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Tiny Plastics in the Ocean Are Harming Baby Fish

Plastic pollution in our world’s oceans might carry more dire consequences than we initially realized. According to a new study published in the journal Science, some baby fish like to chow down on plastic microparticles instead of natural foods like free-swimming zooplankton. In turn, this unnatural diet leads to stunted growth, changed behavior, and, ultimately, increased mortality rates, the BBC reports.

Researchers from Uppsala University in Sweden collected fertilized European perch eggs and embryos from the Baltic Sea. They then exposed them to different concentrations of polystyrene plastic microparticles that were smaller than one-fifth of an inch, around the size of ones floating in the sea.

When the eggs weren’t exposed to microplastics, 96 percent of them hatched. But when they were exposed to high concentrations of the plastics, the amount dropped to 81 percent. Meanwhile, the surviving fish that had been exposed to the plastic were reportedly “smaller, slower, and more stupid,” the study’s lead author, Oona Lönnstedt, told the BBC.

The fish also didn’t fare well against predators as their olfactory responses were impaired. Within 24 hours, larger fish like pike had gobbled up all the fish that had been raised with high plastic concentrations. In comparison, half the fish from clean waters survived.

Perhaps most strikingly, fish larvae that had access to the plastic particles preferred to eat them instead of zooplankton. “This is the first time an animal has been found to preferentially feed on plastic particles and is cause for concern,” Peter Eklöv, the study’s co-author, said in a press statement.

Researchers plan to research the perch in their natural setting, and study how exposure to other plastic contaminants affects development. “Now we know that polystyrene is harmful, but we also need to compare it to the other common polymers such as polyethylene and PVC,” Lönnstedt told PBS NewsHour. “If we can target the chemical that is most harmful, at least this could hopefully be phased out of production.”

While President Obama signed a ban on plastic microbeads last year, some 13 million tons of plastic reportedly flows into the sea each year, and experts say that amount will only increase. Meanwhile, according to PBS NewsHour, up to 236,000 metric tons of microplastics enter the oceans each year thanks to larger pieces of plastic breaking down into little pieces.

[h/t BBC News]

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Big Questions
Why Do Cats Freak Out After Pooping?
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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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