Barn Spider
Araneus cavaticus
Araneidae (Orb-Weavers), Order Araneae. Characterized by building circular webs and having eight eyes in two rows.
Physical Description
A medium-to-large orb-weaver with a bulbous, slightly triangular abdomen. The abdomen often features two prominent humps (shoulders) near the cephalothorax. The body is covered in fine, short hairs giving it a somewhat fuzzy or velvety appearance.
Size Estimate
Based on the image relative to the doorframe, this is likely an adult female with a body length of 12-22mm. Including the legs, the span is approximately 4-5cm.
Coloration & Markings
Displaying mottled shades of grey, tan, and brown for camouflage. A dark 'folium' (leaf-like pattern) is visible on the dorsal abdomen, bordered by lighter wavy lines. The underside usually features a black patch with two white inverted commas, or 'L' shapes.
Web Type
Large, classic vertical orb-web. They are known for rebuilding their webs almost every night, often near man-made structures with external lighting.
Eye Arrangement
Not clearly visible in the photo, but follows the standard Araneidae pattern of eight small eyes arranged in two rows: four center eyes forming a square and two pairs on the sides.
Leg Characteristics
The legs are relatively thick and possess dark banding or 'socks' at the joints. They are covered in stiff, sensory bristles (macrosetae).
Venom & Safety Information
Venom Information
Contains Typical Araneid venom used for paralyzing insects. It is not considered toxic to humans.
Medical Significance
Low significance. A bite is rare and typically no more painful than a bee sting, resulting in localized redness or minor swelling unless the person has a specific allergy.
Safety Recommendations
Harmless and beneficial. If the web is in an inconvenient spot, gently relocate the spider using a cup and paper to a nearby tree or shrub.
Habitat & Behavior
Habitat & Range
Common across Eastern North America. They prefer shaded, vertical surfaces like barn eaves, porch ceilings, doorways, and cliff faces.
Behavior & Temperament
Primarily nocturnal. They often hide in a crevice during the day and sit at the center of the web at night. They are non-aggressive and will generally drop from the web or retreat if disturbed.
Diet & Prey
Generalist insectivore. They catch flying insects like moths, flies, and beetles. They wrap their prey in silk before delivering a subduing bite.
Seasonal Activity
Most visible in late summer and autumn when they reach adult size and mating occurs.
Description
The Barn Spider is a quintessential architect of the night. Famously associated with E.B. White's 'Charlotte's Web,' these spiders are master weavers that thrive in the interface between human structures and the natural world.
Key Features
Triangular abdomen with shoulder humps, mottled grey/brown camouflage, and dark banding on the legs.
Similar Species
Araneus diadematus (Cross Orb-weaver), which has a distinct white cross on its back, and Neoscona crucifera (Hentz Orb-weaver), which has a more rounded abdomen and different ventral markings.
Life Cycle
Females lay eggs in silk sacs during autumn. The spiderlings hatch in spring. Adults typically live for a single season, dying after the first hard frosts.
Ecological Importance
Excellent natural pest control, consuming significant numbers of mosquitoes and flies near human dwellings.
Conservation Status
Not evaluated by IUCN, but considered common and stable throughout their range.
Interesting Facts
This species inspired the character Charlotte A. Cavatica in 'Charlotte's Web.' They are known to eat their old web at the end of the night to recycle the silk proteins.
Photography Tips
Photograph at night when the spider is active in the center of the web. Use a flash to highlight the dorsal pattern, and try to get a shot of the underside to confirm the 'L' markings.
Identified: 2026-07-08T23:58:25.360701