Warm-season heat stress in moose (Alces alces)

Understanding howmoose (Alces alces (L., 1758)) are affected by temperature is critical for determiningwhy populations have recently declined at the southern extent of their North American range.Warm-season heat-stress thresholds of 14 and 20 °C are commonly used to study moose, but the variable response of free-ranging moose to temperatures above these thresholds suggests thatmoosemay bemore tolerant to heat.We studied zoo-managed cow and bullmoose to identify factors that influence warm-season heat stress. We found clear behavioral and physiological responses to thermal conditions. Moose selected shade, indicating solar radiation affects heat stress. Temperature and wind influenced respiration rates. Heat-stress thresholds for moose occurred at 17 °C when bedded under calm conditions and 24 °C when bedded under wind, demonstrating that the onset of heat stress is sensitive to wind and incorporating wind velocity into analyses would improve investigations of heat stress. Moose showing symptoms of gastrointestinal illness selected wind at lower temperatures than healthy moose, suggesting the effects of climate change will be compounded for health-compromised moose. Determining why moose are declining at the southern extent of their range may require understanding how temperature interacts with wind, moose health, and other