Dark Fishing Spider
Dolomedes tenebrosus
Pisauridae (Nursery Web Spiders), Order Araneae
Physical Description
A large, robust spider with a flattened body and hair-covered surface. It possesses long, powerful legs and a characteristic mottled appearance that provides excellent camouflage against bark and stone.
Size Estimate
Large; body length typically 15-26mm for females, with a leg span frequently exceeding 3-4 inches (75-100mm). This specimen appears to be an adult.
Coloration & Markings
Displaying a complex pattern of light and dark browns, grays, and blacks. It features prominent 'W' or 'V' shaped dark chevrons on the abdomen and dark ring-like bands on the legs.
Web Type
The Dark Fishing Spider does not build a web for hunting; it is an active ambush predator. Females build a 'nursery web' only after their eggs are close to hatching.
Eye Arrangement
Eight eyes arranged in two rows. The posterior row is slightly curved, and the eyes are relatively uniform in size, providing excellent wide-angle motion detection.
Leg Characteristics
Long, thick, and hairy legs held in a flattened, wide posture. Distinctive dark and light banding (annulations) are present along the entire length of the legs.
Venom & Safety Information
Venom Information
Possesses a complex venom used to immobilize prey. It is not considered medically significant to healthy humans, though it can cause localized pain.
Medical Significance
Low danger level. Bites are rare and usually occur only if the spider is pinched or handled. Symptoms typically include local pain, swelling, and redness similar to a wasp sting.
Safety Recommendations
Use a cup and stiff paper to relocate the spider outdoors. Avoid handling with bare hands to prevent a defensive bite. They are harmless roommates but prefer being outside.
Habitat & Behavior
Habitat & Range
Common across Eastern North America. Unlike other fishing spiders, this species is often found far from water in wooded areas, on tree trunks, and frequently enters homes or outbuildings.
Behavior & Temperament
A shy, nocturnal hunter that relies on speed and camouflage. It is generally non-aggressive toward humans and will attempt to flee rapidly if disturbed.
Diet & Prey
Generalist predator eating insects, other large spiders, and occasionally small vertebrates like minnows or tadpoles if near water. It hunts by sensing vibrations.
Seasonal Activity
Most active from late spring through autumn. Large adults are frequently spotted in late summer during the breeding season.
Description
An impressive and large member of the nursery web spider family, the Dark Fishing Spider is a master of disguise. Often mistaken for wolf spiders, they are distinguished by their larger size and unique leg carriage.
Key Features
Large size, flattened profile, 'W' shaped abdominal markings, and distinct dark bands on the legs. Found frequently indoors or on vertical surfaces like trees.
Similar Species
Often confused with Wolf Spiders (Lycosidae), but can be distinguished by eye arrangement and the lack of a single thick median stripe on the cephalothorax.
Life Cycle
Females carry their large, round egg sacs in their chelicerae (mouthparts). Before hatching, she builds a nursery web in tall grass or foliage to protect the spiderlings.
Ecological Importance
Acts as an important apex invertebrate predator, providing significant natural pest control of large insects like crickets, roaches, and moths.
Conservation Status
Not evaluated by the IUCN, but considered common and stable throughout its range with no major threats.
Interesting Facts
Despite their name, Dark Fishing Spiders are the least 'aquatic' of the genus and are perfectly comfortable living in dry forests and suburban homes.
Photography Tips
Focus on the dorsal (top) pattern of the abdomen and the eyes if possible. Use a flash to highlight the intricate textured hairs on the body.
Identified: 2026-05-13T01:20:18.857293