Woodlouse Spider, Woodlouse Hunter, Pillbug Hunter
Dysdera crocata
Dysderidae (Woodlouse Spider Family), Order Araneae. Key family characteristics include six eyes arranged in a tight, compact cluster on the front of the head and unusually large, projecting chelicerae adapted for piercing hard-shelled prey.
Physical Description
Elongated body with a smooth, shiny, dark reddish-brown to bright orange cephalothorax and legs, contrasting with an elongate, pale gray, beige, or yellowish-pink abdomen. The most striking anatomical features are its enormous, forward-pointing fangs and chelicerae designed specifically to impale armored crustaceans.
Size Estimate
Body length typically ranges from 11 to 15 mm for females and 9 to 10 mm for males, with a leg span around 20 to 25 mm. The specimen appears to be an adult.
Coloration & Markings
Bright, glossy reddish-orange or mahogany head-region and legs with no complex patterns or markings, paired with a plain, unadorned, pale beige-gray or pinkish-tan oval abdomen.
Web Type
Does not build a web to catch prey. Instead, it constructs a silken retreat or daytime refuge under rocks, logs, bark, or in damp soil crevices where it rests during daylight hours.
Eye Arrangement
Six eyes grouped closely together in a tight, compact cluster on the anterior portion of the cephalothorax, typical of the family Dysderidae.
Leg Characteristics
Robust, stout, reddish-orange legs of moderate length, covered with fine hairs and spines, lacking complex banding or patterns. They are adapted for crawling in tight subterranean spaces rather than fast running.
Venom & Safety Information
Venom Information
Contains mild venom used primarily to subdue invertebrate prey. It is not considered dangerous to humans.
Medical Significance
Not medically significant. A bite may cause a brief, sharp pinprick sensation and mild localized redness or swelling, but symptoms typically resolve quickly without medical intervention.
Safety Recommendations
Wear gardening gloves when moving rocks, logs, or mulch in the yard. If found indoors, it can be gently captured with a cup and released outside. No professional pest control is necessary.
Habitat & Behavior
Habitat & Range
Widely distributed globally due to human introduction, commonly found throughout North America, including suburban Utah. Prefers damp, dark microhabitats under rocks, logs, leaf litter, and garden mulch where its preferred prey resides.
Behavior & Temperament
A nocturnal, active hunter that spends daylight hours hiding in a silken sac. It is generally docile and slow-moving, but will bite defensively if trapped or roughly handled against the skin.
Diet & Prey
Specialized feeder that preys almost exclusively on woodlice (pillbugs and sowbugs). Its massive chelicerae are uniquely adapted to pierce the hard, armored exoskeleton of these crustaceans.
Seasonal Activity
Most active during spring and autumn when humidity is higher and woodlice are abundant. They overwinter in sheltered silken retreats beneath the frost line.
Description
The Woodlouse Spider is an easily recognizable garden visitor thanks to its striking color contrast—a glossy, dark red-orange head and legs paired with a pale, sausage-shaped abdomen. Armed with formidable, oversized fangs, this nocturnal hunter is a specialized predator of pillbugs. While its appearance can be intimidating, it is a harmless and beneficial resident of suburban gardens.
Key Features
Glossy reddish-orange cephalothorax and legs, pale beige-gray elongated abdomen, six eyes in a tight cluster, and extremely large, prominent forward-facing chelicerae.
Similar Species
Can be occasionally confused with large ground spiders (Gnaphosidae) or broad-faced sac spiders (Trachelas), but the distinct woodlouse spider coloration and massive forward-facing fangs easily separate it from all lookalikes.
Life Cycle
Females produce a silken egg sac in a protected retreat containing several dozen eggs. After hatching, spiderlings remain with the mother briefly before dispersing. They molt multiple times to reach maturity and can live for several years.
Ecological Importance
Serves as a natural pest control agent in gardens and yards by regulating populations of woodlice, which can sometimes damage tender garden seedlings in high numbers.
Conservation Status
Not evaluated by the IUCN, but populations are secure, widespread, and frequently thrive in human-modified suburban environments.
Interesting Facts
Despite their intimidating fangs, which can pierce human skin, they are completely harmless to people and pets. Their oversized mouthparts are an evolutionary masterpiece designed specifically to slip underneath and pierce the armored plates of roly-polies.
Photography Tips
Photograph from the side or top using macro settings to capture the glossy texture of the cephalothorax and the impressive scale of the chelicerae. Natural diffused light or a ring flash works best to highlight the vibrant red-orange tones.
User Notes
Found in pool suburban Utah
Identified: 2026-08-06T02:55:24.334557