Jumping spiders (family Salticidae) are widespread arachnids known for their active, diurnal habits and remarkable visual acuity. They are active hunters, using sharp eyesight to stalk and pounce on prey rather than relying on a stationary web. While they possess fangs and venom, they can bite, but such an event is extremely uncommon and poses no significant threat to human health. Their venom is mild and designed to subdue small insects, making any bite medically insignificant.
Identifying Characteristics of Jumping Spiders
Jumping spiders are identified by their distinctive eye arrangement and compact body structure. They possess eight eyes set in three rows, featuring two very large, forward-facing eyes that grant them exceptional stereoscopic vision. This superior eyesight is utilized for navigation, hunting, and complex courtship rituals, allowing them to detect movement up to 18 inches away.
Most jumping spiders are small (1 to 22 millimeters) and have a robust, squat appearance with short, stout legs. Their bodies are often covered in dense hairs or scales that create vibrant, iridescent colors and patterns. Unlike web-spinning spiders, their movements are characterized by short, quick scuttles punctuated by agile, controlled leaps that can cover many times their body length.
The Likelihood and Context of a Bite
Jumping spiders are generally non-aggressive toward humans and prefer to run or leap away when encountering a perceived threat. Their fangs and venom are primarily tools for capturing and immobilizing the small insects and arthropods that make up their diet. Since they do not view humans as prey, a bite occurs only as a defensive measure when the spider feels physically threatened.
The most common scenarios for a bite involve the spider being accidentally trapped or crushed against a person’s skin. This might happen if a spider is pinned down, carelessly handled, or pressed against the body by clothing or bedding. The fangs of many species are quite small and often lack the strength necessary to effectively puncture tough human skin. They prefer to rear up in a defensive posture, raising their front legs, before resorting to a bite.
What Happens After a Bite
If a bite occurs, symptoms are typically mild and localized, as the venom is tailored for insect physiology. People often report an immediate, sharp pain at the site, usually less severe than a common bee sting. This initial sensation is followed by minor, localized reactions such as slight redness, minimal swelling, and an itchy welt.
Symptoms from a jumping spider bite resolve completely within a few hours. Basic first aid involves cleaning the area immediately with soap and water to prevent secondary bacterial infection. Applying a cold compress helps reduce localized swelling and ease discomfort. Seek medical attention only if symptoms worsen after 24 hours or if signs of a rare allergic reaction, such as difficulty breathing, dizziness, or extensive swelling, appear.