“Daddy longlegs are the most venomous spiders but their fangs are too small to bite humans”

The common misconception that "daddy longlegs" are incredibly venomous but harmless due to small fangs stems from a significant case of mistaken identity and exaggerated folklore. The term "daddy longlegs" is colloquially applied to at least two, and sometimes three, distinct creatures: harvestmen (order Opiliones), cellar spiders (family Pholcidae), and occasionally crane flies (order Diptera). The myth itself likely originated from observations, particularly in places like Australia, where cellar spiders have been seen preying on highly venomous spiders like redback spiders, leading to the incorrect assumption that the cellar spider's venom must be even more potent.

Scientifically, harvestmen are not spiders at all, though they are arachnids. A key distinguishing feature is their single, fused body segment, unlike true spiders which have two distinct body segments. Crucially, harvestmen possess no venom glands or fangs whatsoever, rendering them completely harmless to humans. Instead of venom, when disturbed, they may emit a foul-smelling fluid as a defense mechanism. Their mouthparts are small, grasping claws, not hollow fangs for injecting venom.

On the other hand, cellar spiders, which are also often called "daddy longlegs" due to their long, thin legs, *are* true spiders. Like most spiders, they do produce venom and have fangs. However, their venom is mild and primarily effective against the small insects they prey upon. While their fangs are indeed short, they are capable of piercing human skin, though bites are rare and typically result in only a mild, localized stinging sensation, far less severe than a bee sting.

The persistence of this myth can be attributed to the confusing common name shared by different species, their similar long-legged appearance, and perhaps a general human tendency to sensationalize perceived dangers in the natural world. Despite the widespread belief, neither harvestmen nor cellar spiders pose a significant threat to humans. Harvestmen are entirely non-venomous, and while cellar spiders have venom, it is weak and their bites are uncommon and harmless to people.