10 of the World's Strangest Spiders

Wirepec // iStock
Wirepec // iStock

All spiders have eight legs, but that’s where most of their similarities end. Scientists frequently discover new species with unexpected talents—be it a flair for cartwheels or the ability to turn itself into a disco ball. Researchers have also found plenty of specimens that are just plain weird-looking. Here’s a list of 10 fascinatingly freaky arachnids.

1. CEBRENNUS RECHENBERGI // THE FLIC-FLAC SPIDER

A native of the Erg Chebbi desert in southeastern Morocco, Cebrennus rechenbergi—also known as the flic-flac spider—has the remarkable ability to cartwheel its way out of danger. When threatened by a predator, it will leap off the ground and do a series of high-energy somersaults to make a quick exit. An alarmed flic-flac spider can tumble forward at a rate of 6.6 feet per second—twice as fast as its maximum walking speed. If pressed, it can even cartwheel uphill. Such talents did not go unappreciated by this spider’s discoverer, bionics expert Ingo Rechenberg, who has built a somersaulting robot based on the flic-flac’s locomotion.

2. BAGHEERA KIPLINGI // A JUMPING SPIDER

Bagheera kiplingi spider
Maximilian Paradiz // Wikimeda Commons // CC BY 2.0

Those who have read Rudyard Kipling’s The Jungle Book may have already figured out that this species was named after the panther who helps raise Mowgli. But its pop culture connection is not Bagheera kiplingi’s only claim to fame. It has a plant-based diet, unlike nearly all other spiders, which subsist predominantly on meat. B. kiplingi feasts on the nutritious nubs of Central American acacias, which the trees produce to feed their colonies of guard ants. The ants protect the trees from predators, but the spiders have learned how to swoop in and steal the nubs without providing any symbiotic benefit. The spiders will also eat nectar and ant larvae, and when times are tough, they’ve been known to practice cannibalism.

3. ARACHNURA HIGGINSI // THE SCORPION-TAILED SPIDER

Arachnura higginsi spider
Peter Woodard // Wikimedia Commons // Public Domain

Two phobias for the price of one! Found only in Australia, the scorpion-tailed spider is so named because adult females have a long, thin appendage on the tip of their abdomens. (Males and juveniles lack this structure.) The females can arch this bendable tail over their backsides, which gives them the appearance of irate scorpions and prompts would-be attackers to keep their distance. But it’s all an act: The tail cannot sting and Arachnura higginsi is mostly harmless to humans.

4. CAEROSTRIS DARWINI // DARWIN’S BARK SPIDER

The male Darwin’s bark spider is eager to please. Really, really eager. The diminutive males exhibit what some scientists have called “a rich sexual repertoire” to their much larger mates. During sex, males nibble on their partners’ genitals or immobilize them with a web of silk before getting busy. Males will also detach their own sexual organs inside their mates to prevent females from mating with others. Researchers muse that this unusual behavior grew out of males’ survival instinct: A female Darwin’s bark spider is liable to eat her partner after mating.

5. GENUS SCYTODES // SPITTING SPIDERS

Scytodes thoracica spider
Fritz Geller-Grimm // Wikimedia Commons // CC BY-SA 3.0

Using webs to catch prey is all well and good, but it almost seems tame compared to what spitting spiders do to their victims. To subdue a target, the killers take aim and fire twin streams of venom-drenched silk out of their fangs. At a top speed of 62 miles per hour, the fibers move in a wide-arced, zig-zag pattern. In addition to being coated with poison, this silk drips with a super-sticky glue. Once victims are enmeshed, the glue-covered fibers will shrink, constricting the unfortunate prey. Eventually, the spitting spider will administer a venomous bite and put the trapped entrée out of its misery.

6. GENUS DOLOMEDES // FISHING SPIDERS

Hydrophobic coats and a knack for exploiting surface tension allow these predators to walk on water. Fishing spiders lurk in North America, Europe, Australia, and New Zealand. To hunt tadpoles, aquatic insects, and even small fish, many species of fishing spiders will splay themselves over the surface of freshwater lakes or streams. Then, using hundreds of ultra-sensitive leg hairs, they monitor aquatic vibrations. When prey swims by, the spider homes in on its precise location and dives for the victim, sometimes as much as 18 centimeters below the water’s surface.

7. CYRTARACHNE INAEQUALIS // A “DISCO SPIDER”

This little fellow—which arachnologist Joseph Koh believes is Cyrtarachne inaequalis, a member of the Cyrtarachne orb-weaver spider genus—made a vivid impression on photographer Nicky Bay, who captured its singular light show on film. The orb-weaver’s abdomen exhibits a pulsating movement that appear to show its internal organs working under a translucent membrane, Bay writes. Scientists have suggested that the spiders’ display attracts prey or scares off predators, but how and why C. inaequalis puts on its tiny disco act remains a mystery.

8. GENUS MYRMARACHNE // ANT-MIMICKING JUMPING SPIDERS

Myrmarachne ant spider

Found in tropical and temperate zones all over the world, Myrmarachne spiders pretend to be ants—which predators view as aggressive and not worth the effort—to stay alive. With their elongated heads and hourglass-shaped thoraxes, the arachnids look a lot like various ant species (their Latin name even means “ant-spider”). To help sell the illusion, they’ll wiggle their front legs like an ant’s writhing antennae. Of course, a good actor knows when to break character. If certain Myrmarachne species come across predators that eat ants, they’ll drop the ruse.

