5 Crazy Things That Spiders Eat


If you thought spiders only eat insects, think again. In recent years, scientists have discovered that small animals and other surprising food items are an important part of many spiders’ diets.   

1. Fish

Semiaquatic spiders such as Dolomedes facetus (above) occasionally kill and devour small fish, according to a new study in PLoS One. The study’s authors list more than 80 known cases, spread across every continent except Antarctica, where spiders have ambushed fish from the edges of ponds, lakes, rivers and swamps. The arachnids use their neurotoxic venom to subdue the fish, then drag them to a dry place to eat them. The chum are small—typically between one and 2.5 inches long—but on average they’re 2.2 times larger than the spider.

One interesting species, Argyroneta aquatica, constructs a dome-shaped web amongst water plants, and fills it with air from the surface. After the spider slays its aquatic prey, it brings the meal back to the dome to eat it.

2. Bats

Scientists have reported more than 52 cases of spiders eating small or juvenile bats with a wingspan of up to nine inches. In the majority of those cases, the bats accidentally get tangled up in webs—usually those of tropical and subtropical orb-weaving spiders, whose webs can be six feet in diameter or larger. But some species of tarantula have been known to stalk and attack bats on rare occasions.

3. Birds

There’s no indication that spiders are adapted to eat birds. In fact, a collision with a bird can cause significant damage to a spider’s web. But when life hands you lemons … wrap them in silk, liquefy their innards, and feast.

A 2012 paper catalogued 69 cases of birds getting trapped in spider webs, including 18 that had been mummified in silk for consumption by the spiders. (Many of these birds were rescued through human intervention.) The largest species recorded was a three-ounce Laughing Dove. Most of the other victims were hummingbirds. Here again, the culprits were almost always orb weaver spiders.

4. Snakes

Dinesh Rao/Flickr

That’s right—spiders can eat snakes. And if you don’t believe us, check out this horrifying video, or these images. In 1926, Canadian entomologist James Henry Emerton wrote a graphic description of how the tarantula Grammostola actaeon kills its slithering prey:

When a Grammostola and a young snake are put in a cage together the spider tries to catch the snake by the head and will hold on in spite of all efforts of the snake to shake him off. After a minute or two the spider's poison takes effect, and the snake become quiet. Beginning at the head, the spider crushes the snake with its mandibles and feeds upon its soft parts, some- times taking 24 hours or more to suck the whole animal, leaving the remains in a shapeless mass.

5. Plants

R. L. Curry

Of the world’s 35,000 or so spider species, only one is known to be herbivorous. The (mostly) vegetarian Bagheera kiplingi dines on leaf tips of the acacia shrub in Mexico and Central America. It uses its hunting kills to avoid the ants that colonize acacia … and occasionally dines on their larvae to supplement its diet.

Why Tiny 'Hedgehog Highways' Are Popping Up Around London

Hedgehogs as pets have gained popularity in recent years, but in many parts of the world, they're still wild animals. That includes London, where close to a million of the creatures roam streets, parks, and gardens, seeking out wood and vegetation to take refuge in. Now, Atlas Obscura reports that animal activists are transforming the city into a more hospitable environment for hedgehogs.

Barnes Hedgehogs, a group founded by Michel Birkenwald in the London neighborhood of Barnes four years ago, is responsible for drilling tiny "hedgehog highways" through walls around London. The passages are just wide enough for the animals to climb through, making it easier for them to travel from one green space to the next.

London's wild hedgehog population has seen a sharp decline in recent decades. Though it's hard to pin down accurate numbers for the elusive animals, surveys have shown that the British population has dwindled by tens of millions since the 1950s. This is due to factors like human development and habitat destruction by farmers who aren't fond of the unattractive shrubs, hedges, and dead wood that hedgehogs use as their homes.

When such environments are left to grow, they can still be hard for hedgehogs to access. Carving hedgehog highways through the stone partitions and wooden fences bordering parks and gardens is one way Barnes Hedgehogs is making life in the big city a little easier for its most prickly residents.

[h/t Atlas Obscura]

Penn Vet Working Dog Center
Stones, Bones, and Wrecks
New Program Trains Dogs to Sniff Out Art Smugglers
Penn Vet Working Dog Center
Penn Vet Working Dog Center

Soon, the dogs you see sniffing out contraband at airports may not be searching for drugs or smuggled Spanish ham. They might be looking for stolen treasures.

