Tan Jumping Spider, Flatties
Platycryptus undatus
Salticidae (Jumping Spiders), Order Araneae. Key family characteristics include large, forward-facing anterior median eyes providing exceptional stereoscopic vision, and a specialized internal hydraulic mechanism that allows them to jump distances many times their body length.
Physical Description
Compact, robust body with a flattened profile designed for slipping into narrow crevices. The cephalothorax is broad and high-fronted, while the abdomen is oval and slightly elongated. They are covered in fine, dense setae (hairs) that give them a somewhat fuzzy appearance.
Size Estimate
Body length typically ranges from 8 to 13 millimeters for females and slightly smaller for males, with a total leg span roughly matching the body length. This specimen appears to be an adult or sub-adult.
Coloration & Markings
Mottled pattern of grayish-brown, tan, black, and white scales providing excellent camouflage against tree bark and weathered wood. Features characteristic wavy transverse bands across the abdomen and distinct white markings around the large anterior eyes.
Web Type
Jumping spiders do not spin webs to catch prey. Instead, they construct small, silken retreat sacs under loose bark, in crevices, or on structural surfaces where they rest at night, molt, and lay eggs.
Eye Arrangement
Typical salticid arrangement of eight eyes in three rows. The anterior median eyes are exceptionally large and prominent, capable of high-resolution color vision. Two smaller lateral eyes sit beside them, and four smaller eyes are positioned on the rear portion of the cephalothorax.
Leg Characteristics
Short to medium-length, robust legs equipped with dense scopulae (pads of fine hairs) and claw tufts that allow them to adhere effortlessly to vertical glass and smooth surfaces. Legs are distinctly banded with dark and light markings and held in a compact, ready-to-spring posture.
Venom & Safety Information
Venom Information
Possesses mild neurotoxic venom used primarily to immobilize small invertebrate prey. The venom is harmless to humans and large pets.
Medical Significance
Not medically significant. Bites are extremely rare, non-toxic, and typically cause no more than a mild, temporary localized redness or itching similar to a mosquito bite.
Safety Recommendations
No special precautions needed. If relocation is desired, place a small cup over the spider and slide a piece of paper underneath to carry it outdoors.
Habitat & Behavior
Habitat & Range
Found widely across eastern North America. Prefers arboreal habitats such as deciduous forests and wooded areas, frequently found on tree trunks, wooden fences, and exterior walls of rural and suburban homes.
Behavior & Temperament
Active diurnal hunter relying on acute vision rather than webs to locate prey. Inquisitive and alert, often turning to look at human observers. Highly docile and rarely bites unless trapped directly against the skin.
Diet & Prey
Carnivorous generalist feeding on a wide variety of small insects, including flies, mosquitoes, aphids, and other spiders. Stalks prey cautiously before executing a precise, lightning-fast leap to capture it.
Seasonal Activity
Most active during spring and summer months during daylight hours. Overwinters by retreating into protected silken cocoons tucked beneath loose bark or siding.
Description
The tan jumping spider is a charismatic and harmless visitor to walls, fences, and tree bark. With its flattened body, mottled camouflage, and oversized, intelligent-looking eyes, it represents one of nature's most accomplished visual hunters. Rather than spinning webs, it actively stalks and pounces on insect pests, making it a welcome guest in any garden or home.
Key Features
Flattened body profile, mottled gray-and-tan coloration with wavy abdominal bands, very large and expressive forward-facing eyes, and agile, leaping locomotion.
Similar Species
Other gray or brown jumping spiders such as Platycryptus californicus in the west, or species within the genus Phidippus, which are generally larger, rounder, and more vibrantly colored.
Life Cycle
Females construct silken egg sacs in hidden retreats, guarding the eggs until hatching. Spiderlings disperse via ballooning or active crawling. They undergo multiple molts over a one-to-two-year lifespan.
Ecological Importance
Acts as an effective natural pest control agent by actively consuming large numbers of nuisance insects and mosquitoes. Serves as a vital prey item for insectivorous birds and small reptiles.
Conservation Status
Secure and widespread throughout its native range. Not evaluated by the IUCN, with stable populations facing no significant threats.
Interesting Facts
Tan jumping spiders can jump up to 50 times their own body length using a sudden increase in blood pressure to extend their rear legs. Their visual acuity rivals that of a cat, allowing them to perceive color and movement across significant distances.
Photography Tips
Use a macro lens in bright natural light to capture the iridescent sheen and fine details of the large anterior eyes. Approach slowly to avoid triggering an escape jump.
Identified: 2026-08-07T19:13:13.499665