FIGURE 1.

(a) Thermal performance curve : Physiological performance is dependent on body temperature in a strongly non‐linear way. All animals have a range of ‘optimum’ body temperatures across which physiological performance is maximised. Performance declines at body temperatures outside of this range, and loss of function is more precipitous at hyperthermic than hypothermic body temperatures. (b) Scholander–Irving model of endotherm thermoregulation: Metabolic and evaporative water loss rates change strongly non‐linearly with increasing ambient temperature, allowing endotherms to maintain stable body temperatures across a range of ambient temperatures by increasing or decreasing metabolic heat production and evaporative heat loss.