Tan Jumping Spider, Familiar Jumping Spider
Platycryptus undatus
Salticidae (Jumping Spiders), Order Araneae
Physical Description
A stout, flattened jumping spider with a compressed body shape adapted for hugging tree bark. It has a broad cephalothorax and an elongated oval abdomen, covered in short, dense hairs that provide a fuzzy appearance.
Size Estimate
Body length 8–13 mm (females are larger than males); leg span approximately 15–20 mm. This specimen appears to be an adult or sub-adult.
Coloration & Markings
Mottled brown, gray, and tan. The abdomen features a prominent grayish-white undulating or 'V' shaped chevron pattern down the center. Males typically feature a distinctive orange or reddish band below the eyes.
Web Type
Does not build hunting webs. It uses silk to create small, thick-walled 'pup-tents' or silken retreats for molting, mating, and overwintering.
Eye Arrangement
Typical Salticid pattern: 8 eyes in three rows. Two massive Anterior Median Eyes (AME) provide high-resolution binocular vision, flanked by smaller Anterior Lateral Eyes (ALE). Four smaller eyes are located further back on the cephalothorax.
Leg Characteristics
Relatively short, thick, and powerful legs designed for jumping. They are densely hairy with dark banding. The front legs are often held forward and are slightly more robust for grasping prey.
Venom & Safety Information
Venom Information
Possess a complex venom used to quickly paralyze insect prey. The venom is not considered potent against humans and typically only causes localized effects.
Medical Significance
Harmless to humans. Bites are rare and comparable to a mild bee sting, usually resulting in minor redness or swelling that fades quickly. No special medical treatment is typically required.
Safety Recommendations
If found indoors, they can be easily relocated by placing a cup over them and sliding a piece of paper underneath. Do not use pesticides, as they are beneficial and non-aggressive.
Habitat & Behavior
Habitat & Range
Found throughout Eastern North America. Prefers vertical surfaces like tree trunks, fence posts, and the exterior walls of houses (hence the name 'Familiar').
Behavior & Temperament
Active diurnal hunters with extremely high intelligence for an arthropod. They are curious and alert, often turning to look directly at humans. They are very docile and rarely bite unless pinned.
Diet & Prey
Generalist predators of small insects including flies, crickets, and leafhoppers. They hunt by stalking prey until close enough to execute a precise, high-speed leap.
Seasonal Activity
Most active from late spring through autumn. Large numbers of adults may congregate to overwinter together in communal silken retreats under loose bark.
Description
The Tan Jumping Spider is a charismatic, fuzzy arachnid known for its incredible eyesight and inquisitive nature. Unlike many spiders that hide in webs, this species is a visible part of the garden and home ecosystem, often seen patrolling sunlit walls or bark for its next meal.
Key Features
Compressed/flattened body profile; undulating 'V' shaped patterns on the abdomen; large, forward-facing 'puppy-dog' eyes; mottled tan and gray coloration.
Similar Species
Platycryptus californicus (found in the West) and various species of Marpissa, which are generally more elongated and lack the specific undulating abdomen pattern.
Life Cycle
Females lay eggs in a silken sac within their retreat and guard them until 1-2 weeks after hatching. Spiderlings disperse via 'ballooning' on silk threads. They typically live for about 12-18 months.
Ecological Importance
Excellent biological pest control, consuming significant numbers of garden pests and indoor nuisance insects like flies and gnats.
Conservation Status
Common and widespread; not currently listed as a species of concern. Adapts well to human-modified environments.
Interesting Facts
Despite their small size, they have vision capabilities that rival some small mammals. They use silk 'draglines' as a safety tether before jumping, similar to a bungee cord.
Photography Tips
Focus specifically on the large front eyes to capture the spider's 'personality.' Use a macro lens or phone macro mode and provide plenty of natural light to bring out the texture of the hairs.
Identified: 2026-07-08T20:53:46.124712