Cellar Spider, Daddy Long-Legs Spider, Skull Spider
Pholcus phalangioides
Pholcidae (Cellar Spiders), Order Araneae
Physical Description
Delicate, fragile body with a small, rounded or oval abdomen and long, slender legs. The cephalothorax is typically wider than it is long and often features a dark marking that resembles a skull shape in some species.
Size Estimate
Body length typically ranges from 7 to 10 millimeters, with a much larger leg span reaching up to 5 to 7 centimeters.
Coloration & Markings
Pale, translucent tan, gray, or yellowish coloration with faint darker markings or spots on the abdomen and cephalothorax.
Web Type
Irregular, messy tangle webs (cobwebs) constructed in corners, basements, and high-moisture areas like bathrooms.
Eye Arrangement
Eight eyes arranged in two lateral triads and a pair of smaller median eyes situated on an elevated mound.
Leg Characteristics
Exceptionally long and thin legs with high flexibility, lacking heavy spination, often held flat or used to bounce the spider when disturbed.
Venom & Safety Information
Venom Information
Mild neurotoxic venom designed specifically for small invertebrate prey; extremely weak effect on humans and unable to easily puncture human skin.
Medical Significance
Harmless to humans. Despite urban legends regarding extreme toxicity, they pose zero medical risk and are considered beneficial household guests.
Safety Recommendations
No safety measures needed as they are completely harmless. If relocation is desired, gently guide them into a cup using a piece of paper.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution worldwide; commonly found indoors in dark, humid environments such as cellars, basements, bathrooms, and garages.
Behavior & Temperament
Docile and non-aggressive; employs a unique defensive behavior of vibrating or bouncing rapidly in its web to become a blur to predators.
Diet & Prey
Insects and other spiders, famously including venomous species like redbacks and hobo spiders, which they subdue by throwing silk using their long legs.
Seasonal Activity
Active year-round indoors, though mating and increased movement are often observed during warmer spring and summer months.
Description
The cellar spider is a familiar and harmless presence in homes around the world. Easily recognized by its incredibly long legs and fragile body, it prefers the quiet corners of bathrooms and basements. Rather than fleeing, disturbed individuals perform a rapid vibrating dance to confuse predators. Far from being a pest, this proficient hunter helps keep homes free of more troublesome insects and even other spiders.
Key Features
Extrordinarily long, thread-like legs, delicate translucent body, messy corner cobweb, and the characteristic bouncing defense mechanism.
Similar Species
Harvestmen (Opiliones), which are not true spiders and lack a segmented waist, and cellar-dwelling spitting spiders (Scytodidae).
Life Cycle
Females carry eggs in a loose silk cluster held in their jaws. Spiderlings hatch as miniature adults and undergo several molts before reaching maturity.
Ecological Importance
Acts as an effective natural pest controller in indoor environments, helping to regulate populations of flies, mosquitoes, and other household insects.
Conservation Status
Not evaluated by the IUCN, but highly abundant, secure, and thriving globally alongside human habitations.
Interesting Facts
Cellar spiders are famous for hunting and defeating much larger, potentially dangerous spiders like black widows by wrapping them in silk from a safe distance using their long legs.
Photography Tips
Use macro lenses with good side lighting to highlight the delicate translucent anatomy and distinct eye arrangement against a clean background.
User Notes
On the bathroom wall
Identified: 2026-08-18T19:05:35.848677