A common misconception suggests spiders actively “chase” humans. Spiders do not pursue humans with aggressive intent; they are not interested in humans as prey, nor do they view people as a threat. Understanding their actual behavior can help demystify these arachnids.
The Reality of Spider Movement
Spider movements are primarily driven by fundamental survival instincts. Their concerns involve finding food, locating shelter, or escaping danger. Spiders are not evolved to prey on large animals like humans; their diet consists of much smaller invertebrates. Therefore, a spider’s movement towards a person is never an intentional pursuit for food.
Most spiders have limited sensory capabilities, particularly concerning vision. While they often have multiple eyes, many species have poor eyesight, primarily detecting differences in light, dark, and motion. They rely on other senses, such as vibrations, air currents, and chemical signals, to navigate their environment and locate prey. Their legs are equipped with sensitive hairs that pick up minute vibrations from the ground or air, which are crucial for sensing their surroundings.
Spiders move using a unique hydraulic system, extending their legs by increasing fluid pressure within their bodies. Muscles are primarily used for flexing their legs, while hydrostatic pressure facilitates extension. This enables them to perform a variety of movements, from slow crawls to rapid bursts of speed, depending on their needs. When startled, their instinct is often to find immediate cover, which may lead to seemingly erratic movements.
Why Spiders Approach
What appears to be a spider “chasing” a human is a misinterpretation of its natural reactions. When a spider senses movement or vibrations from an approaching human, it perceives a large presence. This triggers an instinctive panic response, prompting the spider to seek immediate refuge. Their poor eyesight means they may not distinguish a human from a large, dark object, and they might dart towards it as a potential hiding spot.
A spider may also lunge defensively if it feels cornered or threatened. This is not an act of aggression but a self-defense mechanism. For instance, if a spider is accidentally pressed against skin or trapped in clothing, it may bite out of fear. Such bites are defensive and rare, as spiders prefer to flee rather than confront a threat.
Sometimes, a spider’s rapid movement in a person’s direction is a coincidental escape path. Spiders explore new environments with quick bursts of movement, and their scurrying can unintentionally lead them towards a person. They may also be drawn to vibrations that mimic insect prey, activating their predatory response. These behaviors are instinctual reactions to their surroundings, not deliberate pursuits of humans.
Spiders with Quick Movements
While no spiders truly “chase” humans, some species are known for their speed. Wolf spiders, for example, are active hunters that do not build webs to catch prey. They use their agility and speed to stalk and pounce on prey. They can move up to 2 feet per second in short bursts. This speed is an adaptation for catching fast-moving insects or escaping predators, not for pursuing people.
Australian funnel-web spiders are also known for their speed and defensive postures. When confronted, they may rear up and display their fangs, a warning signal to deter threats. Their speed enables them to move quickly within their burrows or when encountering prey. These behaviors are defensive, rather than aggressive attacks on humans.
Camel spiders, also called solifuges or sun spiders, are arachnids often mistaken for true spiders. They are very fast, capable of speeds up to 10 miles per hour. Their rapid movement towards a person is an attempt to seek shade from the sun, as they inhabit hot desert climates. They are not venomous to humans, but their powerful jaws can inflict a painful pinch.
Encountering Spiders Safely
Encountering a spider can be startling, but most spiders found in homes are harmless to humans. Out of over 50,000 known spider species globally, only a small number have medically significant venom. The majority of spiders are beneficial, acting as natural pest control by preying on other insects. Understanding their behavior helps reduce fear and promotes safe coexistence.
If a spider is found indoors, safe methods can be used for relocation. Gently placing a cup over the spider and sliding a piece of paper underneath allows for capture and release outdoors. Avoid provoking spiders, as bites occur when they feel threatened or trapped. Preventative measures like sealing cracks, maintaining cleanliness, and reducing clutter can help deter spiders from entering indoors.