Woodlouse Hunter, Sowbug-killer, Woodlouse Spider
Dysdera crocata
Dysderidae (Woodlouse Hunters), Order Araneae
Physical Description
A striking spider with a smooth, glossy cephalothorax and an elongated, oval-shaped abdomen. They are notable for their exceptionally large, forward-projecting chelicerae (fangs) relative to their body size, designed to pierce the heavy armor of woodlice.
Size Estimate
Body length 9–15 mm (excluding legs); leg span approximately 25–40 mm. This appears to be a mature specimen.
Coloration & Markings
Distinctive two-toned appearance: the cephalothorax and legs are a deep reddish-orange to mahogany brown, while the abdomen is a pale, creamy tan, grayish, or yellowish color with a satiny texture. No complex patterns or markings.
Web Type
This is a hunting spider that does not use a web for prey capture. It spins a small, silk, 'sleep sac' or retreat under logs, stones, or in leaf litter for resting and molting.
Eye Arrangement
Unusually, these spiders have only six eyes (most spiders have eight) arranged in a tight semi-circle or cluster towards the front of the head.
Leg Characteristics
The legs are smooth and semi-translucent reddish-orange. They are moderately long and robust, lacking conspicuous spines or thick tufts, evolved for scurrying through narrow crevices.
Venom & Safety Information
Venom Information
The venom is not considered medically significant to humans. It is designed to immobilize small arthropods. Bites may cause localized pain but lack systemic toxins.
Medical Significance
Low danger level. The bite is often described as being similar to a bee sting in intensity—localized redness, swelling, and minor itching are the most common symptoms. No long-term damage or severe reactions are typical.
Safety Recommendations
If found indoors, relocate the spider using a jar and a piece of paper. Wear gloves if handling wood piles or leaf litter where they reside. If bitten, clean the area with soap and water; use a cold compress for swelling.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution; originally from the Mediterranean but now found throughout Europe, North America, Australia, and South America. Commonly found in damp, dark areas like gardens, under rocks, in firewood piles, and occasionally basements.
Behavior & Temperament
A nocturnal, active hunter. They wander at night searching for prey. While they can appear aggressive when cornered by opening their large fangs, they generally prefer to flee. They are solitary and shy.
Diet & Prey
Specialized predators of woodlice (isopods/roly-polies). They use their elongated fangs to reach around and pierce the softer underside of the woodlouse's armored shell. They may occasionally eat other small invertebrates.
Seasonal Activity
Active year-round in milder climates, but most frequently encountered indoors during late summer and autumn as they seek damp environments or mates.
Description
This is a specialized nocturnal hunter easily recognized by its 'baked bean' colored abdomen and deep red front. It plays a vital role in garden ecosystems by managing populations of wood-boring and decomposing isopods.
Key Features
Reddish-orange cephalothorax, cream-colored abdomen, six eyes, and disproportionately large fangs.
Similar Species
Broad-faced Sac Spiders (Trachelas tranquillus) have similar colors but smaller fangs and eight eyes. Brown Recluses have a violin shape and different eye arrangement.
Life Cycle
Females lay about 70 eggs in a silk sac within their retreat. They exhibit some maternal care, staying with the eggs until they hatch. Individuals can live for 2 to 3 years.
Ecological Importance
Highly beneficial in gardens as they provide natural pest control for woodlice and other ground-dwelling invertebrates, helping maintain the balance of decomposing organic matter.
Conservation Status
Not evaluated by the IUCN, but populations are stable and widespread globally.
Interesting Facts
Despite their frighteningly large fangs, they are almost entirely harmless to humans. Their fangs evolved specifically to bypass the 'armor' of woodlice, which few other spiders can penetrate.
Photography Tips
A macro lens is necessary to capture the unique six-eye arrangement. Focus specifically on the large chelicerae (fangs) and the junction between the red head and tan abdomen.
Identified: 2026-05-04T22:53:56.779044