Tan Jumping Spider, Flattied Jumping Spider
Platycryptus undatus
Salticidae (Jumping Spiders), Order Araneae. Characterized by excellent vision, a rectangular cephalothorax, and the ability to leap great distances.
Physical Description
A robust, somewhat flattened body with a truncated, rectangular cephalothorax and an oval-to-tapered abdomen. Covered in fine, dense setae (hairs) giving it a textured, velvety appearance.
Size Estimate
Body length typically ranges from 8 to 13 millimeters, with females generally larger than males. Leg span is roughly 15 to 25 millimeters.
Coloration & Markings
Predominantly shades of gray, tan, and brown with intricate mottled patterns, wavy bands, and lighter salt-and-pepper flecks that provide exceptional camouflage on tree bark and wooden surfaces.
Web Type
Does not build a traditional web to catch prey. Instead, it constructs a silken retreat or nursery sac under loose bark, in crevices, or on siding where it rests at night or during molting.
Eye Arrangement
Typical salticid arrangement featuring eight eyes in three rows: four large forward-facing anterior median eyes providing acute binocular vision, two small lateral eyes behind them, and two medium-sized posterior eyes on the rear corners of the carapace.
Leg Characteristics
Relatively short, stout legs equipped with dense scopulae (hair tufts) for gripping smooth surfaces. Legs feature distinct dark and light banding and are held close to the body in a flattened posture.
Venom & Safety Information
Venom Information
Contains neurotoxic venom used primarily to subdue small invertebrate prey. It is not potent or dangerous to humans.
Medical Significance
Harmless to humans. Bites are exceedingly rare and typically only occur if the spider is directly squeezed or trapped against the skin. Symptoms, if any, are minor and restricted to mild localized redness or swelling similar to a mosquito bite.
Safety Recommendations
No special safety measures are required as these spiders are completely harmless. If relocation is desired, gently guide the spider into a small container using a piece of cardstock and release it outdoors.
Habitat & Behavior
Habitat & Range
Found primarily throughout eastern North America, ranging from Canada down to Florida and west to the Great Plains. Prefers wooded areas, forests, and human structures such as wooden fences, decks, and bark-covered tree trunks.
Behavior & Temperament
An active, diurnal hunter relying on superior eyesight to stalk and pounce on prey rather than using a web. Generally docile, curious, and quick to flee or leap away when disturbed rather than bite.
Diet & Prey
Carnivorous generalist feeding on a wide variety of small insects including flies, mosquitoes, aphids, and moths, captured through a calculated stalking and pouncing technique.
Seasonal Activity
Most active during spring and summer months when warm weather permits hunting. Overwinters as juveniles or adults by sheltering inside dense silken cocoons tucked into protected bark crevices or structural gaps.
Description
The Tan Jumping Spider is a charismatic and harmless visitor often found patrolling wooden fences and tree trunks. With its remarkable jumping ability and large, inquisitive forward-facing eyes, it is a fascinating arachnid that serves as an effective natural pest controller in gardens and around homes.
Key Features
Flattened body profile, grey-tan mottled coloration designed for bark camouflage, large forward-facing median eyes, and a habit of making short, calculated leaps when disturbed.
Similar Species
Other jumping spiders such as Platycryptus californicus or species within the genus Phidippus, distinguished primarily by regional range, subtler gray-brown patterning, and flattened body shape.
Life Cycle
Mates in the spring, after which females construct a silken egg sac containing dozens of eggs hidden under bark or siding. Females often guard the sac until spiderlings emerge. Undergo multiple molts to reach maturity, living for approximately one year.
Ecological Importance
Acts as an efficient biological control agent by consuming large quantities of nuisance insects like flies and mosquitoes, while forming a vital food source for birds and small lizards.
Conservation Status
Not evaluated by the IUCN, but populations are secure, widespread, and common throughout their native range.
Interesting Facts
Tan jumping spiders can leap up to several times their own body length using sudden hemolymph pressure changes in their legs. They are known for turning their heads to look directly at humans with apparent curiosity.
Photography Tips
Use a macro lens in bright natural light (avoiding harsh direct flash) to capture the intricate details of the facial markings and the large, reflective anterior eyes. Approach slowly to avoid triggering a jump.
Identified: 2026-09-11T20:48:03.599741