Use of infrared thermography to detect reactions to stressful events: does animal personality matter?

Abstract

The study of the relationship between animal stress and personality for free‐ranging animals is limited and provides contrasting results. The perception of stressors by an individual may vary due to its personality, and certain personality traits may help individuals to better cope with them. Using non‐invasive infrared thermography (IRT), we investigated the link between physiological and behavioral components expressed during an acute stress event by free‐ranging Fremont's squirrels (Tamiasciurus fremonti). We expected that, during the acute stress event of being approached by the researcher, individuals that showed a fast pace‐of‐life syndrome (bolder, more active, and less social/more aggressive) based on an arena test would exhibit stronger sympathetic‐adrenal‐medullary system reactivity showing a more intense stress‐induced hyperthermia (high core body temperature and low peripheral temperature) than individuals with a slow pace of life (shy, less active, and more social). We successfully employed IRT technology to images of Fremont's squirrels with identification of the individuals’ body parts (eye, nose, ear, hind foot). However, we found no support for our hypothesis. Squirrels’ body surface temperatures told us more about a squirrel's external environment and less about the thermal state of the body in that environment following a stressful event. Further studies need to assess how to make IRT effective and efficient in the field and improve its performance in studying the relationships between physiology and personality in wildlife.

Assessing thermal ecology of herpetofauna across a heterogeneous microhabitat mosaic in a changing aridland riparian system

“…In this study, we exercised precautions to overcome regional heterothermy and other sources of error. We captured IRT at relatively short distances to animals (<1 m) to reduce errors related to temperature or atmospheric conditions (Playà-Montmany and Tattersall 2021, Taylor et al 2021), analyzed mean thermal data values from multi-pixel shape functions, across animal heads and torsos, rather than rely upon single-pixel 'spot' values (Rowe et al 2020), and controlled for other potential sources of variation, such as srad (Weathers 1972), vpa (Li et al 2021), and behavior (Mazzamuto et al 2023), during statistical modeling (Tattersall 2016). With such, we derived relative T B to T S relationships for multiple taxa, which may be more practical for wildlife management purposes than precise core temperature.…”