Daddy longlegs is the general term given to several different arachnids with small bodies and long spindly legs. Depending on where one lives, this name may refer to cellar spiders, harvestmen, or other similar-looking arachnids. These harmless animals are common across the globe.
When people talk about daddy longlegs, they are usually referring to arachnids belonging to two separate orders. These animals resemble one another, but one is actually a spider and the other is not. The daddy longlegs of the order Opiliones are also commonly known as Hharvestmen, and although they are arachnids, they are not spiders. Daddy longlegs of the family Pholcidae are actually spiders and are commonly called "cellar spiders."
Daddy longlegs are distinguished from similar arachnids by their comparatively long legs and rather small bodies. Daddy longlegs belonging to the Opiliones order (harvestmen) can be further distinguished from those in the Pholicidae family (cellar spiders) by their body segments. Opiliones have one simple body segment, while Pholicidae show two distinctive body segments. Furthermore Opiliones have two eyes as compared to Pholicidae, which have eight.
Harvestmen generally eat vegetative matter and decomposing animal matter. They are scavengers and very opportunistic eaters. However Opiliones lack fangs, so their predation is rare. Harvestmen do not produce silk and cannot create webs to catch food. Pholicidae are true spiders, so their eating habits are quite different from those of harvestmen. These "cellar spiders" are hunting spiders, which use their fangs to subdue their insect prey.
Harvestmen can be found in moist habitats (although some reside in desert habitats as well) and prefer to spend their time under logs, rocks, and leaf litter. Cellar spiders on the other hand can be found in numerous habitats. These spiders thrive in desert habitats and along the Pacific coast, although they will live in homes throughout the United States and Europe. They are especially numerous in cellars and basements, giving them their common name.
A popular myth states that daddy longlegs are the most venomous creatures on earth, but that their mouths are too small to bite a human. This is absolutely false. It is not known how this myth originated; according to the scientists at the University of California, Riverside there is no evidence at all to suggest that the bite of a daddy longlegs is harmful to humans.