FactSentinel

The claim combines two myths about the name "daddy longlegs," and neither holds up. The name is applied to three different animals: cellar spiders (family Pholcidae), harvestmen (order Opiliones), and crane flies. Harvestmen are not true spiders and have no venom glands at all. Crane flies are insects and are not venomous. Cellar spiders do produce venom, but there is no scientific evidence that it is especially potent, and they are nowhere near the most venomous spiders in the world. That title is usually associated with species such as the Brazilian wandering spider and the Sydney funnel-web spider, whose venom poses real medical risks to humans.

The idea that daddy longlegs have deadly venom but fangs too short to bite people is also unsupported. Cellar spiders can bite, and their fangs can pierce human skin, though the fangs are small and the bites are typically harmless. In a well-known test, a researcher allowed a cellar spider to bite him and reported only a faint, short-lived burning sensation. Their venom is considered weak in relation to human physiology, and medical sources do not recognize cellar spiders as dangerous.

The myth persists because it sounds plausible and has circulated for decades as a playground rumor. It is a "too dangerous but harmless by accident" story that is difficult to verify without knowing which animal is meant. Because the name covers several unrelated creatures, the myth is hard to pin down, but the consensus among arachnologists is that none of these animals are medically significant to people.