Ecologist Jason Van Weenen says bats in Adelaide's Botanic Park are getting more and more stressed. They're starting to cluster in the trees in large clumps, which signals trouble.
The Australian state of New South Wales has issued a health warning after a summer heat wave hit bat communities hard.
And in the state of South Australia, bats are collapsing from the heat in the capital's Botanic Park, where staff are scrambling to keep them safe and away from visitors.
"As they're getting more and more stressed they start to congregate in the trees in real large clumps, and that's a clear sign that they are in trouble," ecologist Jason Van Weenen said.
Australian media are reporting that stressed out bats are falling out of the trees, or getting tangled up in electricity wires.
Health officials are warning people not to try to help the bats, because of the risk of infection. It's clearly not easy being a bat when the heat is on.