Huntsman spiders often cause anxiety due to their large size and speed, leading to questions about their presence outside native habitats. Residents of the Great Lakes region frequently wonder if these formidable arachnids have established a population in Michigan. This article provides a definitive answer, exploring the true distribution of Huntsman spiders and identifying the native Michigan species often mistaken for them.
The Definitive Answer: Huntsman Range and Distribution
Huntsman spiders (family Sparassidae) are not native to Michigan and do not have an established, reproducing population in the state. Their geographical distribution is primarily restricted to tropical and warm, temperate regions across the globe, including Australia, Africa, Asia, the Mediterranean Basin, and warmer parts of the Americas. Michigan’s long, cold winters and distinct seasonal temperature changes are incompatible with their ecological requirements. Huntsman spiders require environments that sustain them year-round, which is why they are found in places like Florida and Texas. Any isolated sighting in Michigan results from accidental transport, such as hitchhiking in shipping containers or moving trucks. These individual spiders cannot survive the cold climate long enough to establish a persistent colony.
Spiders Commonly Mistaken for Huntsman Spiders in Michigan
Spiders encountered in Michigan that cause alarm are usually large, native species sharing characteristics like size and speed with the Huntsman.
Dark Fishing Spider
The Dark Fishing Spider (Dolomedes tenebrosus) is one of the largest spiders in the state, sometimes reaching a leg span of over three inches. These brown or grayish spiders are often found near water but also venture into wooded areas and basements, startling homeowners with their size and rapid movement.
Wolf Spiders
Another common misidentification involves large species of Wolf Spiders (family Lycosidae). These hairy, fast-moving spiders actively hunt prey rather than building webs. Wolf spiders are solitary hunters with camouflaged brown, orange, or gray coloring. They are frequently seen running across floors or ground cover, mimicking the quick movements associated with Huntsman spiders.
Giant House Spider
The Giant House Spider (Eratigena atrica), an introduced European species common in the Great Lakes region, is also frequently mistaken for a Huntsman. This funnel-web spider can have a leg span of up to two inches and is known for its speed, often darting from dark corners in basements and garages. Although unnerving due to their size, these native and naturalized spiders are generally harmless to humans and are a normal part of the Michigan ecosystem.
Identifying a True Huntsman Spider
Identifying a true Huntsman spider requires recognizing several distinct physical traits that set them apart from Michigan’s native spiders. Their most distinguishing feature is the laterigrade leg arrangement: the legs are twisted at the base and spread out sideways, giving them a flattened, crab-like stance. This unique arrangement allows them to move laterally with great speed, earning them the nickname “Giant Crab Spiders.” Huntsman spiders also possess a noticeably flattened body shape, an adaptation that lets them squeeze into narrow crevices like under loose bark. While some species reach a leg span of up to six inches, their bodies appear sleek and compressed, not bulky like tarantulas. Their coloration is typically a blend of grey, brown, and black, often with subtle banding on the legs.
What Happens If You Encounter a Huntsman?
If an accidental encounter with a Huntsman spider occurs, understanding their behavior is important. Huntsman spiders are non-aggressive and prefer to flee confrontation, using their speed to escape. As hunters, they play a beneficial role in controlling household pests like cockroaches. Bites are rare and typically only happen when the spider feels trapped or is defending its egg sac. The venom is not considered medically significant to healthy humans. A bite usually results in localized, temporary symptoms such as mild pain, swelling, and redness, which can be managed with basic first aid. Severe systemic reactions are uncommon.