A Wireless Wearable RF Sensor for Brumation Study of Chelonians

Abstract

We present a low-power wireless radio-frequency (RF) sensor to perform continuous vital-sign monitoring for chelonians in various stages of brumation. Due to their unique body structure, vital signs of chelonians cannot be recorded without substantial animal handling in previous methods, which would severely bias the brumation condition. In contrast, our sensor on harness can couple significant RF energy into various body parts to evaluate the heartbeat, respiration and activity levels. The self-contained unit is lightweight for ease of wearable deployment and low power to avoid unnecessary heat generation as well as frequent battery replacement. We recorded the shell temperature, heart rate, respiration rate and activity levels of a Russian tortoise during the entire brumation cycle and found that the heart rate correlated with the ambient temperature well, while the breath rate did not significantly reduce during brumation. This experimental study is minimally invasive and thus least biased.