Common Spiders of South Dakota: Identification and Safety Guide

South Dakota's prairies, badlands, and river valleys host diverse arachnid fauna. Most are harmless; a few warrant caution. Here are the species you're most likely to encounter.

1. American House Spider (Parasteatoda tepidariorum)

• Appearance: 4–6 mm, mottled brown/tan, bulbous abdomen.
• Habitat: Window corners, basements, garages.
• Risk: None. Non-aggressive; bite rare and mild.

2. Black Widow (Latrodectus hesperus, L. mactans)

• Appearance: Glossy black, 8–13 mm body; red/orange hourglass on ventral abdomen.
• Habitat: Woodpiles, sheds, meter boxes, rock walls.
• Risk: Neurotoxic venom. Bites painful; seek medical attention—rarely fatal to healthy adults.

3. Brown Recluse (Loxosceles reclusa) — Rare/Incidental

• Note: Not established in SD; occasional hitchhikers in shipped goods.
• Appearance: 6–20 mm, uniform tan, violin-shaped dorsal marking.
• Risk: Necrotic venom. If bitten, seek care immediately.

4. Grass Spiders / Funnel Weavers (Agelenopsis spp.)

• Appearance: 10–20 mm, brown with longitudinal stripes; fast runners.
• Habitat: Lawns, fields, low shrubs—sheet webs with funnel retreat.
• Risk: None. Shy; bite only if trapped.

5. Jumping Spiders (Salticidae — multiple genera)

• Appearance: Compact, 4–15 mm, large anterior median eyes, often iridescent chelicerae.
• Habitat: Walls, fences, plants—active daytime hunters.
• Risk: None. Curious, often approach humans; bite harmless.

When to Call a Pro

• Suspected brown recluse (verify with extension office).
• Multiple black widows in high-traffic areas.
• Unexplained necrotic wound.

Most South Dakota spiders are beneficial pest controllers. Learn to recognize the widow's hourglass, and coexist peacefully with the rest.