The common name “Daddy Long Legs” is confusing because this single nickname is used to describe three completely distinct types of arthropods across different regions of the world. This confusion has led to persistent myths about a creature that is supposedly the world’s most venomous, yet harmless. The true answer involves a non-venomous arachnid, a mildly venomous spider, and a harmless flying insect, none of which pose any medical danger to humans.
Clarifying the Name: Three Different Creatures
The term “Daddy Long Legs” generally refers to the Harvestman, the Cellar Spider, or the Crane Fly. The first two are arachnids, while the third is an insect, placing them in entirely separate classes of the animal kingdom. Harvestmen, belonging to the order Opiliones, have a fused, oval body that appears to be a single segment, unlike true spiders. They possess eight legs and typically only two eyes, which are often located on a small turret on the top of their body.
Cellar Spiders, from the family Pholcidae, are true spiders (order Araneae) with eight legs, but their body is clearly divided into two distinct segments: the cephalothorax and the abdomen. Crane Flies, which belong to the insect order Diptera, are easily identified by their six legs and a single pair of wings, making them a type of fly.
Harvestmen (Opiliones): The Non-Venomous Arachnid
In many parts of the world, especially North America, the Harvestman is the creature most often identified as a “Daddy Long Legs.” Despite being an arachnid with eight legs, Harvestmen are not spiders and belong to the separate order Opiliones. This distinction is significant because Harvestmen completely lack the biological machinery required to produce venom, possessing neither venom glands nor true fangs.
Instead of fangs, they have chelicerae, which are modified mouthparts used for grasping and tearing food into small pieces. Their diet consists largely of decaying plant and animal matter, as well as small, soft-bodied insects, which they simply chew and consume. To defend themselves from predators, these arachnids rely on a chemical deterrent rather than venom. When disturbed, Harvestmen can release a peculiar-smelling fluid from a pair of prosomatic scent glands that contains noxious compounds, such as quinones, which discourage a potential attacker.
Cellar Spiders (Pholcidae) and the Venom Myth
The famous urban legend claims that the “Daddy Long Legs” is the most venomous spider in the world, but its fangs are too short to bite a human. This myth is most often associated with the Cellar Spider, a true spider that is also commonly called a “Daddy Long Legs Spider.” Cellar Spiders, like nearly all spiders, do possess venom glands and fangs. However, the idea that their venom is potent is not supported by scientific research; while the venom is effective enough to immobilize their typical prey, it is not considered medically significant to humans.
The claim about the fangs being too short is a half-truth that has fueled the myth for generations. Cellar Spiders do have fangs that are greatly reduced in size, measuring around 0.25 millimeters in length. While human skin thickness varies, the fangs are physically capable of penetrating the thin outer layer of skin if the spider were provoked. In a documented test, a bite from a Cellar Spider produced only a mild, brief burning sensation with no lasting effect. The myth persists because Cellar Spiders successfully prey on medically significant spiders, leading people to incorrectly assume they must possess a powerful venom. In reality, Cellar Spiders defeat their prey by aggressively casting thick silk to quickly ensnare and immobilize them from a distance, rather than relying solely on venom potency.
Crane Flies: The Harmless Insect Imposter
The third creature sometimes called a “Daddy Long Legs,” particularly in the United Kingdom, is the Crane Fly. Crane Flies are entirely different from the other two, as they are insects belonging to the family Tipulidae. They are often mistaken for giant mosquitoes due to their long, slender legs and delicate, winged appearance. These insects are completely non-venomous and are incapable of biting or stinging humans. The adult Crane Fly’s mouthparts are either non-functional or designed only for sipping nectar. Their inclusion in the “Daddy Long Legs” confusion is purely based on their long, fragile legs.