Cellar Spider, Daddy Long-Legs Spider, Skull Spider
Pholcus phalangioides
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 remarkably delicate body with long, spindly legs disproportionate to its tiny cephalothorax and elongated, cylindrical abdomen. The cephalothorax is pale or cream-colored, often featuring a dark grey or brownish marking that gives it a skull-like appearance.
Size Estimate
Body length typically ranges from 7 to 10 millimeters, with a leg span reaching up to 5 to 7 centimeters.
Coloration & Markings
Mostly pale grey, pale yellow, or light brown. The abdomen is often grayish and can show subtle darker spots or chevrons. The carapace features a distinct darker central marking resembling a skull.
Web Type
Irregular, loose, three-dimensional tangle webs constructed in dark corners, cellars, basements, and behind furniture. They do not use sticky silk; instead, their tangled threads trap prey mechanically.
Eye Arrangement
Eight eyes clustered together on an elevated hump on the carapace. There are two triads of darker lateral eyes and a smaller pair of median eyes.
Leg Characteristics
Extremely long, thin, and fragile legs lacking dense spination. They can readily autotomize (shed) a leg if grabbed by a predator, and the detached leg will continue to twitch.
Venom & Safety Information
Venom Information
Contains a mild neurotoxin that is highly effective against their insect prey but incapable of penetrating human skin or causing systemic effects in humans.
Medical Significance
No medical significance. They are entirely harmless to humans, unable to bite through human skin, and do not pose any threat.
Safety Recommendations
No safety measures are necessary as they are completely harmless. If unwanted, they can be gently relocated using a cup and a piece of paper.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution worldwide. Primarily found indoors in human habitations such as cellars, basements, crawlspaces, and dark corners of rooms, as well as sheltered outdoor overhangs and caves.
Behavior & Temperament
Docile and completely harmless to humans. When disturbed, they perform a rapid vibrating or bouncing motion in their web to blur their outline and confuse potential predators.
Diet & Prey
Insects and other spiders, famously including larger spiders such as household funnel-web spiders and even venomous widows, which they subdue by wrapping them rapidly with silk from a distance.
Seasonal Activity
Active year-round indoors where climate-controlled environments provide stable temperatures, though reproduction often peaks during warmer months.
Description
The cellar spider is a familiar and harmless indoor resident known for its incredibly long legs and fragile build. Often referred to as a daddy long-legs, it weaves messy tangles in dark corners where it patiently waits for unsuspecting crawling insects.
Key Features
Extremely long, thin legs, pale translucent body, skull-like marking on the cephalothorax, and the characteristic rapid vibrating defense behavior when disturbed.
Similar Species
Opiliones (harvestmen, which are true arachnids but not spiders) and Phalangium opilio; harvestmen lack a constricted waist between body segments and do not spin silk.
Life Cycle
Females carry their eggs in a loose silk cluster held in their jaws until they hatch. Spiderlings undergo several molts to reach adulthood, with a typical lifespan of up to two to three years.
Ecological Importance
Serves as an effective natural pest controller in homes and buildings, helping to reduce populations of flies, mosquitoes, and other household pests.
Conservation Status
Not evaluated by the IUCN, but populations are abundant, widespread, and thriving globally alongside human habitations.
Interesting Facts
Despite an old urban legend claiming they possess the most potent venom of any spider but lack fangs capable of piercing human skin, this is completely false; their venom is quite weak.
Photography Tips
Use macro lenses with adequate side lighting to highlight the delicate leg joints and the unique cephalothorax markings against a neutral background.
Identified: 2026-07-29T13:50:30.810521