The common name “Daddy Long Legs” causes confusion because it refers to multiple creatures. A persistent urban legend claims this animal possesses the world’s most potent venom but lacks the ability to pierce human skin. To understand the true risk, it is necessary to identify which of the three distinct, long-legged arthropods is being discussed. Two are harmless to humans, while the third, a true spider, has medically insignificant venom.
Understanding the “Daddy Long Legs” Identity Crisis
The term “Daddy Long Legs” refers to three distinct creatures: the Harvestman (Order Opiliones), the Cellar Spider (Family Pholcidae), and the Crane Fly (Family Tipulidae). The Harvestman is an arachnid but not a true spider, the Cellar Spider is a true spider, and the Crane Fly is an insect with wings.
These organisms have distinct physical differences. Harvestmen have a single, fused body segment, two eyes, and cannot spin silk. Cellar Spiders, like all true spiders, have two distinct body segments (cephalothorax and abdomen) and typically possess eight eyes. Crane Flies are distinguished from arachnids by their six legs and two delicate, membranous wings.
Harvestmen and Crane Flies: No Threat to Humans
Two of the creatures commonly called “Daddy Long Legs” pose no threat to people. The Harvestman, an arachnid, is completely non-venomous because it lacks the venom glands present in true spiders. This makes the myth of it having potent venom untrue.
Harvestmen use small, pincer-like mouthparts (chelicerae) for grasping and tearing food, not for injecting venom. They are scavengers and opportunistic predators, consuming small insects, decaying plant matter, and fungi. Their mouthparts are not strong enough to break human skin, rendering them harmless.
The Crane Fly, an insect, is also incapable of biting humans. Belonging to the Order Diptera (true flies), adult Crane Flies have delicate, elongated mouthparts adapted for sipping water or nectar, or they may not feed at all. They lack the necessary anatomy for biting, stinging, or sucking blood.
Cellar Spiders: The Truth About Biting and Venom
The Cellar Spider (Family Pholcidae) is the only true spider of the three, possessing both fangs and venom. However, the myth that this spider is among the most venomous in the world is incorrect. While its venom is effective against small invertebrate prey, it is considered medically insignificant to humans.
Cellar spiders have the anatomical ability to bite, but their fangs are small, and they are extremely reluctant to do so. A bite is rare and typically requires significant provocation, such as pressing the spider against the skin. When a bite occurs, symptoms usually amount to a minor, short-lived burning sensation or a slight itch that quickly subsides.
The persistent myth that the Cellar Spider is dangerously venomous but cannot pierce human skin has been definitively debunked. Although their fangs are small, they are structurally capable of penetrating the skin. However, the venom injected is too weak to cause any detrimental reaction in people. This true spider is ultimately a harmless resident, often found hanging upside down in its messy, irregular webs.