During the day, flying-foxes roost in patches of trees, known as camps, which may contain tens to thousands of individuals. As a result, they can be susceptible to extreme weather conditions.
Heat stress - or hyperthermia - occurs when the body produces more heat than it can dissipate. Flying-foxes are generally affected when temperatures exceed 42°C and roost vegetation in their camps doesn't provide enough shade refuge. Post-mortems suggest that flying-foxes mainly die from resulting heat shock i.e. the body can no longer function effectively.
The severity of a heat stress event is likely to be reduced by:
- enough understorey and mid-storey vegetation for shelter from extreme heat
- dense crown vegetation to provide shade
- access to enough water.
Severity is likely to be increased when camps are disturbed at critical times during a heat stress event, potentially forcing individuals to leave their cooler microhabitats and become fully exposed to the extreme heat.