Encountering a pale spider can spark immediate questions about its nature and potential danger. While true albinism is exceedingly rare in spiders, several species naturally exhibit white or very light coloration, leading to this common misconception. This article explores the biological realities behind white spiders and addresses concerns about their venom.
Understanding White Spiders
True albinism, a genetic condition, is characterized by a complete absence of melanin, resulting in white skin or hair and often red or pink eyes due to visible blood vessels. This condition is rare in spiders because arachnids primarily use pigments other than melanin for coloration. Most spiders appearing white are not truly albino but rather achieve their pale hue through other biological mechanisms.
A spider’s color is influenced by genetics, diet, age, and environmental conditions. Many white spiders use their pale appearance for camouflage, blending seamlessly with flowers or other light-colored surroundings to ambush prey. Some spiders, particularly after molting, may temporarily appear much lighter before their exoskeletons harden and darken.
Common White Spider Species
Several spider species are naturally white or very pale and are often mistaken for “albino spiders.” Common examples include crab spiders, particularly the goldenrod crab spider (Misumena vatia). These spiders can change color, typically between white and yellow, to match the flowers they inhabit for ambush hunting. They possess a flattened, crab-like body shape and often hold their front two legs outward.
Another group frequently appearing pale are sac spiders, including yellow sac spiders (Cheiracanthium species) and ghost spiders (Anyphaenidae family). Yellow sac spiders are small, 0.2 to 0.4 inches, with legs significantly longer than their bodies. Ghost spiders, typically 4-8 mm, are often pale and nocturnal hunters that do not build webs but rather silken retreats in sheltered spots. These spiders are often found in homes, under rocks, or in leaf litter.
Venom and White Spiders
When discussing spiders, it is important to differentiate between “poisonous” and “venomous.” Spiders are venomous; they inject toxins through a bite. Poisonous organisms are harmful if ingested or touched. Nearly all spiders are venomous, using venom glands and fangs to subdue prey. However, venom potency and its effect on humans vary significantly.
For common white spiders like crab spiders, yellow sac spiders, and ghost spiders, their venom is generally considered mild and not medically significant to humans. A goldenrod crab spider bite, for instance, typically causes a sharp pain similar to a bee sting, with minimal or no lasting effects. Yellow sac spider bites may result in immediate pain, redness, and swelling, which usually resolve within a few days. In rare cases, a slow-healing sore might develop. Ghost spider bites are often described as a pinprick or bee sting, with venom not usually dangerous to humans, sometimes causing short-term swelling.
Encountering White Spiders
If you encounter a white spider, observe it from a safe distance. Most spiders are not aggressive and only bite if threatened or accidentally pressed against skin. To humanely remove a spider from your home, place a cup over it and slide paper underneath to trap it. Then, release the spider outdoors in a sheltered area, like a garden.
Should a bite occur, clean the area with mild soap and water, and apply a cool compress to reduce pain and swelling. Over-the-counter pain relievers or antihistamines can help manage discomfort and itching. Seek medical attention if the bite area becomes severely red, painful, blisters, appears infected, forms an ulcer, or if you experience severe pain, stomach cramping, or difficulty breathing.