Why are these spiders so deadly to humans?

Spider by JoAnna Wendel Updated: Feb. 20, 2024 Originally Published: Sep. 23, 2020 Shutterstock

Shutterstock The Sydney Funnel Web spider is one of the world’s most venomous spiders.

Shutterstock Its venom wreaks havoc on our nerves, making them turn on and fire uncontrollably.

Shutterstock This reaction can cause muscle spasms, excessive sweating, vomiting, and even death — all within 15 minutes of being bitten.

Shutterstock Males, in particular, have much more potent venom. Most human deaths caused by Sydney Funnel Web spiders have been attributed to the males.

Why would this spider’s venom be so toxic to humans — and our primate cousins — when we didn’t evolve as its natural predator or prey? And why is the male’s venom so much more potent?

A team of scientists recently set out to solve this mystery, and it turns out... pure evolutionary coincidence can explain this deadly match-up.

Shutterstock When male spiders reach sexual maturity, they leave their burrows in search of a mate.

Shutterstock Venturing out into the world can be dangerous, so male Sydney Funnel Web spiders had to evolve a self-defense mechanism.

The toxin in the Sydney Funnel Web spider’s venom, called Delta-hexatoxins, causes pain in other animals like mice, the scientists found. David Wilson

The venom most likely evolved to fight off predators like birds, lizards, and bandicoots, on the male’s search to find a mate.

Shutterstock It's just an unfortunate coincidence that the venom can kill humans, too.

Shutterstock The new findings could help scientists develop treatments for the nasty bites.

Why are these spiders so deadly to humans?

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