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Rebecca O’Connell // Mariomassone via Wikimedia Commons, CC BY 2.0

Japanese Bears are Moving (and Conserving) Cherry Trees with Poop

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Rebecca O’Connell // Mariomassone via Wikimedia Commons, CC BY 2.0

We know Earth’s climate is changing rapidly, but we don’t fully know what those changes will mean for our planet and its inhabitants. Every organism interacts with those around it, making it hard to trace or predict the effects of pollution, species loss, and global warming. For example: a recent report published in the journal Current Biology shows that bears and their poop are slowly moving the cherry trees up mountains near Tokyo, Japan, and out of the damaging heat of lower altitudes. 

Plants, of course, don’t have legs (stick with us, this is going somewhere). Instead, they rely on the wind and on organisms with legs, wings, and fins to pollinate their flowers, eat their fruit, and carry the seeds to new locations

A team of Japanese researchers wondered how the behavior of these seed-dispersing animals might affect a plant’s ability to withstand climate change. They focused their study on the wild cherry tree (Prunus verecunda) for two reasons: first, botanists have predicted that the tree, which grows in temperate regions, will be especially vulnerable to rising temperatures; and second, the tree’s fruit are a favorite of local animals, especially the moon bear (Ursus thibetanus)

To track the plants’ movement, the scientists compared stable oxygen isotopes in their seeds. Every tree has these isotopes, which it gets from its parent tree while it’s still a seed. The isotope ratios vary by altitude, which makes them useful in geotagging. If a pooped-out seed on a mountain has a ratio associated with a lower altitude, it means the seed must have been carried up. (Unlike some species, P. verecunda seeds are exclusively dispersed by animals.) 

The researchers found that mountain-climbing bears brought cherry trees with them, often transporting seeds several hundred meters above their parent trees. The trees took root at new altitudes, in climates just slightly cooler than those down below. But this slight difference in temperature, around 3°F, might be enough to keep the trees safe. 

This is good news for the wild cherry; not all trees will be so lucky. P. verecunda happens to be a spring-fruiting tree, which means that bears stop and snack on its fruit on their journey up the mountain. The reverse would be true for autumn-fruiting trees: their seeds would be carried to lower, less tolerable altitudes. 

"The most important implication of our study on a warming planet is that seed dispersal direction can be asymmetric," lead author Shoji Naoe of the Forestry and Forest Products Research Institute said in a press statement. "Most previous studies have predicted future plant distributions under global warming based on the simple relationships between present plant distribution and environmental factors there, assuming that there are no seed dispersal limitations and no bias in dispersal direction. However, our study indicates that predicting future plant distributions can be very uncertain without considering the seed dispersal process that determines plant movement." 

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Big Questions
Why Do Cats Freak Out After Pooping?
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iStock

Cats often exhibit some very peculiar behavior, from getting into deadly combat situations with their own tail to pouncing on unsuspecting humans. Among their most curious habits: running from their litter box like a greyhound after moving their bowels. Are they running from their own fecal matter? Has waste elimination prompted a sense of euphoria?

Experts—if anyone is said to qualify as an expert in post-poop moods—aren’t exactly sure, but they’ve presented a number of entertaining theories. From a biological standpoint, some animal behaviorists suspect that a cat bolting after a deposit might stem from fears that a predator could track them based on the smell of their waste. But researchers are quick to note that they haven’t observed cats run from their BMs in the wild.

Biology also has a little bit to do with another theory, which postulates that cats used to getting their rear ends licked by their mother after defecating as kittens are showing off their independence by sprinting away, their butts having taken on self-cleaning properties in adulthood.

Not convinced? You might find another idea more plausible: Both humans and cats have a vagus nerve running from their brain stem. In both species, the nerve can be stimulated by defecation, leading to a pleasurable sensation and what some have labeled “poo-phoria,” or post-poop elation. In running, the cat may simply be working off excess energy brought on by stimulation of the nerve.

Less interesting is the notion that notoriously hygienic cats may simply want to shake off excess litter or fecal matter by running a 100-meter dash, or that a digestive problem has led to some discomfort they’re attempting to flee from. The fact is, so little research has been done in the field of pooping cat mania that there’s no universally accepted answer. Like so much of what makes cats tick, a definitive motivation will have to remain a mystery.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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Animals
Listen to the Impossibly Adorable Sounds of a Baby Sloth
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RODRIGO ARANGUA/AFP/GettyImages

Sometimes baby sloths seem almost too adorable to be real. But the little muppet-faced treasures don't just look cute—turns out they sound cute, too. We know what you're thinking: How could you have gone your whole life without knowing what these precious creatures sound like? Well, fear not: Just in time for International Sloth Day (today), we have some footage of how the tiny mammals express themselves—and it's a lot of squeaking. (Or maybe that's you squealing?)

The sloths featured in the heart-obliterating video below come from the Sloth Sanctuary of Costa Rica. The institution rescues orphaned sloths, rehabilitates them, and gets them ready to be released back into the wild.

[h/t The Kid Should See This]

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