9. SUPERFAMILY PALPIMANOIDEA // ASSASSIN SPIDERS

Assassin spiders are so named because most of them eat smaller, sometimes poisonous spiders. To keep their food from biting back, Palpimanoidea have evolved long, skinny, giraffe-like necks. Their tiny heads sport huge sets of jaws. When an assassin spider finds a meal, those jaws impale the target and swing forward at a 90-degree angle. That keeps victims a safe distance away from any of the assassin spider’s sensitive body parts. Before long, the skewered prey will die on one of the distended jaws. Then the feasting can begin.

10. GENUS SELENOPS // SPIDERS THAT GLIDE

Our planet is home to more than 40,000 different kinds of spiders, and luckily for arachnophobes, none of them can fly. But at least one genus can free-fall like champion parachutists. In a 2015 study, biologists documented this unusual behavior by systematically dropping 59 tree-dwelling spiders of the genus Selenops from “either canopy platforms or tree crowns in Panama and Peru.” Ninety-three percent of these arachnids steered themselves towards nearby trees to land safely on the trunks. The researchers speculate that such gliding descents happen all the time in nature. After all, the spiders predominantly reside in trees—and the ability to parachute from one trunk to the next would be a huge asset.

Do Dogs Understand What You’re Telling Them? Scientists Are Scanning Their Brains to Find Out

iStock/kozorog
iStock/kozorog

We all know that dogs can learn to respond to human words, but it’s not always clear what’s happening in a dog’s brain when they hear and recognize words like “cookie” and “fetch.” Do they have to rely on other clues, like gestures, to figure out what we mean by that word? Do they picture a dog biscuit when you say “cookie,” or just the sensation of eating? In a new study, scientists from Emory University and the New College of Florida tried to get to the bottom of this question by training dogs to associate certain objects with words like “blue” and “duck,” then using fMRI brain scanners to see what was happening in the dogs’ heads when they heard that word.

The study, published in Frontiers in Neuroscience, examined the brains of 12 different dogs of various breeds (you can see them below) that had been trained to associate two different objects with random words like “duck,” “blue,” and “beach ball.” Those two objects, which were different for each dog, were brought by the dogs’ owners from home or chosen from a selection of dog toys the researchers compiled. One object had to be soft, like a stuffed animal, and the other one had to be something hard, like a rubber toy or squeaky toy, to make sure the dogs could clearly distinguish between the two. The dogs were trained for several months to associate these objects with their specific assigned words and to fetch them on command.

Then, they went into the fMRI machine, where they had been trained to sit quietly during scanning. The researchers had the dogs lie in the machine while their owners stood in front of them, saying the designated name for the toys and showing them the objects. To see how the dogs responded to unknown words, they also held up new objects, like a hat, and referred to them by gibberish words.

Dogs in a science lab with toys
Prichard et al., Frontiers in Neuroscience (2018]

The results suggest that dogs can, in fact, discriminate between words they know and novel words. While not all the dogs showed the same neural response, they showed activation in different regions of their brains when hearing the familiar word versus the novel one.

Some of the dogs showed evidence of a greater neural response in the parietotemporal cortex, an area of the dog brain believed to be similar to the human angular gyrus, the region of the brain that allows us to process the words we hear and read. Others showed more neural activity in other regions of the brain. These differences might be due to the fact that the study used dogs of different sizes and breeds, which could mean differences in their abilities.

The dogs did show a surprising trend in their brains’ response to new words. “We expected to see that dogs neurally discriminate between words that they know and words that they don’t,” lead author Ashley Prichard of Emory University said in a press release. “What's surprising is that the result is opposite to that of research on humans—people typically show greater neural activation for known words than novel words." This could be because the dogs were trying extra hard to understand what their owners were saying.

The results don’t prove that talking to your dog is the best way to get its attention, though—it just means that they may really know what's coming when you say, "Want a cookie?"

Scientists Find Fossil of 150-Million-Year-Old Flesh-Eating Fish—Plus a Few of Its Prey

M. Ebert and T. Nohl
M. Ebert and T. Nohl

A fossil of an unusual piranha-like fish from the Late Jurassic period has been unearthed by scientists in southern Germany, Australian news outlet the ABC reports. Even more remarkable than the fossil’s age—150 million years old—is the fact that the limestone deposit also contains some of the fish’s victims.

Fish with chunks missing from their fins were found near the predator fish, which has been named Piranhamesodon pinnatomus. Aside from the predator’s razor-sharp teeth, though, it doesn’t look like your usual flesh-eating fish. It belonged to an extinct order of bony fish that lived at the time of the dinosaurs, and until now, scientists didn’t realize there was a species of bony fish that tore into its prey in such a way. This makes it the first flesh-eating bony fish on record, long predating the piranha. 

“Fish as we know them, bony fishes, just did not bite flesh of other fishes at that time,” Dr. Martina Kölbl-Ebert, the paleontologist who found the fish with her husband, Martin Ebert, said in a statement. “Sharks have been able to bite out chunks of flesh, but throughout history bony fishes have either fed on invertebrates or largely swallowed their prey whole. Biting chunks of flesh or fins was something that came much later."

Kölbl-Ebert, the director of the Jura Museum in Eichstätt, Germany, says she was stunned to see the bony fish’s sharp teeth, comparing it to “finding a sheep with a snarl like a wolf.” This cunning disguise made the fish a fearful predator, and scientists believe the fish may have “exploited aggressive mimicry” to ambush unsuspecting fish.

The fossil was discovered in 2016 in southern Germany, but the find has only recently been described in the journal Current Biology. It was found at a quarry where other fossils, like those of the Archaeopteryx dinosaur, have been unearthed in the past.

[h/t the ABC]

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