New Species Of Venomous Spider Found Hiding In Abandoned Mexican Mine Shafts


Robin Andrews

Science & Policy Writer


Why, what big fangs you have! Jim Berrian/San Diego Natural History Museum

Whether or not you think spiders are glorious little go-getters or bonafide monsters, it’s difficult to argue that the Brazilian wandering spider isn’t a frightening furball. Not only does it have spindly legs up to 15 centimeters (5.9 inches) long, but if you’re bitten by one, it causes lasting nerve damage and potentially death – along with giving any unfortunate male targets a rather persistent erection.

As the name suggests, this particular genus of spider is normally only found in parts of South America, but as reported in the journal Zootaxa, a new variant of the aggressive beastie can also be found clinging to the damp walls of Mexico’s caves and abandoned mines. Abandon hope all ye who enter there.


Wandering spiders are known to be nocturnal, and the new species (and genus) Califorctenus cacachilensis, or the Sierra Cacachilas wandering spider, is no exception to this. This meant that the researchers had to hunt around for these scuttling cave dwellers at night, and hope that they didn’t get bitten in the process. Unfortunately, this plan didn’t quite work out.

“I got bit while handling a live specimen of Califorctenus cacachilensis and I’m still alive,” co-author Jim Berrian, field entomologist at the San Diego Natural History Museum (SDNHM), said in a statement. “We haven’t analyzed the toxicity of the venom, but most wandering spiders are not as dangerous as the Brazilian wandering spider.”

The new beastie. Jim Berrian/San Diego Natural History Museum

So although the idea of this spider falling from a cave’s ceiling down the back of your shirt is no doubt an extremely unpleasant thought, there is some “good news” here – no matter how many times your exposed ankle or neck gets nibbled by one of these exotic creatures, you’ll most likely be fine.


The spider was first hinted at back in 2013 when a discarded exoskeleton of one was found clinging to a rock overhang in the Baja peninsula. Soon afterward, living specimens were found, all around 10 centimeters (4 inches) in length, mostly consisting of its long, spindly legs of doom.

Creepily, these new spiders do not spin webs – they simply run after they prey in the dead of night and pounce on them. Their powerful venom, injected into their prey through their small red “fangs”, is more than enough to incapacitate anything rat-sized or smaller within mere moments.

The team from SDNHM, along with researchers from Mexico and Brazil, suggest that this new spider is by some margin the largest found in the region.

“In all my experience over the years collecting spiders on the peninsula, I had never seen a spider this large,” Dr. Maria Luisa Jimenez, an expert on arachnids from the Northwest Center for Biological Investigations, added.


So, dear readers, there’s your daily dose of nightmare fuel.


  • tag
  • new species,

  • venom,

  • discovery,

  • night,

  • Mexico,

  • caves,

  • wandering spider,

  • mine shafts