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  • [♪ INTRO]

  • If you give a pile of fresh horse poop to a pandawell, it'll probably give you a funny look.

  • Unless it's cold out, that is.

  • If it's chilly enough, the panda might start to roll around in the poop and smear it all over itself.

  • It's not because the poop is warmbut it does help pandas manage chilly temperatures in another way.

  • Over the course of about ten years, Chinese researchers studying the behavior of wild

  • giant pandas noticed this weird poop-bathing behavior.

  • It seemed to be specific to horse poop.

  • The scientists described the pandas as smearing horse manure over their entire bodies.

  • Now, this raises an obvious question: Uh, why

  • Well, the  inevitable march of science being what it is, researchers decided to find out.

  • And in 2020, they reported that they'd finally solved the mystery.

  • Their observations showed a strong connection with temperature.

  • Basically, pandas only do this when temperatures drop below 15 degrees.

  • That provided one clue: the poop-smearing habit had something to do with the cold.

  • A second clue was that the poop generally had to be less than 10 days old for it to

  • be appealing to the pandas.

  • It did not have to be steaming hot. Just relatively fresh.

  • That gave the scientists the hint they needed to start looking at volatile compounds.

  • These are chemicals that waft into the air and are often responsible for scents.

  • In this case, the smell of horse poop.

  • Their search eventually led them to two chemical compounds, beta-caryophyllene and caryophyllene oxide.

  • These are members of a group of chemicals called terpenes, which are often found in plants.

  •   Beta-caryophyllene is what gives pepper its

  • pepperiness, and caryophyllene oxide is found in plants like lemon balm and eucalyptus.

  •   I know, that's probably not what you imagine

  • when you think of the smell of horse poop.

  • But these compounds were wafting abundantly from the relatively fresh poop that the pandas preferred.

  • Older manure had less of them.

  •   And when the researchers tried sprinkling

  • these compounds on hay and giving it to zoo pandas, they rolled around in it, just like their wild cousins did with the poop!

  •   So what's the deal?

  • Well, it turns out that these chemicals mess with our bodies' cold sensors.

  •   In the study, the researchers demonstrated

  • that mice given the compounds were less sensitive to the cold.

  •   Plus, they discovered that these compounds

  • inhibit pandas' TRPM8 receptors, the major player in how our bodies sense cold.

  • These proteins react to temperature and let your brain know that you're coming into contact with something cold.

  • But there are ways of tricking these receptors.

  • Menthol activates them, for example, which is why mints can make your mouth feel cool.

  • And it turns out that the terpenes in fresh horse poop have the opposite effect, keeping

  • pandas' TRPM8 receptors from working properly.

  • So basically, by rolling in horse poop, the pandas are probably dulling the sting of the cold.

  • It almost makes you wonder why other animals haven't discovered the wondrous warming powers of horse manure.

  • Then againmaybe they're just sensible enough to look for other ways to stay warm.

  • And now, because every sponsor wants to be mentioned in the same breath as poop, let's talk about Brilliant.

  • Brilliant's daily challenges will help you get just that little bit smarter on the regular,

  • and practice the reasoning skills that scientists needed when they asked whether pandas might

  • have a good reason for rolling in dung.

  • Each challenge also ties into a whole interactive course if you want to learn more.

  • You can get started at, with the chance to save 20% on an annual premium subscription.

  • And thank you for your support!

  • [♪ OUTRO]

Thanks to Brilliant for supporting this episode of SciShow.


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B2 中高級 美國腔

Why Pandas LOVE Rolling in Horse Manure

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    Miho Ishii 發佈於 2021 年 02 月 24 日