A common perception of “granddaddy long legs” involves a widespread myth about their danger. Many believe these creatures possess potent venom but are harmless because their fangs are too small to penetrate human skin. This notion has circulated for generations, leading to unnecessary fear. Examining scientific facts reveals a different reality, debunking the myth that they are deadly but unable to bite.
Identifying Granddaddy Long Legs
The term “granddaddy long legs” causes confusion as it refers to two distinct arthropods: harvestmen and cellar spiders. Harvestmen (order Opiliones) are arachnids, but not true spiders. They have a single, oval body segment where the cephalothorax and abdomen are broadly joined. Most harvestmen have two eyes, located on a raised mound in the middle of their carapace.
In contrast, cellar spiders (family Pholcidae) are true spiders. They possess two distinct body segments: a cephalothorax and an abdomen, connected by a narrow waist. Most cellar spiders have eight eyes, though some species may have six. Unlike harvestmen, cellar spiders produce silk and build messy, irregular webs, often found in basements and cellars.
Understanding Their Venom and Bite
Harvestmen are not venomous and do not have fangs. Their mouthparts are small, pincer-like chelicerae, designed for grasping and tearing food, not injecting venom. These mouthparts are too small and weak to break human skin. Harvestmen primarily feed on small invertebrates, dead insects, and decaying organic matter, functioning as scavengers.
Cellar spiders, being true spiders, do possess venom and fangs. However, their venom is considered mild and poses no medical threat to humans. Studies have shown cellar spider venom to be less potent than that of more dangerous spiders, such as the brown recluse. While their fangs can be up to 0.25 mm long, a bite, if it occurs, would cause only a mild, short-lived sensation, similar to a mosquito bite.
Why the Myth Endures
The persistent myth that “granddaddy long legs” are highly venomous but cannot bite humans stems from several factors. General fear of spiders and their intimidating appearance contribute to exaggerations about their danger. Confusion between harvestmen and cellar spiders also fuels the myth, as both are colloquially called “daddy long legs.”
Cellar spiders are known to prey on other spiders, including more venomous ones like black widows. This might lead people to assume their venom is potent, but cellar spiders often use silk to immobilize larger prey, rather than relying solely on their venom.
Living Peacefully with Granddaddy Long Legs
Both harvestmen and cellar spiders are largely harmless to humans and pets. Harvestmen play a beneficial ecological role as scavengers, consuming decaying organic matter and small invertebrates, contributing to nutrient cycling. They do not build webs and are often found in damp, sheltered areas.
Cellar spiders can also be beneficial inhabitants of homes, preying on various insects and other spiders, including common household pests like mosquitoes and flies. If encountered indoors, there is no need for alarm; they can simply be left alone or gently relocated. These creatures are a natural part of the ecosystem and pose no threat to human well-being.