The question of whether “granddaddy long legs” are poisonous is common, often leading to confusion. This widespread misunderstanding stems from misidentification and persistent urban legends. While the answer is generally reassuring, understanding the specifics of these arachnids helps clarify why they pose little to no threat to humans. Dispelling these myths involves distinguishing between different types of “granddaddy long legs” and understanding the true nature of their biology.
Understanding the Confusion
The confusion surrounding “granddaddy long legs” arises because this common name is applied to at least two distinct types of arachnids. These are the Harvestmen, belonging to the order Opiliones, and Cellar Spiders, which are true spiders in the family Pholcidae. The myth often incorrectly attributes the characteristics of one to the other, or exaggerates perceived dangers of both.
A key distinction in understanding this topic is the difference between “poisonous” and “venomous.” An organism is considered poisonous if it releases toxins when ingested or absorbed through contact. Conversely, an organism is venomous if it actively injects toxins into another creature, typically through a bite or sting. This difference is central to debunking common misconceptions.
The Truth About Harvestmen
The creatures most commonly referred to as “granddaddy long legs” in many regions are Harvestmen, members of the order Opiliones. These arachnids are not true spiders, despite their similar appearance. A distinguishing feature is their body structure, where the cephalothorax and abdomen are broadly joined, making them appear as a single, oval segment, unlike the distinct two-part body of a spider.
Harvestmen do not possess venom glands or fangs, which means they cannot inject venom. Instead, they have small, pincer-like mouthparts (chelicerae) used for tearing food. These arachnids are harmless to humans.
Their diet primarily consists of small insects, plant material, fungi, and decaying organic matter, making them beneficial scavengers. As a defense, Harvestmen can secrete a foul-smelling fluid when disturbed. They may also shed a leg to escape a predator, which can continue to twitch, providing a distraction.
Cellar Spiders and Their Venom
Another arachnid frequently called “granddaddy long legs” is the Cellar Spider, belonging to the family Pholcidae. Unlike Harvestmen, these are true spiders, possessing two distinct body segments, fangs, and venom glands. Despite having venom, the myth about their venom being highly potent but their fangs too short to bite humans is unsubstantiated.
Cellar spiders do have short fangs, but they are capable of penetrating human skin. However, their venom is very mild and poses no significant threat to humans. If a bite occurs, symptoms are typically minimal, often described as a mild tingling or no reaction.
These spiders are generally shy and bites are rare, as they prefer to retreat from perceived threats. They often immobilize their prey, which includes other spiders and insects, using their silk rather than relying solely on venom. Therefore, despite being true spiders with venom, cellar spiders are not considered dangerous to humans.