Scorpions are often associated with arid, desert environments, but their range extends surprisingly far into temperate regions. For those in the Great Lakes region, particularly Michigan, the possibility of encountering a scorpion sparks curiosity. The search for a definitive answer about a “state’s only scorpion” requires looking at established geographic boundaries and the ways they can accidentally travel.
The Reality of Native Scorpions in Michigan
Michigan does not have any established, naturally occurring species of scorpion. The cold winters of the upper Midwest are generally too harsh to support long-term breeding populations. The natural northern boundary for established populations in the central United States reaches states like Nebraska, South Dakota, and North Dakota.
The northernmost species, the Northern Scorpion (Paruroctonus boreus), extends into these states and Canada, but its established habitat does not include Michigan. While this species tolerates cold, the Great Lakes climate is outside the ecological niche required for a self-sustaining population. Therefore, any sighting of a true scorpion in Michigan represents an accidental import.
The confusion often stems from the presence of pseudoscorpions, which are common across Michigan. These minute arachnids resemble scorpions, possessing large pincers but lacking the characteristic tail and stinger. Pseudoscorpions are harmless to humans and are often found indoors, where they prey on small pests like booklice and mites.
Accidental Sightings and Identification
Scorpions found in Michigan are nearly always unintentional stowaways, typically transported in landscaping materials, cargo shipments, or luggage from warmer climates. The two species most likely to be accidentally transported are the Striped Bark Scorpion (Centruroides vittatus) and, less frequently, the Northern Scorpion. The Striped Bark Scorpion is common throughout the South and Midwest, making it a frequent accidental traveler.
Accurate identification is important due to varying levels of venom toxicity among species. The Striped Bark Scorpion is medium-sized, reaching about 70 millimeters in length, and is characterized by two dark, longitudinal stripes running down its pale-yellow body. In contrast, the Northern Scorpion (Paruroctonus boreus) is typically a light brown or olive color and measures between 35 to 55 millimeters.
A general rule for North American species involves examining the pedipalps, or pincers, in relation to the tail. Scorpions with thick, robust pincers often have milder venom, relying more on crushing prey. Conversely, species with slender pincers tend to have more potent venom. The presence of a scorpion that fluoresces a vibrant blue-green under ultraviolet light can also confirm the sighting, as this is a common trait.
Risk Assessment and Safety Protocols
The risk posed by an accidental scorpion sighting in Michigan is low. The few species transported typically have venom that is not life-threatening to healthy adults. For example, the venom of the Northern Scorpion is generally mild, causing localized pain and swelling similar to a bee sting. However, any sting warrants attention, particularly for children, the elderly, or individuals with known insect venom allergies.
If a scorpion is encountered, the most important safety protocol is to avoid direct contact and not attempt to handle the arachnid. Scorpions sting defensively, often when they feel trapped or accidentally disturbed. Stings from the Striped Bark Scorpion, while usually not severe, can cause symptoms beyond local pain, such as numbness, tingling, or muscle twitching.
Medical attention should be sought immediately if a sting is followed by systemic symptoms, including difficulty breathing, widespread swelling, or signs of a severe allergic reaction. Reporting the find to a local university entomology department or the Department of Natural Resources (DNR) can help track unusual occurrences. This provides valuable data and helps experts understand the routes of accidental introduction.