The common term “daddy long legs” frequently causes confusion, as it refers to different creatures across various regions. This widespread colloquialism often leads to questions about the identity of these long-legged arthropods, especially whether cellar spiders are included among them. Understanding the distinct biological features of these animals is important to clarify this popular misconception.
Cellar Spiders Unveiled
Cellar spiders, belonging to the scientific family Pholcidae, are true spiders characterized by their extremely long, thin legs and small, often oval-shaped bodies. Their coloration typically ranges from pale yellowish to light brown or gray. These spiders are commonly found in dark, damp environments such as cellars, basements, and the corners of rooms, which gives them their common name.
They construct irregular, messy webs in undisturbed areas, often hanging upside down within them. These webs are not sticky, but rather a complex matrix designed to entangle prey. Cellar spiders primarily feed on insects like mosquitoes, gnats, and flies, and also prey on other spiders, including larger species. When disturbed, some species exhibit a rapid, gyrating motion in their webs, leading to their alternative name “vibrating spiders.”
The True Harvestmen
Harvestmen (Opiliones) are arachnids, but not spiders. A key distinguishing feature is their body structure, where the cephalothorax and abdomen are broadly joined, making their body appear as a single, oval segment. Most harvestmen have only two eyes, typically located on a raised mound on their carapace, unlike spiders which usually have six to eight eyes.
Unlike spiders, harvestmen do not possess silk glands, meaning they cannot spin webs. They also lack venom glands and fangs, relying instead on chelicerae (mouthparts) to grasp and tear apart their food. Harvestmen are omnivores, feeding on small insects, fungi, plant material, and carrion, making their diet broader than most predatory arachnids. They are often nocturnal and use their second pair of legs as sensory organs to explore their environment, as their vision is generally poor.
Crane Flies and Other Long-Legged Insects
Crane flies (Tipulidae) are another group sometimes called “daddy long legs.” These are insects, not arachnids, and can be distinguished by their slender bodies, two wings, and extremely long, fragile legs. They often resemble oversized mosquitoes but are entirely harmless to humans.
Adult crane flies generally do not feed, with some species lacking functional mouthparts entirely, or only consuming nectar. Their primary purpose as adults is reproduction, and they typically have very short lifespans, often only a few days. Crane fly larvae, sometimes called “leatherjackets,” live in moist soil or aquatic environments and feed on decaying organic matter or plant roots.
Settling the Confusion and Dispelling Myths
The term “daddy long legs” is ambiguous, referring to cellar spiders, harvestmen, or crane flies depending on regional usage.
Distinguishing between these groups involves observing their body structure and other biological features. Cellar spiders are true spiders with two distinct body segments (cephalothorax and abdomen) and typically eight eyes, and they spin irregular webs. Harvestmen, conversely, have a single, fused body segment, generally two eyes, and do not produce silk or venom. Crane flies, being insects, possess six legs, wings, and segmented bodies, clearly differentiating them from arachnids.
A persistent myth suggests that “daddy long legs” possess the world’s most potent venom but cannot bite humans. This myth is largely associated with cellar spiders. While cellar spiders do have venom, it is not considered dangerous to humans and their fangs are very small, making bites rare and generally harmless. Harvestmen, on the other hand, lack venom glands entirely, posing no threat whatsoever.