Behaviour Influences Thermoregulation of Boreal Moose During the Warm Season

Management of large herbivores depends on providing habitats for forage supply and refuge from risks of temperature, predation and disease. Moose () accumulate body energy and nutrient stores during summer, while reducing the impact of warm temperatures through physiological and behavioural thermoregulation. Building on the animal indicator concept, we used rumen temperature sensors and GPS collars on captive moose ( = 6) kept in large natural enclosures to evaluate how behaviour and habitat selection influence the rate of change in rumen temperature during the growing season on the Kenai Peninsula, Alaska, USA. We compared movement and habitat selection of individual females during tolerance days (daily amplitude in rumen temperature was ≥1.2°C in 24 h) with those of control days (daily amplitude in rumen temperature was < 1.2°C) before and after the tolerance day. Moose moved more during tolerance days (172 m • h; 95% confidence intervals (CI)  = 149-191 m • h) than on control days (151 m • h; 95% CI = 128-173 m • h). The rate of change in rumen temperature (°C • h) declined with low to moderate movement rates that were probably associated with foraging in all habitats. Movement only increased the rate of change in rumen temperature at high activity (~ > 500 m • h). Additionally, the relationship between rate of change in rumen temperature and movement rate was different during tolerance and control days in open meadow and wetland habitats. In all habitats except wetlands, the rate of change in rumen temperature increased while resting, which probably is a result of diet-induced thermogenesis. Our study demonstrates that the behavioural choices of moose on the landscape are associated with the rate of change in rumen temperature and their ability to thermoregulate. Wildlife managers must consider high-value habitats where wildlife can employ both behavioural and physiological mechanisms to tolerate warm ambient conditions in a landscape of forage, predators and pests.