Cellar Spider, Daddy Long-Legs Spider, Skull Spider
Pholcus phalangioides
Family 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 small, oval-to-elongated abdomen and a comparatively small cephalothorax. Its most striking physical feature is its exceptionally long, thread-like legs that give it a skeletal appearance. The body texture is smooth with sparse hairs, and sexual dimorphism is minor, though males often have slightly longer legs and prominent palps.
Size Estimate
Body length is typically around 7 to 10 millimeters, with a massive leg span reaching up to 5 to 7 centimeters. This appears to be a typical adult specimen based on body proportions and leg length.
Coloration & Markings
Pale gray, light brown, or yellowish with translucent qualities. The cephalothorax often features a distinctive darker grayish or brownish marking, sometimes described as having a shape vaguely resembling a violin or a skull.
Web Type
Builds irregular, tangled, 3D cobwebs in dark, quiet corners, ceilings, basements, and cellars. The web is not sticky in the traditional sense, but uses a sticky, viscous silk structure that wraps around prey.
Eye Arrangement
Six eyes arranged in a distinctive triad pattern: two groups of three eyes on elevated bumps on either side of the head, with a smaller pair sometimes present in the middle depending on the specific genus structure, characteristic of Pholcidae.
Leg Characteristics
Extremely long, thin, and fragile legs with delicate joints. They lack heavy spination but possess tarsal claws adapted for moving easily across irregular webs. When disturbed, the spider engages in rapid vertical bouncing or whirling in its web to blur its image.
Venom & Safety Information
Venom Information
Neurotoxic venom tailored specifically for immobilizing small invertebrate prey. While a persistent urban legend claims they have the most potent venom but short fangs, this is false; their venom is extremely weak and virtually harmless to humans.
Medical Significance
Harmless to humans. They lack the jaw structure and fang length to easily pierce human skin, and even if they do, their venom causes no systemic medical issues beyond a minor, temporary localized pinch or redness.
Safety Recommendations
No safety measures are necessary as they are completely harmless. If unwanted in living spaces, they can be gently caught in a cup and relocated to a garage or shed.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution found worldwide in temperate and tropical regions. Prefers dark, humid human-made structures such as cellars, basements, crawlspaces, garages, caves, and corners of rooms.
Behavior & Temperament
Docile and entirely non-aggressive toward humans. When threatened, it vibrates its body so fast it becomes invisible to predators, or drops from its web to escape. It is a persistent web-hunter.
Diet & Prey
Feeds on a wide variety of insects, other spiders (including venomous species like widow spiders and hobo spiders), and occasional small arthropods. It uses its long legs to cast silk over dangerous prey before delivering a bite.
Seasonal Activity
Active year-round indoors where climate-controlled environments protect them from seasonal temperature drops, though mating activity peaks during warmer months.
Description
The cellar spider is a ubiquitous and harmless household resident known for its impossibly long legs and messy webs in room corners. Despite their delicate appearance, they are fierce predators in the micro-world, capable of subduing much larger spiders and insects.
Key Features
Extremely long, thin legs relative to a tiny body, pale brownish-gray coloration, irregular 3D cobweb in corners, and the signature defensive bouncing behavior when disturbed.
Similar Species
Harvestmen (Order Opiliones, also called daddy long-legs) which are not true spiders (they have a fused body and lack silk glands and venom), and Pholcus opilionoides which is smaller and similarly patterned.
Life Cycle
Females construct a loose silk sac containing around 20 to 60 eggs, which they carry in their chelicerae until hatching. Spiderlings undergo several molts before reaching maturity, and adults can live for several years.
Ecological Importance
Serves as a natural pest control agent inside homes and buildings, keeping populations of flies, mosquitoes, and other household pests in check without any human intervention.
Conservation Status
Not evaluated by the IUCN, but populations are extremely secure, widespread, and thriving globally alongside human habitations.
Interesting Facts
Cellar spiders are famous for actively hunting and consuming larger, more dangerous spiders like black widows. They also vibrate so rapidly when disturbed that they appear to disappear.
Photography Tips
Use macro lenses with good depth of field to capture the entire leg span, photograph against a contrasting background, and use diffused lighting to avoid harsh shadows on the translucent body.
Identified: 2026-10-02T14:01:38.258100