Long-bodied Cellar Spider, Daddy Long-legs Spider, Skull Spider
Pholcus phalangioides
Pholcidae (Cellar Spiders), Order Araneae
Physical Description
Characterized by an extremely thin, elongated, cylindrical abdomen and a small, somewhat flattened cephalothorax. The body has a delicate, almost translucent appearance with very fine hairs visible only under magnification.
Size Estimate
Body length: 7-9 mm for females, slightly smaller for males. Leg span: can reach up to 50-70 mm (approximately 2-3 inches).
Coloration & Markings
Pale tan, grayish, or light brown overall. The cephalothorax often features a dark, blurry mark resembling a skull or a 'blob' in the center. The abdomen is typically monochromatic but may have faint, darkish spots or striations.
Web Type
Builds messy, irregular, three-dimensional tangle webs (cobwebs). The web is not sticky; instead, it relies on its chaotic structure to entangle prey. Placement is typically in dark, quiet corners of buildings.
Eye Arrangement
Eight eyes arranged in three groups: two lateral groups of three eyes each and one pair of small anterior median eyes in the center. This 'triad' arrangement is a hallmark of the family Pholcidae.
Leg Characteristics
Extremely long, spindly, and fragile-looking legs. The legs are roughly 5 to 6 times the length of the body. They lack heavy spines or distinct banding, often appearing nearly transparent or straw-colored.
Venom & Safety Information
Venom Information
Contains venom effective against small arthropods but it is not known to be toxic to humans. Contrary to urban legends, they are not the 'most venomous spiders in the world'; their venom is quite weak by human standards.
Medical Significance
Harmless to humans. Their fangs are very short (approx. 0.25mm), and while they can theoretically pierce human skin, bites are extremely rare and result in nothing more than a mild, short-lived stinging sensation, if anything at all.
Safety Recommendations
No special safety measures required. If they are unwanted, they can be easily moved outside using a broom or a jar. They are beneficial houseguests and generally best left alone to provide natural pest control.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution worldwide due to human transport. Found primarily in synanthropic habitats like basements, garages, attics, and dark corners of houses. In warmer climates, it may live under rock overhangs or in caves.
Behavior & Temperament
Passive and reclusive. When threatened or disturbed in its web, it exhibits a unique 'whirling' or vibrating behavior, spinning its body rapidly to become a blur to predators. It is not aggressive toward humans.
Diet & Prey
Insects, woodlice, and frequently other spiders. They are formidable predators of larger spiders, including house spiders and even medically significant species like Black Widows, which they overcome using their long legs to wrap silk from a distance.
Seasonal Activity
Active year-round in temperature-controlled indoor environments. In unheated areas, they may be less active during winter but do not typically hibernate.
Description
A ubiquitous and misunderstood inhabitant of homes worldwide, the Cellar Spider is a master of corners. Its skeletal frame and slow, deliberate movements mask a highly effective predator that provides free pest control for homeowners. It is easily identified by its extremely long legs and habit of hanging upside down in messy webs.
Key Features
Cylindrical greyish body, extremely long spindly legs, 3-group eye arrangement, and the habit of vibrating or whirling when disturbed.
Similar Species
May be confused with Harvestmen (Opiliones), which have a single body segment and no silk, or other Pholcids like Psilochorus species which have more globular, rounded abdomens.
Life Cycle
Females carry their egg sacs (containing 20-50 eggs) in their chelicerae (jaws) rather than attaching them to the web. Spiderlings are translucent. Adults can live for up to 3 years in protected indoor environments.
Ecological Importance
High value for indoor pest control. They actively hunt and kill mosquitoes, flies, moths, and other spiders, keeping household insect populations in check without the need for chemicals.
Conservation Status
Not evaluated (NE). They are extremely common and widespread, thriving in man-made structures.
Interesting Facts
The myth that they are the most venomous spiders but have fangs too short to bite humans is false; they are neither highly venomous nor incapable of biting, they just rarely choose to do so and have very weak venom.
Photography Tips
Use a macro lens if possible. Focus on the cephalothorax to capture the eye arrangement. Because they are often in dark corners, a diffused flash is necessary to prevent harsh shadows on the nearby walls.
Identified: 2026-06-11T18:46:25.878391