Woodlouse Hunter, Woodlouse Spider, Sowbug-killer Spider, Slater Spider
Dysdera crocata
Dysderidae (Woodlouse Hunters), Order Araneae. Key family traits include having only six eyes and very large, forward-jutting chelicerae (fangs).
Physical Description
A medium-sized spider with a smooth, hairless appearance. The cephalothorax is oval and shiny, while the abdomen is cylindrical or egg-shaped with a satiny texture. Most notably, it possesses exceptionally large, pincer-like chelicerae that slant forward, adapted for piercing the armor of crustaceans.
Size Estimate
Body length: 11-15 mm for females, 9-10 mm for males. Leg span: approximately 25-40 mm. This specimen appears to be an adult.
Coloration & Markings
Characterized by a distinct bi-color appearance: the cephalothorax and legs are a deep mahogany red or orange-brown, while the abdomen is a pale grayish-beige, creamy yellow, or tan. It lacks any intricate patterns or markings.
Web Type
This is a wandering hunter that does not use a web for prey capture. It constructs a small, silk-lined retreat or 'sac' in crevices for resting and molting.
Eye Arrangement
Unusual for spiders, it has only 6 eyes (most have 8). They are arranged in a tight semi-circular or oval cluster near the front of the cephalothorax.
Leg Characteristics
The legs are moderately long, spindly, and matching the reddish-orange color of the cephalothorax. They appear smooth and lack the heavy spines found on many other hunting spiders.
Venom & Safety Information
Venom Information
The venom is not considered medically significant to humans. While the large fangs can easily pierce human skin, the venom is tailored for woodlice and typically causes only localized effects.
Medical Significance
Low danger level. A bite usually causes immediate, sharp pain (due to mechanical fang size) followed by localized redness, itching, or minor swelling that resolves within a few hours. No systemic toxicity is reported.
Safety Recommendations
These spiders are beneficial and should be left alone. If one enters a home, it can be safely relocated using the 'cup and paper' method. Wear gloves if gardening in damp areas to avoid accidental 'defensive' nips.
Habitat & Behavior
Habitat & Range
Originating from the Mediterranean, it is now globally widespread including North America, Europe, and Australia. Commonly found under logs, rocks, leaf litter, and in damp basements or gardens where woodlice are abundant.
Behavior & Temperament
A nocturnal specialist hunter. It is generally shy and avoids humans, but it can be defensive if handled or pinned. Its aggressive appearance is a byproduct of its hunting niche, not its temperament toward people.
Diet & Prey
Specializes almost exclusively on woodlice (pillbugs and sowbugs). The oversized fangs are designed to reach around or pierce through the woodlouse's hard exoskeleton.
Seasonal Activity
Active year-round in temperate climates, though they are most frequently encountered by homeowners in spring and autumn when they wander in search of mates or humidity.
Description
An unmistakable spider featuring a striking contrast between its blood-red head and creamy abdomen. As a dedicated nocturnal predator, it roams damp environments at night, using its specialized 'pincer' fangs to overcome armored prey.
Key Features
Red/orange cephalothorax and legs; creamy/beige abdomen; exceptionally large forward-projecting fangs; only six eyes.
Similar Species
Often confused with the Broad-faced Sac Spider (Trachelas tranquillus), which has shorter fangs and different eye arrangements, or the Brown Recluse, though Dysdera lacks the violin marking and has a very different body color.
Life Cycle
Females lay about 70 eggs inside a silk retreat. Unlike many other spiders, they do not produce a distinct egg sac but rather a loose cluster. They are relatively long-lived, sometimes reaching 2-3 years of age.
Ecological Importance
Provides excellent natural pest control in gardens and greenhouses by keeping populations of woodlice and other soil-dwelling invertebrates in check.
Conservation Status
Not evaluated by the IUCN, but considered common and stable throughout its global range due to its adaptability to human-altered environments.
Interesting Facts
The woodlouse hunter is an example of an 'evolutionary arms race'—it evolved giant fangs specifically to penetrate the tough armor plates that protect pillbugs from other predators.
Photography Tips
Focus on the 'face' to capture the massive chelicerae and the tight cluster of six eyes. A top-down shot is best for showing the contrast between the red head and pale abdomen.
Identified: 2026-06-15T01:21:54.042167