Feather-legged Orb-weaver, Hackled Orb-weaver
Uloborus glomosus
Uloboridae (Hackled Orb-weaver Spiders), Order Araneae. This family is unique for lacking venom glands.
Physical Description
A small spider with a compact, humped cephalothorax and a high, rounded abdomen. The first pair of legs is notably longer and thicker than the others, often held straight forward. High degree of sexual dimorphism with females being significantly larger and more bulbous.
Size Estimate
3mm to 6mm body length. The specimen in the image is likely a juvenile or a male, appearing as a very small, slender dark speck against the fabric.
Coloration & Markings
Typically mottled grey, brown, or black to blend in with debris. They often feature white or dark bands on the legs and a series of dark tufts of hair on the first pair of legs (tibia).
Web Type
Horizontal or angled orb web made of non-sticky cribellate (fuzzy) silk. Often found in corners of buildings, under eaves, or in dense vegetation.
Eye Arrangement
8 eyes arranged in two rows; the posterior row is widely spaced, helping them detect movement from above.
Leg Characteristics
The first pair of legs is long and robust, typically featuring 'brushes' or tufts of feathers (setae). They use a specialized structure called a calamistrum to card their silk into a 'hackled' texture.
Venom & Safety Information
Venom Information
Non-venomous. Members of the family Uloboridae are among the only spiders in the world that completely lack venom glands.
Medical Significance
None. They cannot bite effectively and have no venom to inject. They are completely harmless to humans and pets.
Safety Recommendations
No safety precautions are necessary. If found on clothing or bedding, they can be gently brushed off or moved outside using a piece of paper.
Habitat & Behavior
Habitat & Range
Common throughout North America, particularly in the Eastern and Central United States. Found in gardens, woods, and frequently near human dwellings in sheltered areas.
Behavior & Temperament
Extremely docile and shy. Because they lack venom, they rely entirely on wrapping prey tightly in massive amounts of silk for immobilization. They often play dead or drop from the web when disturbed.
Diet & Prey
Small flying insects like gnats, fruit flies, and small moths. They wrap prey in hundreds of meters of fine silk to crush and predigest it.
Seasonal Activity
Most active from late spring through early autumn. Often overwinter as egg sacs or juveniles in sheltered cracks.
Description
An inconspicuous but fascinating spider, the Feather-legged Orb-weaver is a master of camouflage. Often mistaken for a bit of lint or a twig, it rests in a unique posture with its long front legs extended forward. It is a biological oddity due to its lack of venom.
Key Features
Feather-like tufts on the first pair of legs, a humped abdomen, and the habit of resting with front legs held together and extended forward.
Similar Species
Tetragnatha (Stretch spiders), which are longer and thinner, and Cyclosa (Trash-line orb-weavers), which build vertical webs and incorporate debris.
Life Cycle
Females produce distinctive papery, star-shaped or flattened egg sacs which they guard. Lifespan is typically one year, with activity peaking in late summer.
Ecological Importance
Excellent for indoor and garden pest control, specifically targeting small nuisance flies.
Conservation Status
Not evaluated by IUCN; however, they are common and widespread with stable populations.
Interesting Facts
Unlike most spiders that use 'glue' on their webs, these spiders use 'hairy' silk that entangles the bristles and limbs of insects like Velcro.
Photography Tips
Due to their small size, a macro lens is essential. Focus on the 'feather' tufts on the front legs and the humped profile of the abdomen against a plain background.
Identified: 2026-07-07T16:39:44.872395