There's nothing quite as cute as a koala hugging a tree. While serving as a sight for sore eyes for ecotourists, this behavior also serves an important role for koalas: thermoregulation.
Hot days in the Australian outback can reach soaring temperatures and even the hardiest of animals may have a hard time coping. Fortunately, the cute and cuddly koala has developed an ingenious method of keeping cool during hot weather: hugging trees. Scientists working in the Australian outback used portable weather stations mounted on poles to measure the temperatures of the branches where koalas like to hang around and their findings were nothing short of remarkable. The researchers from the University of Melbourne in Australia found that koalas can regulate their internal temperatures by hugging cool tree trunks.
"We found trunks of some tree species can be over 5°C cooler than the air during hot weather," said University of Melbourne lead researcher Natalie Biscoe. Biscoe is also part of the university's School of Botany.
As global temperatures continue to rise, the new findings may shed light on how animals cope with increasing temperatures.
"Cool tree trunks are likely to be an important microhabitat during hot weather for other tree dwelling species including primates, leopards, birds and invertebrates," said Michael Kearney, another University of Melbourne researcher and co-author of the new study . "The availability of cooler trees should be considered when assessing habitat suitability under current and future climate scenarios."
The researchers found that by using the tree trunks to cool down, koalas can reduce the amount of water they need to drink in order to cool down on hot days by as much as half. The cooling mechanism is an important method of reducing the amount of heat stress that koalas experience in the wild. While the researchers already had an idea about the koalas' thermoregulation behavior, the measurements they took in the wild have confirmed their suspicions. The researchers published their findings in the online journal Biology Letters.
"About a quarter of the koalas in one population died during a heat-wave of 2009, so understanding the types of factors that can make some populations more resilient is important," said Andrew Krockenberger from the James Cook University. Krockenberger was one of the researchers who collaborated with the University of Melbourne scientists to complete the study.
As global warming continues to escalate, scientists are growing increasingly concerned over the number of species that become more and more vulnerable to increasing temperatures. In order to safeguard the future of these animals, further research into animal thermoregulation may be necessary.