Cellar Spider, Daddy Long-Legs Spider, Skull Spider
Pholcus phalangioides
Pholcidae (Cellar Spiders), Order Araneae. Key family characteristics include long, delicate legs, a small fused cephalothorax, and the habit of vibrating rapidly when disturbed.
Physical Description
The spider has a distinctively small, oval cephalothorax and a larger, elongated to rounded abdomen. The body appears somewhat fragile and translucent, with pale coloration. The texture is smooth, and sexual dimorphism is generally minimal.
Size Estimate
Body length typically ranges from 7 to 10 millimeters, with an extended leg span reaching up to 5 to 7 centimeters.
Coloration & Markings
Pale gray, tan, or light yellowish-brown base coloration. The cephalothorax often features a darker, distinct dark mark or pattern sometimes resembling a skull shape.
Web Type
Irregular, messy tangle webs (cobwebs) constructed in dark, damp corners, cellars, basements, and ceilings. They do not use sticky silk, instead relying on the chaotic web structure to trap prey.
Eye Arrangement
Eight eyes arranged in three groups: a triad on each side and a tight cluster of two (median eyes) in the center front, elevated on a small bump.
Leg Characteristics
Extremely long, thin, and delicate legs with faint darker banding. When disturbed, the spider executes rapid vibrating or oscillating movements to blur its outline.
Venom & Safety Information
Venom Information
Neurotoxic venom tailored specifically for arthropod prey. It is extremely weak against humans and generally cannot penetrate human skin effectively.
Medical Significance
Harmless to humans. Despite urban legends claiming they are deadly with short fangs, they pose zero medical threat and their bites rarely cause any noticeable symptoms.
Safety Recommendations
No safety measures needed as they are completely harmless. If desired, they can be gently relocated using a cup and a piece of paper.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution worldwide, predominantly found indoors in human dwellings, cellars, garages, and damp sheds, as well as caves and under rock ledges outdoors.
Behavior & Temperament
Docile, timid, and non-aggressive toward humans. They are sit-and-wait predators that stay motionless in their webs until prey triggers the silk.
Diet & Prey
Insects and other spiders, famously including larger spiders like venomous widows and funnel-web spiders, which they successfully subdue by wrapping them in silk from a distance.
Seasonal Activity
Active year-round indoors due to climate-controlled environments, with increased mating activity during warmer months.
Description
The cellar spider is a familiar household guest known for its impossibly long legs and preference for out-of-reach corners. Though delicate in appearance, it is a surprisingly fierce predator capable of subduing much larger spiders.
Key Features
Extremely long thin legs, pale translucent body, darker marking on the cephalothorax, and the signature rapid-vibration defense mechanism.
Similar Species
Harvestmen (Opiliones, which are not true spiders and lack silk glands) and Phalangium opilio; cellar spiders are distinguished by having two distinct body segments.
Life Cycle
Females carry eggs in a loose silk sac held in their jaws. Spiderlings hatch as miniature adults, undergoing multiple molts over a lifespan that can exceed two years.
Ecological Importance
Act as natural pest controllers inside homes by keeping populations of flies, mosquitoes, and other household arthropods in check.
Conservation Status
Not evaluated by the IUCN; abundant, widespread, and thriving globally alongside human habitations.
Interesting Facts
Cellar spiders are known for 'spider-to-spider' combat where they invade other spiders' webs and mimic prey vibrations to lure the resident out.
Photography Tips
Use macro lenses with good side-lighting to capture the translucent body and eye arrangement. Shoot against a contrasting background from a safe, steady distance.
Identified: 2026-09-06T04:25:19.871752