Cellar Spider, Daddy Long-Legs Spider, Skull Spider
Pholcus phalangioides
Family Pholcidae (Cellar Spiders), Order Araneae. Key family characteristics include exceptionally long, fragile-looking legs and a fused or closely associated group of six to eight eyes.
Physical Description
The spider has a small, oval to pear-shaped abdomen and a relatively compact cephalothorax. Its most striking physical feature is its extremely long, thread-like legs. The body texture is smooth with sparse hairs. Sexual dimorphism is minimal, though females often have slightly larger abdomens.
Size Estimate
Body length is typically 7-10 mm, but with the exceptionally long legs, the total leg span can reach 50-70 mm (2-3 inches). This appears to be an adult specimen.
Coloration & Markings
Pale gray, yellowish, or translucent white base coloration. The cephalothorax often features a dark, distinctive marking that can resemble a faint violin shape or skull pattern, and the abdomen may display pale greyish markings.
Web Type
Constructs an irregular, messy, three-dimensional tangle web (cobweb) in dark, damp corners, cellars, basements, and upper room angles.
Eye Arrangement
Consists of eight eyes clustered closely together on an elevated portion of the cephalothorax, typical of the Pholcidae family, featuring a triad on each side and two smaller median eyes.
Leg Characteristics
Extremely long, thin, and fragile legs with very fine spination. When disturbed, the spider characteristically vibrates its web rapidly in a blur to evade predators.
Venom & Safety Information
Venom Information
Contains a mild neurotoxin primarily adapted for subduing small insect prey. Despite the urban legend, their venom is not dangerous to humans.
Medical Significance
Harmless to humans. Their fangs are generally too short or weak to pierce human skin, and envenomation is exceedingly rare and medically insignificant.
Safety Recommendations
No special safety precautions are necessary. If unwanted indoors, they can easily be caught in a cup and relocated outside unharmed.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution worldwide, thriving indoors in human habitations such as basements, crawlspaces, garages, and dark corners of rooms. Outdoors, they inhabit caves, rock crevices, and beneath loose bark.
Behavior & Temperament
Docile and non-aggressive. They spend most of their time hanging upside down in their webs. When threatened, they engage in a frantic vibrating motion (gyrating) to confuse predators.
Diet & Prey
Generalist predators feeding on insects and other spiders. Notably, they are famous for preying on other, potentially more dangerous spiders like black widows or hobo spiders, using silk wraps deployed from a distance.
Seasonal Activity
Active year-round indoors where temperature-controlled environments maintain constant activity, though mating and reproduction often peak during warmer spring and summer months.
Description
The cellar spider is a familiar and harmless indoor roommate characterized by its incredibly long legs and delicate body. Often found hanging motionless in the dark corners of rooms or basements, it plays an effective role in natural pest control inside homes.
Key Features
Extremely long, spindly legs; pale, translucent body; irregular cobweb construction; and the characteristic frantic vibrating defense mechanism when disturbed.
Similar Species
Often confused with harvestmen (Opiliones, also called daddy long-legs) and crane flies (Tipulidae), neither of which are spiders. True cellar spiders can be distinguished by their segmented two-part body and silk-producing abilities.
Life Cycle
Females carry their pale, loose egg sacs wrapped in a thin web layer in their mouthparts until hatching. Spiderlings undergo multiple molts to reach maturity, with a lifespan that can span several years.
Ecological Importance
Serves as a beneficial household and natural predator, helping to regulate populations of flies, mosquitoes, and other nuisance insects or medically significant spiders.
Conservation Status
Not evaluated by the IUCN, but populations are abundant, stable, and thriving globally alongside human dwellings.
Interesting Facts
Cellar spiders are famous for an urban legend claiming they are the most venomous spiders in the world but have fangs too short to bite humans—a claim that is entirely false. They are also known to actively invade the webs of other spiders to consume the resident.
Photography Tips
Use macro lenses with a high depth of field to capture both the tiny cephalothorax markings and the extremely long legs. A neutral background helps isolate the translucent body.
Identified: 2026-07-29T02:39:35.538798