Are daddy longlegs the most venomous animals?

No. The claim that daddy longlegs carry deadly venom but can't bite people is an urban legend. Harvestmen have no venom at all, US cellar spiders' venom is harmless to people, and in the UK the name usually means the crane fly, a harmless insect.

What's actually true

Harvestmen ('daddy longlegs' in the US) are not secretly deadly. A popular legend says these long-legged creatures carry deadly venom but can't bite us. Spider experts at the Burke Museum call it baseless. Harvestmen have no venom at all. In the US the nickname also covers cellar spiders, whose venom is harmless to people. In the UK, 'daddy longlegs' usually means the crane fly, a harmless insect.

Takeaway: Whatever your local 'daddy longlegs' is, it isn't dangerous to you.

Why people believe it

The legend combines two things that sound plausible: these creatures look fragile yet are everywhere, and their thin bodies seem too small to bite through skin. 'The most venomous but harmless' makes a great paradox to pass on. The name adds confusion, because 'daddy longlegs' refers to different animals in different countries, so any fact about one gets attached to the others, and nobody can easily check which creature the story was about.

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