal under study, with T-b usually taken from the cloaca and various instruments being used to measure T-b. The advent of surgically implanted miniature temperature loggers has offered the opportunity to test the efficacy of cloacal T-b as a measurement in thermoregulatory studies. We expected that there was a difference between skin, cloacal, and core T-b’s. Temperatures were measured from various positions on leopard tortoises (Stigmochelys pardalis) using thermocouples and miniature temperature loggers, including surgically implanted temperature loggers. Measurements of temperature from various positions on and in the tortoise were significantly different from T-a. Cloacal T-b’s were significantly lower than all other body temperatures measured, and core T-b’s were significantly different from cloacal T-b, skin and carapace temperatures. In addition, significant differences were found between measures of temperature from other parts of the body. The variations between core T-b, cloacal T-b and other measures of T-b indicated that there are large thermal gradients within the body of a relatively large tortoise at any given time with cloacal T-b not an accurate measure of core T-b. (C) 2013 Elsevier Ltd. All rights reserved.