Tan Jumping Spider, Familiar Jumping Spider
Platycryptus undatus
Family Salticidae (Jumping Spiders), Order Araneae
Physical Description
A medium-sized, flattened jumping spider with a somewhat rectangular cephalothorax and an elongated, leaf-shaped abdomen. The body is densely covered in short hairs that provide a velvet-like texture, which aids in camouflage against tree bark.
Size Estimate
Adult females range from 10-13 mm in body length; males are slightly smaller at 8-10 mm. This specimen appears to be an adult based on the prominent chevron markings and body proportions.
Coloration & Markings
Characterized by a base of mottled greys, browns, and tans. The most striking feature is the dorsal abdominal pattern consisting of a pale, wavy or 'zig-zag' central band (folium) bordered by darker brown or black edges. This 'undulating' pattern gives the species its name.
Web Type
Does not build a hunting web. As a member of the Salticidae family, it uses silk only for building silken 'retreats' or pup tents for molting, sleeping, and protecting egg sacs, and for 'draglines' while jumping.
Eye Arrangement
Features four pairs of eyes with the anterior median eyes (AME) being exceptionally large and forward-facing, providing high-resolution binocular vision. The remaining eyes are arranged in a U-shape on the cephalothorax, providing nearly 360-degree motion sensing.
Leg Characteristics
The first pair of legs is notably thicker and stronger, used for grasping prey. All legs are relatively short, stout, and covered in fine hairs and light/dark banding. They lack the long, spindly look of web-weaving spiders.
Venom & Safety Information
Venom Information
Produces a mild venom used to immobilize small insects. The venom is not considered medically significant to humans; it is complex and specialized for invertebrate nervous systems.
Medical Significance
Harmless. A bite is rare and typically occurs only if the spider is pinched against skin. Symptoms are usually less severe than a bee sting, involving minor localized redness or itching that subsides quickly.
Safety Recommendations
No special safety measures required. If found indoors, they can be easily relocated by placing a cup over them and sliding a piece of paper underneath to carry them outside.
Habitat & Behavior
Habitat & Range
Common throughout North America, particularly east of the Rockies. They are frequently found on vertical surfaces such as tree trunks, fence posts, and the exterior walls of houses (hence 'Familiar' jumping spider).
Behavior & Temperament
Active diurnal hunters with extremely high intelligence for an arthropod. They are inquisitive and often track human movement with their large eyes. They are docile and very reluctant to bite, usually choosing to jump away if threatened.
Diet & Prey
Generalist predators of small insects including flies, crickets, and moths. They track prey visually, stalk it until within range, and then leap several times their body length to pin the prey down.
Seasonal Activity
Most active from late spring through autumn. During winter, they overwinter as sub-adults or adults inside thick silken retreats hidden in cracks or under bark.
Description
The Tan Jumping Spider is a charismatic resident of many North American backyards. Unlike the skittish house spiders found in corners, this species is a visual predator that seems to 'interact' with its environment. Its flattened body and intricate grey patterns make it a master of disguise on wooden surfaces.
Key Features
Distinctive wavy/undulating pale band on the abdomen; flattened body profile; exceptionally large forward-facing eyes; hairy tan and grey coloration.
Similar Species
Platycryptus californicus (found in western North America) and various species of the genus Marpissa, which tend to have more elongated bodies and different abdominal patterns.
Life Cycle
Females lay eggs in silken sacs hidden in crevices or under bark during summer. They exhibit maternal care by guarding the sac until spiderlings emerge. Life expectancy is typically around one to two years.
Ecological Importance
Serves as an efficient natural pest controller, consuming large numbers of flies and household pests. They are also a food source for birds and predatory wasps.
Conservation Status
Not evaluated by the IUCN, but considered common and widespread with stable populations in urban and rural environments.
Interesting Facts
Jumping spiders have the best vision of any terrestrial invertebrate. P. undatus is known to be particularly 'friendly,' often jumping onto human observers out of curiosity rather than aggression.
Photography Tips
Focus on the anterior median eyes to capture the 'personality' of the spider. Use a macro lens and high shutter speed, as they move in quick, jerky bursts. Side profiles are best for showing their flattened shape.
Identified: 2026-07-19T18:44:44.092092