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The reference of a koala bear often conjures up an image of an adorable spoon - nosed puppet cocking its head to one side while clinging to a tree diagram .
Now , scientist have enter out why the iconic Australian marsupials clinch trees : The proboscis help thekoala bearskeep cool , harmonize to a new subject area .
Koalas live in trees in Australia and eat mostly eucalyptus leaves.
" It can be a really useful way of getting rid of high temperature on a hot sidereal day , " tell study co - source Michael Kearney , an ecologist at the University of Melbourne in Australia .
tree diagram huggers
Given thatkoalasspend so much time in trees — the marsupial live in Australia ’s woodlands where they crunch on leaves and log Z’s — nobody wondered why they hugged the short pants . mass just think they were taking a break on a more unchanging spot after eat on leaves in the branches , Kearney tell . [ Marsupial Gallery : A Pouchful of Cute ]
As such , the breakthrough came as a surprise . Kearney and his student , doctoral candidate Natalie Briscoe , were trying to predict how the woodland creatures on French Island , near Melbourne , would determine their organic structure temperature as the continent heat up due toclimate variety . The neighborhood is cool most of the yr , but during the summer , the temperature routinely spike out above 104 arcdegree Fahrenheit ( 40 degree Celsius ) , Kearney said .
Briscoe mensurate jazz and shade levels using a portable weather post , but did n’t find any spectacular trends . Then she point to an infrared thermometer , which measures temperature based on thermic radioactivity , at the tree trunks the koala bear were hugging . The trunks were considerably cool than the ambient air temperature — sometimes by as much as 9 degrees F ( 5 degree C ) , Kearney said .
She also noticed the native bear clinging to acacia trees , even though they normally eateucalyptus foliage . [ See image of the Tree - Hugging Koalas ]
" As it amaze hot the koalas plump far down the Tree and start to really hug onto the Sir Herbert Beerbohm Tree trunks , " Kearney told Live Science . " That seemed unknown to us until we figured out that the tree are a bit cooler . "
Stay nerveless
Koala bears pant to keep coolheaded , letting evaporated wet from their mouth carry heat out from their bodies .
When the team modeled koala bear heating transfer , they found the tree diagram - dwellers save half the piss they would have used panting if they embrace trees instead .
koala bear get most of their water from their diet , but because eucalyptus leaf are laced with a toxin , the koalas can use up only a limited amount before the toxin harms the animate being , Kearney said .
So tree - hugging could be decisive to their survival on hot days , by set aside them to cool off without emaciate treasured water through panting , Kearney said .
It ’s not clear exactly why their preferred tree trunk are nerveless , but one possibility is that they pull in a lot of groundwater , which stay closer to the one-year average melody temperature , rather than the current air temperature , he pronounce .
Climate change design
Koalas ' intellectual nourishment ( and hugging ) trees will change their range with the hotter and dry conditions bring by climate change , Bill Ellis , a wildlife researcher at the University of Queensland in Australia , who was not involved in the cogitation , publish in an email to Live Science .
But the newfangled subject field suggests that food may be a small condition in preserving kangaroo bear home ground than previously thought , he allege .
" As long as we plant tree koalas will eat , perhaps the other trees we plant just need to provide the right mixture of protection and heat swallow hole machine characteristic , " Ellis say . " It ’s quite an interesting conception , but non - native tree might be the futurity for koalas — as long as they also have the correct fodder . "
far northward in the koala ’s range , the strain is muggy and itfeels hotter , so scientists should see how tree - hugging plays out in in unlike location in the kangaroo bear ’s home ground , Ellis said .
" humidness means that the power of vaporization for cooling is reduced , " Kearney aver . So tree - hugging may be even more important up north , where evaporative cooling does n’t lick as well , he said .
The study was published today ( June 3 ) in the journal Biology Letters .
