Cellar spider, Daddy long-legs spider, Vibrating spider
Pholcus phalangioides
Family Pholcidae (Cellar Spiders), Order Araneae. Key family characteristics include extremely long, delicate legs and an oval or elongated abdomen.
Physical Description
The spider has a small, globular abdomen and a distinctly fused cephalothorax. It features exceptionally long, thin legs relative to its body size, giving it a frail, spindly appearance.
Size Estimate
Body length is approximately 7 to 10 millimeters, with a total leg span reaching up to 50 millimeters (5 cm).
Coloration & Markings
Pale brown, grayish, or translucent coloration with darker markings on the cephalothorax and sometimes subtle chevron patterns on the abdomen.
Web Type
Irregular, tangled three-dimensional cobweb constructed in dark, damp corners, cellars, basements, and behind furniture.
Eye Arrangement
Eight eyes arranged in a triad on each side with a pair of smaller eyes in the center, typical of the Pholcidae family.
Leg Characteristics
Extremely long, thin, and fragile legs lacking strong spines, equipped with flexible tarsi that allow them to vibrate rapidly when disturbed.
Venom & Safety Information
Venom Information
Neurotoxic venom tailored for small arthropods. Completely harmless to humans as their fangs are too small to pierce human skin effectively.
Medical Significance
Not medically significant. Completely harmless to humans despite urban legends regarding venom toxicity.
Safety Recommendations
No safety measures needed as they are completely harmless. Can be gently relocated using a cup and paper if unwanted indoors.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution worldwide, predominantly found indoors in human habitations, dark corners, cellars, garages, and damp outbuildings.
Behavior & Temperament
Docile and non-aggressive. When disturbed, it rapidly oscillates or vibrates its body within the web to blur its outline and confuse predators.
Diet & Prey
Insects and other spiders, including medically significant species like the redback or hobo spider, which it wraps in silk and subdues efficiently.
Seasonal Activity
Active year-round indoors due to climate-controlled environments, with mating occurring primarily during warmer months.
Description
The cellar spider is a familiar household guest, easily recognized by its tiny body and ridiculously long legs. Often referred to as daddy long-legs, it harmlessly occupies dark corners of basements and ceilings, acting as an effective natural pest controller.
Key Features
Extremely long, thread-like legs, small oval body, pale translucent coloration, and the characteristic rapid vibrating defense behavior when touched.
Similar Species
Harvestmen (Opiliones, also called daddy long-legs) which are not true spiders; Pholcus species can be distinguished from harvestmen by their segmented body parts and silk-spinning ability.
Life Cycle
Females carry eggs in a loose silk cluster held in their jaws until hatching. Spiderlings undergo several molts, and adults can live for several years.
Ecological Importance
Serves as an important domestic predator that helps control household pest populations, including flies, mosquitoes, and other spiders.
Conservation Status
Not evaluated by the IUCN, highly secure and abundant globally alongside human habitations.
Interesting Facts
Despite an urban legend claiming they are the most venomous spiders with mouths too small to bite humans, this is entirely false; their venom is weak to vertebrates and they can occasionally bite humans, causing only mild local irritation.
Photography Tips
Use macro lenses with good side lighting to highlight leg joints and eye arrangements. Keep a steady hand or use a tripod as these spiders inhabit dim areas requiring lower shutter speeds.
Identified: 2026-08-14T22:40:45.474436