In just about every koala photo, the furry Australian marsupial is clinging to a tree. Now, scientists have figured out why: To the koala, a tree trunk is an air conditioner. A new study by a team of Australian and U.S. researchers found that koalas seek out and hug trees to keep themselves from overheating.
Koalas don’t den, so they have to find other ways to cool off. Panting helps, through a mechanism called evaporative cooling, but the animals also lose precious water that way. To figure out just how dependent koalas are on trees for cooling, Natalie Briscoe of the University of Melbourne and other researchers tracked the behavior of 37 koalas during winter and summer, observing their interaction with trees. They also noted tree type, height and location, and measured the microclimate of the sites using portable weather stations mounted on an extendable pole. During hot weather, the ...
