## 1 Introduction  
Livestock welfare and production are notably affected by the thermal environment. High ambient temperature compromises animals' efficiency because maintaining body temperature becomes the highest priority instead of using nutrients for production purposes, e.g., milk and meat production [1]. Although advancements in management systems such as cooling systems and modern barn construction alleviate some negative effects of heat stress (HS), globally, it is estimated that livestock producers may face a financial loss of $40 billion annually by the end of the 21 st century [2]. Physiological adaptations such as increased respiration rate [3] and sweating [4] are employed as heat abatement mechanisms by domestic animals intended to reduce heat loads and increase heat dissipation. Traditionally, measurements of body temperature are the most widely used to assess or predict HS in livestock [5]. With the advancement of technology, the ability to monitor and predict physiological responses like body temperature automatically is progressing rapidly [6]. However, these automated temperature monitoring technologies may miss opportunities to identify changes within heat-stressed environments (i.e., before severe shifts in productivity occur) because deviation in temperature will only reflect when animals have exceeded the homeothermic limits. Nevertheless, these technologies aim to reduce human intervention, decrease the costs associated with management, and increase animal welfare through an improved understanding of stress exposure. In this context, methods used to measure body temperature and physiological responses to HS using remote sensinginclude vaginal and rectal probes [7], rumen boluses [8], thermal imaging [9], and ear canal sensors [10] as an alternative to monitoring temperature directly, monitoring animal behaviors during exposure to heat stress may allow for a more precise understanding of stress levels and adaptation across a temperature gradient, rather than signaling only when animals have exceeded their thermoregulatory mechanisms. Animals in HS environments tend to alter their natural behavior in order to maintain euthermia in comparison with animals in thermoneutral conditions. Rumination is reduced in cows [11] with shifts in ruminants patterns, with more than 60% of the daily rumination occurring at night [12]. Moreover, standing bouts have been demonstrated to increase in hot temperatures [13] as an attempt to enhance the body surface area and support cooling. Although previous studies have characterized some of these changes related to HS, e.g., a decrease in feed intake and its effects on production being the most studied [14; 15], other behavioral changes in ruminants undergoing HS, such as the frequency and duration of activities including grazing, eating, lying, and standing behaviors have not been well studied. Moreover, there is limited information available regarding measurements of HS in sheep when compared to other species, such as dairy cattle. Enhancing our understanding of HS in sheep could significantly benefit the sheep industry once sheep serve as a cost-effective animal for extensive systems. A challenge with using behavior to evaluate animal stress responses induced by climate is that behavioral adaptations may differ considerably between scenarios with gradual versus extreme shifts in the environment. For example, during extreme temperature changes, animals may show much more obvious behavioral adaptations, whereas those employed during gradual temperature shifts may be more challenging to observe and detect. Previously, inertial measurement units (IMU) to monitor and classify animal behaviors have been used in thermoneutral environments [16; 17; 18]. However, the robustness of the behavior classification algorithms used in these sensors within thermoneutral environments has not been well characterized.