What Do False Widow Spiders Look Like? Identification Guide

False widow spiders have become a topic of growing interest and concern in recent years due to their often-misunderstood nature and the fear they evoke. While they are sometimes mistaken for the infamous black widow spiders, false widows are generally less dangerous but still deserve respect and caution. Knowing how to identify these spiders helps reduce unnecessary panic and promotes safe coexistence.

In this comprehensive identification guide, we will explore the physical characteristics, behavior, habitat, and common species of false widow spiders to help you recognize them confidently.

Understanding False Widow Spiders

False widow spiders belong to the genus Steatoda, which is part of the Theridiidae family—commonly known as comb-footed or cobweb spiders. There are over 30 species worldwide, but the most commonly encountered false widows in Europe and North America are Steatoda nobilis and Steatoda grossa.

Despite their intimidating name, false widows are not closely related to true widow spiders (genus Latrodectus), which include the dangerous black widow. False widows tend to have less potent venom and rarely cause serious harm to humans.

General Physical Characteristics

Size

• Body length: Adult false widows typically range from 6mm to 14mm in length, with females larger than males.
• Leg span: Their legs can extend up to 20mm or more, making them appear slightly bigger.
• Sexual dimorphism: Females tend to have a more robust abdomen while males are slimmer with longer legs relative to body size.

Body Shape

False widow spiders have a rounded, bulbous abdomen that is usually shiny or glossy in appearance. Their body shape resembles that of true widows but without the distinctive red hourglass marking on the underside.

The cephalothorax (the front combined head and thorax segment) is smaller compared to the abdomen and often darker or more matte in color.

Coloration and Markings

One of the key ways to identify a false widow spider is through its coloration:

• General color: The body ranges from dark brown, reddish-brown, or purplish-brown.
• Abdomen: Most false widows have creamy white or pale markings on their abdomen, often forming a pattern resembling a skull or a series of spots and streaks.
• Glossy finish: The abdomen often has a shiny or satiny surface which makes these patterns stand out.
• Legs: Legs are usually dark brown or blackish with lighter bands or spots near the joints.

The color patterns can vary significantly between species and individuals due to age and environment.

Key Species of False Widow Spiders

Steatoda nobilis (Noble False Widow)

• Description: The most notorious false widow species, native to the Canary Islands but now widespread in Western Europe including the UK.
• Appearance: Dark brown or purplish-black with ivory or cream-colored markings on the upper surface of its abdomen. These markings can look like a skull or abstract blotches.
• Size: Females grow up to 14mm; males slightly smaller.
• Behavior: Builds tangled cobwebs in sheltered places like sheds, garages, window frames, and garden furniture.

Steatoda grossa (Cupboard Spider)

• Description: Commonly found indoors in homes worldwide.
• Appearance: Usually darker overall with less distinct cream markings. The abdomen is glossy and round but tends to be darker with subtle patterns.
• Size: Similar size to S. nobilis, around 10-14mm for females.
• Habitat: Prefers indoors – cupboards, basements, corners of rooms.

Steatoda triangulosa (Triangulate Cobweb Spider)

• Description: Smaller and less intimidating than other false widows; has distinct triangular markings on its abdomen.
• Appearance: Light brown with three dark triangular spots forming a pattern along the abdomen’s dorsal side.
• Size: Smaller at 4–6mm body length.

Distinguishing False Widows From True Widows

Many people confuse false widows with true black widows because both feature bulbous abdomens and dark coloration. Here are some tips to tell them apart:

| Feature | False Widow (Steatoda) | True Widow (Latrodectus) |
|———————-|—————————————————-|————————————————|
| Abdomen Color | Brownish to purplish with pale patterns | Shiny black |
| Abdominal Markings | Creamy white/yellow blotches or skull-like patterns | Distinct red hourglass shape on underside |
| Size | Females up to 14mm | Females larger – up to 15mm+ |
| Web Type | Tangled cobwebs | Irregular webs but often less dense |
| Bite Severity | Mild venom; bites rarely dangerous | Neurotoxic venom; bites medically significant |

Behavior and Habitat

False widow spiders are primarily nocturnal hunters that build messy cobwebs in quiet, sheltered areas where prey such as flies, ants, beetles, and other small insects get caught.

Common habitats include:

• Gardens underneath logs or stones
• Around homes — window frames, eaves, sheds, garages
• Indoor spaces — cupboards, basements
• Dark corners inside buildings

They are shy and avoid human contact but will bite if provoked or trapped against skin.

How To Identify A False Widow Spider In Your Home

If you suspect a spider is a false widow in your home or garden:

1. Examine its size and shape: Is it about 1cm+ with a round glossy abdomen?
2. Look for distinctive markings: Creamy white blotches on dark brown/purplish background?
3. Check web location: Is it found in tidy cobweb clusters in corners or crevices?
4. Compare with images: Use reliable online resources or spider identification guides focusing on Steatoda species.
5. Avoid handling: If unsure about identification, avoid touching the spider directly.

Are False Widow Spider Bites Dangerous?

While false widows are venomous—as most spiders are—their bites usually cause only mild symptoms such as localized pain, redness, swelling, or itching. Serious medical issues after bites are extremely rare.

Symptoms may last a few days but typically resolve without treatment. People who experience severe allergic reactions should seek medical attention immediately.

Preventing Encounters With False Widows

To minimize unwanted encounters:

• Keep outdoor clutter like woodpiles away from your house.
• Seal cracks around windows and doors where spiders might enter.
• Regularly clean corners where webs may form inside your home.
• Use yellow outdoor lighting that attracts fewer insects which reduces spider prey availability.

Conclusion

False widow spiders may look intimidating due to their bulbous abdomens and striking markings but they are generally harmless creatures that play an important role controlling insect populations. Knowing what false widow spiders look like—from their size and shape to their coloration—helps dispel myths and reduces fear. They differ significantly from true widows in appearance and danger level.

If you find one in your home or garden, remember they prefer avoiding humans but can bite defensively. Respecting their space while practicing simple prevention measures keeps both you and these beneficial arachnids safe.

By learning how to identify false widow spiders correctly through this guide, you empower yourself with knowledge that enhances safety without fear.