Woodlouse Hunter, Sowbug-killer, Woodlouse Spider
Dysdera crocata
Dysderidae (Woodlouse Hunters), Order Araneae
Physical Description
A striking spider with a smooth, glossy texture. It features a cephalothorax (head region) that is dark reddish-brown and highly sclerotized (hardened) with exceptionally large, forward-pointing chelicerae (fangs). The abdomen is ovate, creamy grey to dark tan or even purplish-tan, and lacks hairs or patterns.
Size Estimate
Estimated body length 10-15mm (approx. 0.5 inches), with a leg span reaching up to 25-30mm. This specimen appears to be an adult.
Coloration & Markings
Contrast between a deep mahogany or rusty-red cephalothorax/legs and a pale, greyish-yellow or buff-colored abdomen. There are no stripes or spots; the colors are solid. Young spiderlings look similar but have paler cephalothoraxes.
Web Type
None. This is a wandering hunter that does not use a web for prey capture. They build silken, sac-like retreats in crevices for molting, laying eggs, and daytime resting.
Eye Arrangement
Six eyes (not the usual eight) arranged in a tight semi-circle or oval cluster at the front of the cephalothorax.
Leg Characteristics
Six legs are positioned forward-facing or sideways; the legs are medium-thick, smooth, and orange-red in color, matching the cephalothorax.
Venom & Safety Information
Venom Information
The venom is not considered medically significant to humans. It is designed to paralyze small invertebrates. A bite may cause localized pain similar to a bee sting.
Medical Significance
Low danger level. Bites are rare and usually happen when the spider is accidentally pressed against skin. Symptoms include localized redness, minor swelling, and itching. No specific treatment is required other than cleaning the site.
Safety Recommendations
If found indoors, use a cup and paper to relocate them to a garden or woodpile. Do not handle with bare hands to avoid a defensive bite. Seal cracks in basements to prevent entry.
Habitat & Behavior
Habitat & Range
Commonly found in North America, Europe, Australia, and parts of Asia. They prefer damp, dark areas under logs, rocks, leaf litter, and bricks, or in basements and crawlspaces where their prey lives.
Behavior & Temperament
Strictly nocturnal active hunters. They are generally shy and will retreat, but can be defensive if handled or pinned, using their large fangs to bite.
Diet & Prey
Highly specialized to eat woodlice (sowbugs/pillbugs). Their long, sickle-shaped fangs are designed to reach around and pierce the thick, armored plates of the woodlouse's exoskeleton.
Seasonal Activity
Active year-round in warmer climates or indoors. Outdoors, they are most frequently seen by homeowners in spring and autumn.
Description
The Woodlouse Hunter is an impressive specialist of the undergrowth. With its bicolored body and formidable fangs, it is a master at hunting armored prey that other spiders avoid. Found frequently near human dwellings in gardens or damp areas, it serves as an excellent natural pest controller.
Key Features
Reddish-brown cephalothorax, pale unpatterned abdomen, only six eyes, and exceptionally large protrusive fangs.
Similar Species
Broad-faced sac spiders (Trachelas tranquillus) have similar colors but lack the oversized fangs and have eight eyes. Dysdera erythrina is a smaller European relative.
Life Cycle
Females lay about 70 eggs in a silken sac within their retreat. They exhibit some maternal care, guarding the sac until spiderlings emerge. They can live for 2-3 years.
Ecological Importance
Crucial for controlling populations of woodlice and other soil-dwelling invertebrates. They are a vital link in the food chain of garden ecosystems.
Conservation Status
Not evaluated by IUCN, but considered common and widespread with stable populations due to their ability to adapt to human-altered landscapes.
Interesting Facts
Despite their scary-looking fangs, they are essentially harmless to humans. Their fangs are an evolutionary adaptation specifically for 'cracking' the armor of isopods.
Photography Tips
Focus on the 'face' to capture the six-eye arrangement and the large fangs. Use a macro lens and side-lighting to highlight the glossy texture of the cephalothorax.
Identified: 2026-06-15T10:12:05.906253