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Slow, but Scary, Killer Snails


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The killers in some classic slasher movies are notoriously slow. Jason Voorhees, Michael Myers, and Leatherface all shamble along at a pace that makes little old ladies look like Usain Bolt. It’s got to be frustrating for someone with murder on their mind to get outrun by their victims. But real-world slow-and-scaries, the predatory cone snails of the genus Conus, have evolved a frightening way to make up for their speed deficit: venomous, harpoon-like teeth that can stab prey and drag them to the snail.

The snails bury themselves in the sand and lie in wait or sneak up on their prey, using a specialized chemical-sensory organ to detect a meal. Once a victim is in range, the snail strikes. It points its long, flexible proboscis at its victim and launches a modified radular tooth—hollow, barbed and made of chitin—from it. The tooth is loaded with a cocktail of neurotoxins that reduce pain to pacify the prey and quickly paralyze it by blocking neurotransmitter receptors. The tooth is still attached to the radula structure, so once the prey is subdued, the snail draws both the tooth and its dinner right into its mouth. After the meal has been processed, the snail pukes up any leftover indigestible bits along with the used tooth, and readies another one to fire. You can see the a snail do the jab-and-grab and then swallow a fish whole in this National Geographic video.

The snail’s venom gland and the toxins it makes have fascinated scientists for more than a century. A researcher from Canada’s University of Victoria recently discovered that the venom glands of the species C. lividus come from a bit of “epithelial [tissue] remodeling” and are formed when a part of the esophagus pinches off as the snail transitions into adulthood. The researcher suggests that this tissue tweaking process allowed the snail to develop its weaponry and become carnivorous in a relatively short evolutionary timeframe.

Meanwhile, the speed and precision of the snails’ venom have led other researchers to look into it for medical use as a painkiller with few or no side effects. One painkiller derived from the snails’ arsenal has already been approved by the FDA. “Prialt” contains ziconotide, a synthetic equivalent of one of the snails’ many toxins, and is approved for use in treating chronic pain in patients with cancer and AIDS. Dozens of other cone snail toxins are still being investigated for use in pain relief and treating epilepsy, cardiovascular disease, Alzheimer’s, Parkinson’s, and other diseases and disorders.

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Animals
How a Pregnant Rhino Named Victoria Could Save an Entire Subspecies
Sudan, the last male member of the northern white rhino subspecies, while being shipped to Kenya in 2009
Sudan, the last male member of the northern white rhino subspecies, while being shipped to Kenya in 2009
Tony Karumba, AFP/Getty Images

The last male northern white rhino died at a conservancy in Kenya earlier this year, prompting fears that the subspecies was finally done for after decades of heavy poaching. Scientists say there's still hope, though, and they're banking on a pregnant rhino named Victoria at the San Diego Zoo, according to the Associated Press.

Victoria is actually a southern white rhino, but the two subspecies are related. Only two northern white rhinos survive, but neither of the females in Kenya are able to reproduce. Victoria was successfully impregnated through artificial insemination, and if she successfully carries her calf to term in 16 to 18 months, scientists say she might be able to serve as a surrogate mother and propagate the northern white rhino species.

But how would that work if no male northern rhinos survive? As the AP explains, scientists are working to recreate northern white rhino embryos using genetic technology. The San Diego Zoo Institute for Conservation Research has the frozen cell lines of 12 different northern white rhinos, which can be transformed into stem cells—and ultimately, sperm and eggs. The sperm of the last northern white male rhino, Sudan, was also saved before he died.

Scientists have been monitoring six female southern white rhinos at the San Diego Zoo to see if any emerge as likely candidates for surrogacy. However, it's not easy to artificially inseminate a rhino, and there have been few successful births in the past. There's still a fighting chance, though, and scientists ultimately hope they'll be able to build up a herd of five to 15 northern white rhinos over the next few decades.

[h/t Time Magazine]

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entertainment
Why Our Brains Love Plot Twists
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From the father-son reveal in The Empire Strikes Back to the shocking realization at the end of The Sixth Sense, everyone loves a good plot twist. It's not the element of surprise that makes them so enjoyable, though. It's largely the set-up, according to cognitive scientist Vera Tobin.

Tobin, a researcher at Case Western Reserve University, writes for The Conversationthat one of the most enjoyable moments of a film or novel comes after the big reveal, when we get to go back and look at the clues we may have missed. "The most satisfying surprises get their power from giving us a fresh, better way of making sense of the material that came before," Tobin writes. "This is another opportunity for stories to turn the curse of knowledge to their advantage."

The curse of knowledge, Tobin explains, refers to a psychological effect in which knowledge affects our perception and "trips us up in a lot of ways." For instance, a puzzle always seems easier than it really is after we've learned how to solve it, and once we know which team won a baseball game, we tend to overestimate how likely that particular outcome was.

Good writers know this intuitively and use it to their advantage to craft narratives that will make audiences want to review key points of the story. The end of The Sixth Sense, for example, replays earlier scenes of the movie to clue viewers in to the fact that Bruce Willis's character has been dead the whole time—a fact which seems all too obvious in hindsight, thanks to the curse of knowledge.

This is also why writers often incorporate red herrings—or false clues—into their works. In light of this evidence, movie spoilers don't seem so terrible after all. According to one study, even when the plot twist is known in advance, viewers still experience suspense. Indeed, several studies have shown that spoilers can even enhance enjoyment because they improve "fluency," or a viewer's ability to process and understand the story.

Still, spoilers are pretty universally hated—the Russo brothers even distributed fake drafts of Avengers: Infinity War to prevent key plot points from being leaked—so it's probably best not to go shouting the end of this summer's big blockbuster before your friends have seen it.

[h/t The Conversation]

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