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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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Animals
Where Do Birds Get Their Songs?
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iStock

Birds display some of the most impressive vocal abilities in the animal kingdom. They can be heard across great distances, mimic human speech, and even sing using distinct dialects and syntax. The most complex songs take some practice to learn, but as TED-Ed explains, the urge to sing is woven into songbirds' DNA.

Like humans, baby birds learn to communicate from their parents. Adult zebra finches will even speak in the equivalent of "baby talk" when teaching chicks their songs. After hearing the same expressions repeated so many times and trying them out firsthand, the offspring are able to use the same songs as adults.

But nurture isn't the only factor driving this behavior. Even when they grow up without any parents teaching them how to vocalize, birds will start singing on their own. These innate songs are less refined than the ones that are taught, but when they're passed down through multiple generations and shaped over time, they start to sound similar to the learned songs sung by other members of their species.

This suggests that the drive to sing as well as the specific structures of the songs themselves have been ingrained in the animals' genetic code by evolution. You can watch the full story from TED-Ed below, then head over here for a sample of the diverse songs produced by birds.

[h/t TED-Ed]

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Animals
Watch the First-Ever Footage of a Baby Dumbo Octopus
NOAA, Wikimedia Commons // Public Domain
NOAA, Wikimedia Commons // Public Domain

Dumbo octopuses are named for the elephant-ear-like fins they use to navigate the deep sea, but until recently, when and how they developed those floppy appendages were a mystery. Now, for the first time, researchers have caught a newborn Dumbo octopus on tape. As reported in the journal Current Biology, they discovered that the creatures are equipped with the fins from the moment they hatch.

Study co-author Tim Shank, a researcher at the Woods Hole Oceanographic Institution in Massachusetts, spotted the octopus in 2005. During a research expedition in the North Atlantic, one of the remotely operated vehicles he was working with collected several coral branches with something strange attached to them. It looked like a bunch of sandy-colored golf balls at first, but then he realized it was an egg sac.

He and his fellow researchers eventually classified the hatchling that emerged as a member of the genus Grimpoteuthis. In other words, it was a Dumbo octopus, though they couldn't determine the exact species. But you wouldn't need a biology degree to spot its resemblance to Disney's famous elephant, as you can see in the video below.

The octopus hatched with a set of functional fins that allowed it to swim around and hunt right away, and an MRI scan revealed fully-developed internal organs and a complex nervous system. As the researchers wrote in their study, Dumbo octopuses enter the world as "competent juveniles" ready to jump straight into adult life.

Grimpoteuthis spends its life in the deep ocean, which makes it difficult to study. Scientists hope the newly-reported findings will make it easier to identify Grimpoteuthis eggs and hatchlings for future research.

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