Oregon is home to large, tarantula-like spiders, though they are not the “true” tarantulas (Theraphosidae family) popular in the pet trade and found in the southwestern United States. These substantial, burrowing spiders are often mistaken for tarantulas due to their size and appearance, but are scientifically classified differently while sharing some characteristics.
Oregon’s Native Tarantula-like Species
The primary large, burrowing spider native to Oregon that resembles a tarantula is the Pacific folding-door spider (Antrodiaetus pacificus). These mygalomorphs, from the family Antrodiaetidae, possess fangs that point downwards and parallel to each other, unlike the pincer-like fangs of most other spiders.
Female Antrodiaetus pacificus typically measure between 11 to 13 millimeters in body length, with males being slightly smaller. Their coloration ranges from dark brown to almost black, sometimes with a purplish-brown abdomen. Males have long legs, slender bodies, and three hardened plates (tergites) on their abdomen, while females are more robust with only one tergite.
Where Tarantula-like Spiders Reside in Oregon
Pacific folding-door spiders are found throughout the Pacific Northwest, from San Francisco Bay to Alaska. They inhabit cool, damp forest environments, constructing burrows in soft substrates like sand, moss, or decaying wood. These spiders excavate vertical shafts that can be six to ten inches deep.
Their burrows are lined with silk, which extends beyond the ground level as a camouflaged collar. The entrance is often sealed with a “folding door” made of silk and soil, allowing the spider to remain hidden. This burrow system serves as both a habitat and a hunting ground, protecting the spiders from predators and harsh weather while providing a strategic ambush point for prey.
Encountering an Oregon Tarantula-like Spider
Pacific folding-door spiders are reclusive, spending most of their lives within their burrows. They are primarily nocturnal hunters, emerging at night to ambush passing insects near their burrow entrance. If prey, such as a beetle, moves close, the spider rapidly emerges to seize it.
These spiders are not considered a threat to humans and are harmless. While they possess fangs, a bite from an Antrodiaetus pacificus is not medically significant. If threatened, a female might display a defensive posture by rearing back with her fangs and front legs extended. However, they are not aggressive and prefer to retreat or defend themselves rather than bite.