Tan Jumping Spider, Familiar Jumping Spider
Platycryptus undatus
Salticidae (Jumping Spiders), Order Araneae
Physical Description
A stout, flattened jumping spider adapted for living on vertical surfaces. The body is covered in short, dense hairs that give it a fuzzy appearance. The cephalothorax is broad and the abdomen is somewhat elongated and flattened.
Size Estimate
Adult females range from 10–13 mm in body length; males are slightly smaller at 8–10 mm. Total leg span is typically between 15–25 mm.
Coloration & Markings
Characterized by a mottled pattern of grey, tan, and brown. The abdomen features a prominent, dark undulating or 'V-shaped' pattern (chevron-like) down the center, bordered by lighter shades. These colors provide excellent camouflage against tree bark or weathered wood.
Web Type
This spider does not build a prey-capture web. It is an active hunter. It does, however, construct silken 'retreats' or 'pup tents' in crevices for molting, laying eggs, and overwintering.
Eye Arrangement
A classic Salticid pattern of 8 eyes. Four large eyes are arranged across the front (Anterior Median Eyes being the largest, giving them excellent binocular vision), with smaller eyes located on the sides and top of the cephalothorax for 360-degree motion detection.
Leg Characteristics
The legs are relatively short, thick, and powerful, adapted for sudden leaps. They are covered in fine hairs and exhibit subtle banding. They lack the long spines found on many orb-weavers, instead having dense tarsal claws for gripping smooth surfaces.
Venom & Safety Information
Venom Information
The venom is a mild neurotoxin complex specifically evolved to immobilize small insects. It is not considered toxic or dangerous to humans.
Medical Significance
Low medical significance. A bite may cause minor localized redness or itching similar to a mosquito bite or bee sting. No specialized treatment is usually required other than cleaning the site.
Safety Recommendations
No precautions are necessary. If found indoors, they can be easily relocated by placing a cup over them and sliding a piece of paper underneath. They are beneficial houseguests and pose no threat to pets or children.
Habitat & Behavior
Habitat & Range
Common throughout North America, especially in the Eastern US and Canada. Often found on vertical surfaces such as tree trunks (particularly shaggy bark trees), fences, and the exterior walls of houses.
Behavior & Temperament
Highly intelligent and curious. They use vision to track movement and will often turn their entire body to look at a human observer. They are active diurnal hunters that stalk prey before pouncing. They are generally very docile and rarely bite unless pinned.
Diet & Prey
Primarily small insects such as flies, gnats, moths, and other spiders. They use their exceptional eyesight to stalk prey from a distance, then leap to deliver a bite, often using a silken 'tether' as a safety line.
Seasonal Activity
Active from spring through autumn. Often seen in late fall looking for overwintering sites on house siding. In winter, they remain dormant in silk retreats.
Description
Known as 'the' familiar jumping spider of the eastern United States, this species is a master of camouflage. Often found sunning itself on the side of homes or trees, it is one of the few spiders that seems to show curiosity toward humans, tracking movements with its large, expressive eyes.
Key Features
Flattened body profile; grey/tan mottled coloration; dark wavy (undulated) pattern on the abdomen; distinctively large, forward-facing searchlight eyes.
Similar Species
Plexippus paykulli (Pantropical Jumper) which has more linear stripes; Platycryptus californicus (Western Tan Jumper) found in western regions; and various Menemerus species which are often smaller and darker.
Life Cycle
Females lay eggs in silk sacs within a hidden retreat. Spiderlings emerge and eventually 'balloon' via silk threads to find new territories. They can live up to 1-2 years, often overwintering as sub-adults in group silken cocoons.
Ecological Importance
Crucial for natural pest control around homes and in gardens, consuming large numbers of nuisance insects like flies and mosquitoes.
Conservation Status
Not evaluated by IUCN, but considered common and widespread with stable populations in urban and rural environments.
Interesting Facts
Despite their small size, they have some of the best vision among all invertebrates. They are capable of jumping 10 to 50 times their body length. Research suggests they can remember specific locations within their habitat.
Photography Tips
Focus primarily on the face to capture the large eyes. Use a macro lens or 'portrait mode' on a smartphone. They are often curious, so moving slowly will allow you to get close-up shots as they watch the camera lens.
Identified: 2026-05-26T16:22:47.352731