 Media playback is unsupported on your device Media caption Dr Michael Kearney from the University of Melbourne explains how the koalas hug trees to regulate their temperature 
 
 Hugging trees helps koalas to keep cool, a study has revealed. "It can be a really useful way of getting rid of heat on a hot day," said study co-author Michael Kearney, an ecologist at the University of Melbourne in Australia. If we had thermal vision, it would have been an obvious thing Dr Michael Kearney, University of Melbourne 
 
 While PhD student Natalie Briscoe was studying the koalas' behaviour, she noticed that in the winter the animals would stay high in the trees - up near the leaves feeding. The region is cool most of the year, but during the summer, the temperature routinely spikes above 104 degrees Fahrenheit (40 degrees Celsius), Kearney said. But measurements of the temperatures of the tree trunks showed that, on days as hot as 39C, they were up to seven degrees cooler than the air. Koalas seek non-food trees to cool down 
 
 The researchers measured four species of eucalyptus and one type of acacia. [See Images of the Tree-Hugging Koalas] 
 
 "As it got hotter the koalas went farther down the trees and started to really hug onto the tree trunks," Kearney told Live Science. It's not clear exactly why their preferred tree trunks are cool, but one possibility is that they pull in a lot of groundwater, which stays closer to the annual average air temperature, rather than the current air temperature, he said. Climate change planning 
 
 Koalas' food (and hugging) trees will change their range with the hotter and drier weather brought by climate change, Bill Ellis, a wildlife researcher at the University of Queensland in Australia, who was not involved in the study, wrote in an email to Live Science. But the new study suggests that food may be a smaller consideration in preserving koala habitat than previously thought, he said. Koalas hug trees for quick cooling 
 
 In hot weather animals and birds often avoid overheating via 'evaporative cooling'. In a study published in the Royal Society journal Biology Letters, scientists used thermal cameras to reveal that, in hotter weather, the animals moved to the lower, cooler parts of the trees. Follow Tia Ghose on Twitter and Google+.
– Using thermal cameras, researchers in Australia uncovered the science behind a habit that seems, well, cute: Koala bears hug trees to cool themselves. It turns out that tree trunks can be up to 12 degrees cooler than the air, and with Australia's recent hot spells rising well above 100 degrees, koalas get extra huggy. Conversely, in the cold of winter, the marsupials tend to climb higher into trees, closer to the leaves they eat. The scientists came to their conclusion after using thermal cameras on a particularly hot day. "If we had thermal vision, it would have been an obvious thing," a University of Melbourne researcher tells the BBC. "You could see the koala sitting on the coolest part of the tree trunk with its bottom wedged right into the coolest spot." And in doing so, koalas manage to conserve a substantial amount of water: They typically cool themselves by panting, LiveScience explains, with heat escaping their bodies by way of the moisture leaving their mouths. Modeling showed tree hugging halved the amount of water that would otherwise be lost. The study also explains why the marsupials have been spotted in acacia trees, which aren't a food source: Those trunks get cooler than eucalyptus trunks, notes Australian Geographic. As for why the trees in general are cooler, researchers say it's possibly because they pull in nearby groundwater, whose temperature doesn't fluctuate as much as air temps do. (Earlier this year, Australia's heat caused thousands of dead bats to fall from the sky.)