K-9 Artifact Finders, a new collaboration between New Hampshire-based cultural heritage law firm Red Arch and the University of Pennsylvania, is training dogs to root out stolen antiquities looted from archaeological sites and museums. The dogs would be stopping them at borders before the items can be sold elsewhere on the black market.

The illegal antiquities trade nets more than $3 billion per year around the world, and trafficking hits countries dealing with ongoing conflict, like Syria and Iraq today, particularly hard. By one estimate, around half a million artifacts were stolen from museums and archaeological sites throughout Iraq between 2003 and 2005 alone. (Famously, the craft-supply chain Hobby Lobby was fined $3 million in 2017 for buying thousands of ancient artifacts looted from Iraq.) In Syria, the Islamic State has been known to loot and sell ancient artifacts including statues, jewelry, and art to fund its operations.

But the problem spans across the world. Between 2007 and 2016, U.S. Customs and Border Control discovered more than 7800 cultural artifacts in the U.S. looted from 30 different countries.

A yellow Lab sniffs a metal cage designed to train dogs on scent detection.
Penn Vet Working Dog Center

K-9 Artifact Finders is the brainchild of Rick St. Hilaire, the executive director of Red Arch. His non-profit firm researches cultural heritage property law and preservation policy, including studying archaeological site looting and antiquities trafficking. Back in 2015, St. Hilaire was reading an article about a working dog trained to sniff out electronics that was able to find USB drives, SD cards, and other data storage devices. He wondered, if dogs could be trained to identify the scents of inorganic materials that make up electronics, could they be trained to sniff out ancient pottery?

To find out, St. Hilaire tells Mental Floss, he contacted the Penn Vet Working Dog Center, a research and training center for detection dogs. In December 2017, Red Arch, the Working Dog Center, and the Penn Museum (which is providing the artifacts to train the dogs) launched K-9 Artifact Finders, and in late January 2018, the five dogs selected for the project began their training, starting with learning the distinct smell of ancient pottery.

“Our theory is, it is a porous material that’s going to have a lot more odor than, say, a metal,” says Cindy Otto, the executive director of the Penn Vet Working Dog Center and the project’s principal investigator.

As you might imagine, museum curators may not be keen on exposing fragile ancient materials to four Labrador retrievers and a German shepherd, and the Working Dog Center didn’t want to take any risks with the Penn Museum’s priceless artifacts. So instead of letting the dogs have free rein to sniff the materials themselves, the project is using cotton balls. The researchers seal the artifacts (broken shards of Syrian pottery) in airtight bags with a cotton ball for 72 hours, then ask the dogs to find the cotton balls in the lab. They’re being trained to disregard the smell of the cotton ball itself, the smell of the bag it was stored in, and ideally, the smell of modern-day pottery, eventually being able to zero in on the smell that distinguishes ancient pottery specifically.

A dog looks out over the metal "pinhweel" training mechanism.
Penn Vet Working Dog Center

“The dogs are responding well,” Otto tells Mental Floss, explaining that the training program is at the stage of "exposing them to the odor and having them recognize it.”

The dogs involved in the project were chosen for their calm-but-curious demeanors and sensitive noses (one also works as a drug-detection dog when she’s not training on pottery). They had to be motivated enough to want to hunt down the cotton balls, but not aggressive or easily distracted.

Right now, the dogs train three days a week, and will continue to work on their pottery-detection skills for the first stage of the project, which the researchers expect will last for the next nine months. Depending on how the first phase of the training goes, the researchers hope to be able to then take the dogs out into the field to see if they can find the odor of ancient pottery in real-life situations, like in suitcases, rather than in a laboratory setting. Eventually, they also hope to train the dogs on other types of objects, and perhaps even pinpoint the chemical signatures that make artifacts smell distinct.

Pottery-sniffing dogs won’t be showing up at airport customs or on shipping docks soon, but one day, they could be as common as drug-sniffing canines. If dogs can detect low blood sugar or find a tiny USB drive hidden in a house, surely they can figure out if you’re smuggling a sculpture made thousands of years ago in your suitcase.


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