National Geographic : 2015 Jun
PHOTO: STEVE GRIFFITHS (TOP); CLAESSENS LAB/MAURITIUS MUSEUMS COUNCIL Wild Things EXPLORE 84oF 106oF When things heat up down under, koalas know how to keep their cool. Now, thanks to infrared photography, humans can see how they do it. A 2014 study led by University of Melbourne ecologists showed that when summer temperatures climb up—often above 104°F—koalas climb down, press- ing their bodies close to the trunks of trees. Each tree has its own microclimate, says researcher Natalie Briscoe, and can be more than 12°F cooler than the air. So for a koala, whose belly fur is relatively thin, tree hugging is like standing in front of an open fridge. As a way to regulate body temperature, it’s more efficient than panting or fur licking—koala-cooling methods that use twice as much water. In a separate study, University of Sydney biologist Mathew Crowther found that koalas tend to chill out in “shelter trees” like casuarina rather than in “food trees” like eucalyptus. But in a heat wave either will do. As extreme heat becomes more frequent, tree hugging could become even more crucial. — Jeremy Berlin Koalas Keep Cool 3-D DODO RESURRECTION As technology gives dodos a closer look, their image may get a second chance. College of the Holy Cross paleontologist Leon Claessens and a team of re- searchers recently used a 3-D laser scanner on the world’s only complete dodo skeleton. The result—the first digitized dodo—may answer age-old questions about how the three-foot-tall, flightless birds looked, walked, and behaved. The dodo’s rep as an evolutionary failure is “entirely undeserved,” Claessens says. Dodos thrived on Mauritius for thousands of years before the Dutch came in 1598. By 1693 dodos were extinct, “a case study of human disruption.” — JB A thermal image (cooler temperatures are in purple) reveals how a lolling koala can weather a heat wave.