Grass spiders, common inhabitants across North America, often spark curiosity regarding their physical dimensions and whether they pose any danger. These arachnids are frequently encountered in various outdoor settings.
Their Measured Size
Grass spiders vary in size between sexes, with females typically larger than males. Female grass spiders usually have a body length ranging from 0.39 to 0.78 inches (10 to 20 millimeters). Males are slightly smaller, generally measuring around 0.31 to 0.70 inches (9 to 18 millimeters) in body length. Their long, slender legs can contribute to a larger perceived size, with their leg span potentially reaching up to 1.5 inches (38 millimeters).
Key Identification Features
Grass spiders possess two prominent spinnerets at the rear of their abdomen, which are noticeably long and can appear like small tails. Their body shape is elongated and slender, sometimes appearing slightly flattened. They commonly display yellowish-brown, light brown, gray, or tan coloration. The carapace often features two dark longitudinal stripes parallel to a lighter middle band, and the abdomen frequently has a pattern of dark chevron markings. They have eight small eyes, usually arranged in two curved rows.
Common Habitats
Grass spiders primarily inhabit outdoor environments, where they construct distinctive webs. They are frequently found in grassy areas, lawns, meadows, fields, gardens, and shrubbery. Their characteristic webs are funnel-shaped, appearing as a sheet-like structure laid horizontally with a narrow, funnel-like retreat at one end.
These webs are often built close to the ground, nestled within dense vegetation, under rocks, or near structures such as fences and building foundations. Unlike some other spiders, their webs are not sticky, relying on the spider’s speed to capture prey. Grass spiders may occasionally venture indoors, particularly males searching for mates or when outdoor conditions become colder.
Assessing Their Threat
Grass spiders, while venomous, are not considered dangerous to humans. Their fangs are small, making it difficult for them to penetrate human skin. The venom they produce is primarily adapted for immobilizing and digesting insect prey.
Should a bite occur, symptoms are mild and localized, including redness, slight pain, swelling, and itching at the bite site. These reactions subside quickly and can be managed with basic first aid, such as cleaning the area with soap and water and applying a cold compress. Serious systemic reactions are rare. Grass spiders are not aggressive and will only bite if they feel threatened or provoked.