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12 Awesome Spider Facts

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AMNH

Ask most people their opinion of spiders, and they’ll tell you that the arachnids are super creepy. And that might be kinda true, but the fact of the matter is, we need them as much as we need bees: Spiders are the dominant non-vertebrate predators in most exosystems, and without them, insect numbers would skyrocket. Human populations would also be much smaller—or even nonexistent—because the bugs would devour our crops, according to Norman Platnick, Curator Emeritus of the Division of Invertebrate Zoology at the American Museum of Natural History, and curator of Spiders Alive!, which opens tomorrow at the museum.

“It is a fact of reality that some of our visitors are likely to arrive with some fear of spiders, and I can understand that, to an extent,” he says. “I personally am afraid of snakes. But I regard that as a rational fear—about half of the snakes on this planet can actually hurt you. Being afraid of spiders is not rational in that sense. And so we hope to show why such arachnophobia is basically irrational, and that spiders are actually handsome, fascinating creatures that are extremely beneficial to humans.”

Platnick also hopes that visitors to the exhibition will come away with the knowledge that the study of spider diversity is an active field, with much to still be discovered. “Arachnologists have identified almost 45,000 different kinds of spiders at this point,” he says, “[but] that probably represents, at most, about half of the actual diversity of the group, and the numbers are growing very very quickly.”

Spiders Alive! showcases 16 spider species (plus two scorpions and a vinegaroon!) and features live demonstrations and a model of a trap door spider that's 50 times life size—and you can climb on it! Here are a few things we learned from an early visit.

1. Brown recluse venom destroys human tissue, but it has very little effect on rats and mice. Rabbits, meanwhile, are super sensitive: They can develop a wound from as little as 15 micrograms of venom.

2. Spider fossils are hard to find because the animals’ exoskeletons are relatively soft. For every 1000 insect fossils discovered, there’s only one spider.

3. We think of spiders as solitary creatures, but some 20 species work together to survive—including the African funnel-web spider, which shares its web with hundreds of its brethren.

4. This trick is not for the arachnophobic: If you’re walking around at night and want to find any wolf spiders that might be around, use a flashlight—their eyes will reflect the light back at you, like a less cute cat.

5. Tarantulas get their common name from an illness that swept through Taranto, Italy, in medieval times; people thought the illness was caused by the bite of a large-but-harmless spider. To be cured, the afflicted would do a dance called “tarantella” until they were completely exhausted. That poor spider became so well-known that when people settled in the New World, they called any large, hairy spider they came across a tarantula.

Photo by Erin McCarthy

6. Many tarantulas in North and South America defend themselves by using their hind legs to kick off the urticating hairs on their abdomens. The hairs are sharp and irritating, and become embedded in a predator’s skin, eyes, and respiratory tract, hopefully giving the spider time to get away. How can you tell if a tarantula has been using its hairs? Look for a tell-tale bald spot on its abdomen.

7. Despite its name, the Goliath bird eater only rarely eats birds! Instead, this spider—one of the biggest in the world—more often dines on snakes, mice, and frogs.

8. Not all spiders build webs, but all spiders make silk; it emerges from flexible spinnerets, which can be lifted, lowered, and twisted and, in some cases, moved independently, allowing the spider to direct the flow of the silk without moving its whole body. Some use silk to protect their eggs, sail through the air, or get a mate; one species, Argyroneta aquatica, even uses it to survive underwater! The spider builds a dome-shaped web with its silk and stores air bubbles there that it has collected on trips to the surface. It can stay underwater for as long as a day before having to return to the surface.

9. We’ve used spider silk for some pretty incredible things: In the 1800s, travelers saw Solomon Islanders using fishnets made of the material, and in 1943, the U.S. Army used silk from the black widow spider to make crosshairs on sighting devices. More recently, scientists used spider silk as a scaffold for growing human skin cells.

10. Orb webs have three parts: the frame, or foundation, which is the first thing a spider builds; the radii, which come out from the center like the spokes of a bicycle and transmit vibrations from prey; and the catching spiral, the sticky part of the web, which can stretch without breaking, making it hard for insects to escape. Some spiders take their webs down often—even daily!

11. Charlotte A. Cavatica from Charlotte’s Web is named after a common orb weaver, Araneus cavaticus. White consulted an expert at AMNH for help when researching the book.

Photo by Erin McCarthy

12. With well over 1 million specimens, AMNH has the largest research collection of spiders in the world. Unlike insects, which are typically pinned, the arachnids are stored in alcohol so they don’t dry out, which would render the specimens useless.

AND, JUST BECAUSE ... BONUS GIANT VINEGAROON PHOTO!

Disturb one of these arachnids, and they'll shoot a foul smelling spray at you from their abdomens. Don't say we didn't warn you!

All photos courtesy of AMNH unless otherwise noted.

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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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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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