Tarantulas are large, intimidating spiders whose size and hairy appearance often lead to misidentification. This fascination with big, terrestrial spiders drives many to question whether Washington State, with its diverse geography, provides a suitable environment for these creatures. Understanding the specific biological needs and geographic distribution of tarantulas helps clarify their presence, or lack thereof, in the Pacific Northwest.
Native Tarantulas: The Definitive Answer and Geographic Limits
Washington State does not have any native tarantula species, which belong to the family Theraphosidae. The natural range of North American tarantulas is confined almost exclusively to the arid and semi-arid regions of the Southwestern United States, including Texas, Arizona, and New Mexico. These environments feature the consistently high temperatures and low humidity that these terrestrial, burrowing spiders require for survival. The cold and wet winters of Washington, particularly west of the Cascade Mountains, make the climate inhospitable for native tarantula populations.
Washington is home to the Pacific folding-door spider, Antrodiaetus pacificus, which is sometimes informally referred to as an atypical tarantula. This robust, dark-bodied spider belongs to the infraorder Mygalomorphae, the same group as tarantulas, but is in the separate family Antrodiaetidae. It excavates silk-lined burrows in the soil, which often leads to the occasional misidentification as a true tarantula.
Large Spiders Commonly Found in Washington
The belief that Washington has tarantulas often stems from encountering several large, fast-moving native spider species. The Giant House Spider, Eratigena atrica, is the largest spider in Washington by leg span, with males sometimes reaching up to four inches across. This brown, spindly-legged funnel-web spider is frequently seen indoors, especially when males wander widely during the late summer and fall mating season. Although its size and speed can be alarming, its body is much less robust and hairy than a true tarantula.
The Wolf Spider (family Lycosidae) is another commonly misidentified arachnid. These active, ground-dwelling hunters do not build webs to catch prey and often have a total leg span of up to three inches. Wolf spiders are typically brown or gray with prominent eyes, but they lack the heavy, velvety hair and stocky build characteristic of tarantulas.
What to Do If an Exotic Tarantula Is Encountered
While no tarantulas are native to Washington, it is possible to encounter an exotic specimen that has escaped or been abandoned by a pet owner. These non-native species often originate from warmer climates and pose a risk to the local ecosystem if they establish a population.
If you find a tarantula outdoors, do not handle it; even docile pet species may bite if threatened. The best course of action is to safely contain the spider by placing a large jar or container over it without causing harm. Once secured, contact local animal control or the state’s Department of Fish and Wildlife to report the find. These agencies can advise on the proper capture and disposition of the non-native animal. Releasing an exotic pet into the wild is strongly discouraged because it can introduce disease or disrupt native insect and spider populations. An escaped tarantula will likely seek a dark, moist hiding spot, such as under a porch or in a woodpile.