Tan Jumping Spider, Undating Spider, Familiar Jumping Spider
Platycryptus undatus
Salticidae (Jumping Spiders), Order Araneae. Key characteristics include high visual acuity and a distinctive rectangular cephalothorax.
Physical Description
A stout, somewhat flattened jumping spider. It features a broad cephalothorax and an elongated oval abdomen. The body is densely covered in short hairs, giving it a fuzzy appearance. The female is typically larger and more robust than the male, which possesses more elongated pedipalps.
Size Estimate
Body length ranging from 8mm to 13mm for females, with males slightly smaller (5mm to 10mm). Leg span is relatively compact, usually under 20mm. This specimen appears to be an adult female.
Coloration & Markings
The primary coloration is a mottled tan, gray, and brown mix that provides excellent camouflage against bark. The most diagnostic feature is a grayish-white 'V' or chevron-shaped pattern running down the center of the abdomen, bordered by darker undulating margins. The face often features a pale horizontal band below the eyes.
Web Type
They do not build hunting webs. Instead, they are active pursuit hunters. They do construct small silk 'retreats' or pupentacular sacs for molting, laying eggs, and sleeping.
Eye Arrangement
Four pairs of eyes with the Anterior Median Eyes (AME) being massively enlarged and forward-facing, providing telephoto-like vision. The other eyes are arranged around the cephalothorax to provide a near 360-degree field of view.
Leg Characteristics
Medium-length, thick, and powerful legs designed for jumping. The front legs are slightly heavier for grasping prey. Legs are covered in fine hairs and mottled with brown and tan banding.
Venom & Safety Information
Venom Information
Contains complex proteins designed to paralyze small insects. However, the venom is not considered medically significant to humans and is very mild in potency.
Medical Significance
Harmless to humans. Bites are extremely rare and usually only occur if the spider is pinched or crushed. Symptoms are typically less severe than a bee sting, involving minor localized redness or itching.
Safety Recommendations
No special precautions are needed. If found indoors, they can be easily moved outside by placing a cup over them and sliding a piece of paper underneath. They are beneficial to have around homes due to their diet.
Habitat & Behavior
Habitat & Range
Widely distributed across North America, especially in the Eastern and Central United States and Southeastern Canada. They are commonly found on vertical surfaces like tree trunks, fence posts, and the exterior walls of houses.
Behavior & Temperament
Highly intelligent and curious. They are diurnal hunters that use their exceptional vision to track prey from a distance before pouncing. They are docile and rarely bite humans, often showing inquisitive behavior toward observers.
Diet & Prey
Carnivorous; feeds primarily on small insects such as flies, moths, and aphids. They utilize a 'stalk and pounce' method, often securing themselves with a silk safety line (dragline) before jumping.
Seasonal Activity
Most active from spring through autumn. In colder climates, they overwinter as sub-adults or adults inside silk retreats hidden in protected crevices.
Description
The Tan Jumping Spider is a charismatic resident of the backyard ecosystem. Unlike many spiders that hide in webs, Platycryptus undatus is an active, visible hunter that relies on stealth and agility. Its mottled colors allow it to vanish against a wooden fence or tree trunk, while its large, puppy-like eyes make it one of the more 'personable' arachnids for enthusiasts to observe.
Key Features
Undulating or chevron pattern on the abdomen; flattened body shape; large forward-facing eyes; tan/gray mottled coloration; preference for vertical man-made or wooden surfaces.
Similar Species
Menemerus bivittatus (Gray Wall Jumper) which has a more distinct dark stripe along the side; Phidippus audax (Bold Jumper) which is usually black with iridescent chelicerae.
Life Cycle
Females lay egg sacs inside silk retreats, often under bark or in crevices. They exhibit maternal care by guarding the sac until the spiderlings emerge. Lifespan is approximately one to two years.
Ecological Importance
Significant natural pest control, consuming a variety of garden and household pests. They serve as a food source for birds and larger predatory insects.
Conservation Status
Not evaluated (NE) by the IUCN, but considered common and stable throughout its range with no immediate threats.
Interesting Facts
They have better vision than many animals many times their size. They are known to 'investigate' humans by looking up at them and following movements, a trait rare among invertebrates.
Photography Tips
Focus specifically on the large central eyes to capture 'eye contact.' Side profile shots are best for showing the abdominal pattern. Use a macro lens or high-resolution close-up mode as they are small but often sit still for long periods.
Identified: 2026-05-26T16:06:37.608693