Tan Jumping Spider, Familiar Jumping Spider
Platycryptus undatus
Salticidae (Jumping Spiders), Order Araneae. Characterized by high visual acuity and active hunting.
Physical Description
A flattened, stout spider with a rectangular cephalothorax and an elongated oval abdomen. The body is covered in dense, short hairs giving it a fuzzy appearance. This 'flattened' profile is an adaptation for living under tree bark.
Size Estimate
Estimated body length 8-13mm (0.3-0.5 inches). This specimen appears to be an adult or sub-adult female, as they are generally larger and broader than males.
Coloration & Markings
Mottled brown, gray, and tan. The abdomen features a prominent, dark, wavy or zig-zag pattern (chevron) down the center. Males typically have a distinct orange or reddish band below their eyes, which is absent in females.
Web Type
Does not build a hunting web. Instead, it spins a small silken 'pup-tent' retreat for molting, sleeping, and protecting egg sacs. It uses a silk dragline as a safety tether when jumping.
Eye Arrangement
Four pairs of eyes. The Anterior Median Eyes (AME) are very large and forward-facing, providing excellent bifocal vision. The other eyes are arranged around the cephalothorax for 360-degree motion detection.
Leg Characteristics
Relatively short and powerful legs designed for jumping. They are densely hairy with subtle dark banding. The front legs are slightly thicker for grasping prey.
Venom & Safety Information
Venom Information
Possesses a mild venom used to immobilize small insects. The venom is not considered medically significant to humans.
Medical Significance
Harmless to humans. A bite is rare and typically occurs only if the spider is pinched. Symptoms are usually less severe than a bee sting, involving minor localized redness or itching.
Safety Recommendations
No special safety measures required. If found indoors, they can be easily relocated using a cup and a piece of paper. They pose no threat to pets or children.
Habitat & Behavior
Habitat & Range
Found throughout North America, especially in the Eastern United States and Canada. Common on vertical surfaces like tree trunks, fence posts, and the exterior walls of houses.
Behavior & Temperament
Diurnal active hunters. They are highly curious, observant, and known for following human movement with their eyes. They are generally calm and will retreat rather than bite, though they may jump onto hands out of curiosity.
Diet & Prey
Stalks and pounces on prey like a cat. Feeds on a wide variety of small insects, including flies, crickets, and mosquitoes. They use their excellent vision to calculate distance before a terminal leap.
Seasonal Activity
Most active from spring through autumn. Often seen basking on sun-warmed walls in early spring. In late autumn, they seek out crevices for overwintering.
Description
The Tan Jumping Spider is a charismatic, fuzzy arachnid often found patrolling the walls of homes and gardens. Unlike most spiders, it actively 'watches' its surroundings with large, expressive eyes, making it a favorite among nature enthusiasts for its mammal-like curiosity.
Key Features
Flattened body shape; dark wavy/zig-zag pattern on the abdomen; large, forward-facing central eyes; mottled gray/tan fuzzy appearance.
Similar Species
Plexippus paykulli (Pantropical Jumper) has a more distinct central stripe; Menemerus bivittatus (Gray Wall Jumper) has more linear stripes rather than wavy chevrons.
Life Cycle
Females lay eggs in silk retreats, often under bark. They exhibit maternal care, staying with the egg sac until the spiderlings emerge. They typically live for about one year, overwintering in silk shelters.
Ecological Importance
Critical natural pest controllers. They consume significant numbers of flies and mosquitoes around human habitations without the need for chemical pesticides.
Conservation Status
Not evaluated by the IUCN, but considered common and stable throughout its range. No major threats currently identified.
Interesting Facts
Jumping spiders can leap up to 50 times their body length. They have the best vision of any invertebrate, comparable to some small mammals. They are known to 'investigate' humans and can be trained to jump between fingers.
Photography Tips
Focus specifically on the large front eyes to capture the spider's 'personality.' Use a macro lens or portrait mode. Be patient, as they will often turn their heads to look directly at the camera lens.
Identified: 2026-07-14T16:12:37.867915