Are daddy longlegs really the most venomous spiders in the world? - Livescience.com

You've probably heard this playground legend: Daddy longlegs are the most venomous spiders in the world, but their fangs are too short to bite you.

"First, what are you calling a daddy longlegs?" said Rick Vetter, a retired research associate of entomology at the University of California, Riverside.

The problem is that the term "daddy longlegs" is used colloquially to refer to at least three different animals, only one of which is a true spider. .

Like other spiders, it has two body segments, eight eyes and fangs, complete with venom ducts and venom glands. .

Unlike spiders, these animals have a single body segment and only two eyes, and they don't have fangs or venom glands.

"Harvestmen have little grabby mouthparts," Vetter told Live Science.

Clearly, daddy longlegs aren't just one thing.

Harvestmen don't have venom either — they have poison.

That leaves us with cellar spiders, the only true spiders of the bunch?

Their fangs are similar to those of the brown recluse (Loxosceles reclusa), Vetter said, which is notorious for its potentially fatal bite to humans.

"I'm not aware of any publication showing that pholcid spiders cause a toxic effect in humans," Vetter said.

On a 2004 "Mythbusters" episode that was later documented in a 2019 study, arachnologist Charles Kristensen reported injecting mice with venom of either cellar spiders or black widow spiders.

"That's a really good question, and I really don't have an answer for it," Vetter said.