When animals are hot, they eat less. This potentially fatal phenomenon has been largely overlooked in wild animals, researchers from The Australian National University (ANU) warn in a new study.
According to lead author Dr Kara Youngentob, it means climate change could be contributing to more deaths among Australia's iconic marsupials, like the greater glider, than previously thought.
"Hot weather puts all animals off their food. Humans can deal with it fairly well; we usually have plenty of fat reserves and lots of different food options," Dr Youngentob said.
"But it's much more serious for animals with highly specialised diets, like greater gliders. If they don't eat regularly, they don't meet their nutritional requirements to stay alive. They also get most of their water from their food, so not eating leads to dehydration too.
"Even night-time temperatures can get hot enough to cause nocturnal animals to lose their appetite during heatwaves.
"A lot of the focus until now has been on the impact of climate change on food quality and quantity, but the bigger picture here is that hot animals eat less even if they have plenty of food," Dr Youngentob said.
President of the Far South Coast Branch of National Parks Association NSW David Gallan said the ANU paper is an important one and has significant implications for climate and land management.
"It's important in land management to have research papers such as these to inform long term decision making, not just at the local level but across the country. Much of our forested landscape has been disturbed through fire, land clearing and logging," Mr Gallan said.
According to the ANU research, marsupials have trouble processing the natural toxins in eucalyptus leaves at high temperatures. But they now warn hot temperatures alone, even with a toxin free diet, can stop them from eating enough to stay alive.
Dr Youngentob said there are a few things we can do to address the issue, including protecting sources of food.
"If you're eating less, the small amount you do eat needs to be more nutritious. Not all eucalypts have the same level of nutrients, so we need to identify and protect those areas of the forest that have the best quality food for these animals," Dr Youngentob said.
"We should restore degraded forest with more nutritious food trees too.
"We also need to look closely at what makes some forests cooler, and what contributes to forests getting hotter so we can protect and expand those cooler microclimates."
Mr Gallan said the research paper demonstrates the importance of addressing climate change seriously, as well as protecting and restoring our forested landscapes so that greater gliders have access to nutritious leaves.
"It may also point to the need to conserve larger trees with a cooler microclimate and more insulated hollows that gliders need for shelter and breeding.
"Greater glider populations have crashed over the last twenty years and we can't afford to compound past mistakes in land management if we want the world's largest marsupial glider to survive," he said.