The spider that can bite through a fingernail.
The Sydney funnel-web spider is one of the most dangerous spiders in the world. Its fangs are 5 mm (0.2 in) long; they are hardened & downward-pointing & strong enough to penetrate our fingernails, skin & leather. Worse yet is the powerful venom it contains. If one should bite a child & they didn't receive prompt medical intervention with antivenom, the child would die within minutes. The antivenom is a lab-madeantibody treatment that binds to atracotoxins & neutralizes them. The venom contains atraxotoxins, a family of neurotoxic proteins that force nerve cells to fire uncontrollably, causing muscle spasms, breathing difficulty, sweating & drooling. The toxin can overload the heart & lungs, making it a struggle to breathe & leading to a dangerously fast heart rate, collapse & death. Males are more dangerous than females because their venom contains more potent atracotoxins. They wander more, increasing human encounters. Thankfully, modern medicine has eliminated fatalities since 1981.
But not so for the deadliest spider on Earth—the Brazilian wandering spider. It has multiple confirmed fatalities in South America, including Brazil, Colombia, Peru, Ecuador, & Venezuela, as well as parts of Central America. They hide in banana plants, forest floors, sheds & homes at night. It is highly aggressive, & its venom is a cocktail of neurotoxic peptides, toxins 1 through 6. Each number produces different symptoms & targets a specific part of the body; for example, Tx1 disrupts nerve firing & Tx2 causes pain, muscle dysfunction & priapism in males (a prolonged painful erection that lasts for 4 hours or more without sexual stimulation).
Interestingly, Casanova used Spanish Fly, which also causes priapism, & gave the substance to women he seduced without them knowing. The 3rd part of its toxin, Tx3, prevents nerves from releasing neurotransmitters, causing tremors, loss of muscle control, breathing difficulty & severe pain. Tx 5 breaks down tissue, making it easier for the venom to spread. Most bites cause extreme pain but not death, but severe cases involve children & the elderly. Those are the cases where the antivenom for the Brazilian wandering spider is reserved.














