As if koalas could be any more adorable than they already are, they tend to spend a lot
of their time hugging trees.
Now I get living in trees- that’s a good way to avoid predators since larger animals
usually can’t climb them.
But there's plenty of animals, like most monkeys, that live in trees, and they don’t feel
the need to hug them all the time.
And for a long time, zoologists weren’t sure why koalas felt the need to wrap themselves
around the tree so much.
And yeah maybe this doesn’t sound like the most pressing scientific question, but according
to a new research study, they’re actually hugging the trees to stay cool.
Australia is not one of the most hospitable of places to live.
It’s really hot a lot of the time, there’s not much water around, and food can be hard
to come by.
So koalas have to keep cool somehow, but they have a big problem: they don’t sweat.
Now, koalas aren’t the only animals that can’t sweat.
Dogs, for instance, can only sweat through the parts of their bodies that aren’t covered
in fur.
To keep cool, dogs lick their noses and pant.
Kangaroos do the same thing, they lick their forearms.
The extra heat they lose through the moisture cooling on their skin is usually enough to
regulate their body temperatures.
But when it gets unusually hot and there isn’t much rain, koalas would rather not lick themselves
or pant, because they’d get dehydrated too quickly.
And when you live in a tree, water can be hard to come by.
Climbing down to find water would expose them to predators, so they don’t want to do that.
In fact, koalas don’t normally drink very much; instead, they usually get all the water
they need from the eucalyptus leaves they eat.
By hugging trees, though, koalas can stay cool without losing water.
When researchers took infrared pictures of the koalas hugging trees, they realized that
the trees are, on average, about five degrees cooler than the surrounding air.
They’re not sure why the trees are so much cooler, but they think it might have something
to do with the groundwater the trees pull up through their trunks.
But it might also just take longer for the trees to heat up after the cool of the night.
By spreading as much of their bodies as possible against the trees, koalas are able to transfer
away some of their heat, and can cool themselves down by as much as 68 percent.
So yeah, hugging trees is adorable… also useful.
Thank you for watching this SciShow Quick Question, and especially thank you to 7-year-old
Zahava from Minnesota who suggested this topic.
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