Mining spiders have exploded in popularity recently, as many are realizing for the first time that some of the most impressive arachnids in the world live their entire lives in dark and remote places. While there isn’t just one genus of cave-dwelling arachnids, there are a host of impressive spiders to be found in caves and mines – and they certainly only get more attractive when humans abandon them.
Perhaps the most impressive mining spider is a species first identified in an abandoned mine in Mexico’s Baja California Sur. In a pretty creepy way, its existence was first suggested by the discovery of a hollow shell.
Mining spiders: find a monster
“The first evidence we found of this species was a shed exoskeleton in the crevices of an overhanging rock,” said Jim Berrian, a field tomologist at the San Diego Natural History Museum and one of the authors describing the new species in a statement.
“The exoskeleton was abnormally large and I could tell from the eye pattern that it was in a group of spiders, wandering spiders from the family Ctenidaewith very few species in Baja California Sur.”
The colossus of mining spiders was not only a new species, but also a new genus. It was called the Sierra Cacachilas wandering spider, Califorctenus cacachilensisand is a relative of the notoriously venomous Brazilian wandering spider, Phoneutria fera.
The Brazilian wandering spider certainly looks very Shelob, but it likes the rainforest more than a mine.
Image credit: Margus Vilbas Photography/Shutterstock.com
Fortunately for Berrian, it doesn’t appear that the Sierra Cacachilas inherited the same toxicity.
“I was bitten while handling a live specimen of Califorctenus cacachilensis and I’m still alive,” he added. “We have not analyzed the toxicity of the venom, but most wandering spiders are not as dangerous as the Brazilian wandering spider.”
The mother of all mining spiders
What it lacks in venom power it makes up for in size. With spindly legs about 10 centimeters (4 inches) long and a short, stocky body measuring 2.5 centimeters (one inch), its spread size is about that of a basketball. It’s a body plan that makes spinning a web pointless, it’s much better to run along the walls of abandoned mines and hunt for your prey on foot. Their venom may not be strong enough to incapacitate Berrian, but it would make short work of anything the size of a rat or smaller.
The discovery wasn’t too surprising given that there are an estimated 2 to 5 million insects and spiders still to be discovered, but it’s a bit odd that it hadn’t been identified before. The abandoned mine that was found was not always abandoned, meaning it is very likely that miners once lived close to these giants.
Are there other mining spiders?
When it comes to spiders that like to live in long, winding caves and mines, it should come as no surprise that the cave orb weavers (meta menardi) are big fans. From the family Araneidae they choose Lord of the Rings Shelob’s approach to hunting by using silk to capture prey.
However, it is not always sticky, as in the case of meta menardi which uses its webs more as a trip wire to warn them of passing millipedes, snails and flies. According to the British Arachnological Society, it is a common resident of the entrance zones of caves and mines in the UK. They are far from the beastly size of C.cacachilsensisbut still very efficient fighters.
Other spiders have taken life in dark and remote places to such an extreme that they have evolved from using certain light-sensitive organs. Earlier this year, seven new troglobitic spider species entered the genus Counteraria were discovered in the caves of Israel. Of the seven new species found, five had reduced eyes, while the other two species were completely blind. Something to keep in mind if you’re on a casual cave walk: you’ve just adopted the dark, these arachnids were born into it.
If the prospect of mining spiders tickles you a bit, the simple solution of leaving these habitats alone should be enough to keep a comfortable distance. God knows New Zealand’s largest spider wishes people to stay out of the Crazy Paving Cave so they can hang their baby balls in peace.