Black widow spiders are very venomous and can cause extreme pain or sickness if you are bitten by one. These spiders live throughout the United States and typically in warmer regions of the world. With the possibility of encountering such a dangerous species, it’s useful to know how to identify them. While the adult females are the only ones with large enough fangs to bite humans, seeing young or male black widows will typically indicate a female black widow is nearby.
In addition to knowing what black widows look like, it is also important to identify other spiders that look like black widows. For example, most spiders in the Genus Steatoda are known as “false black widow spiders” because of their similarity in appearance. Understanding the difference between these spider species can help you take appropriate actions, especially if you are bitten.
This article will cover how to identify black widows and more information on 8 species that look similar to them.
8 Spiders That Look Like Black Widows
While black widows are venomous with painful bites, not all the spiders on this list that look like them are harmful to humans. Let’s learn more about the spiders living in Northern America that look like black widows.
1. Cupboard Spider
Scientific name: Steatoda grossa
The Cupboard spider is from the same family Theridiidae as the black widow spiders and is known as one of the false widow species. They build similar irregular webs and females are most commonly mistaken for black widows. Female cupboard spiders have similar large body shapes and are typically black. However, they aren’t as glossy as black widows and don’t have the red hourglass marks on their abdomen. Sometimes these spiders are also more of a dark purple.
Female Cupboard spiders are typically 0.25 to 0.4 inches in body size and males are smaller. Males also have an elongated abdomen and are often lighter in color. These spiders only bite if they feel trapped or attacked, so never touch their cobwebs with your hands. Their bites are not as severe as the black widow but can be painful and lead to blisters around the bite area.
Although more common in California and the east coast, Cupboard spiders have spread throughout the U.S. You can now find them in every state, including Alaska and Hawaii.
2. Noble False Widow
Scientific name: Steatoda nobilis
Although the Noble false widow spider is more common in the U.K. than in the U.S., you can find this species in California. It is the largest of the false widow species, typically growing between 0.33 to 0.43 inches. Some females can grow up to 0.53 inches.
The Noble false widow has irregular, messy webs similar to black widows. They also have large bulbous abdomens. However, their coloring is more brown than black and typically has cream markings without red spots or an hourglass pattern.
These spiders have venomous bites, but they are not as severe as the black widow. The pain is similar to a wasp sting and usually lasts between 1 to 12 hours. However, you should make sure to keep the wound clean to prevent any bacterial infection.
3. Rabbit Hutch Spider
Scientific name: Steatoda bipunctata
The Rabbit hutch spider is the third species of false widow spider. However, their bite is not harmful to humans. They rarely bite humans, so there is little information available regarding the severity of their bites. Some reports have people equating it to a bee sting.
These spiders are the smallest of the false widows, with females growing to around 0.3 inches. Their body shape is similar to black widows and they are sometimes black but lack the red hourglass marking. They can also be brown with a light, thin stripe curved along the middle of their abdomen.
You can find these spiders throughout the U.S., including in Alaska and Hawaii. As their name suggests, they often make a home in rabbit hutches. However, you can also find them in dry rooms, gardens, bushes, wall crevices, and under stones.
4. Triangulate Cobweb Spider
Scientific name: Steatoda Triangulosa
The Triangulate cobweb spider gets its name from the triangulate mark on its abdomen. This mark combined with its brownish-black color can make it easily mistaken for a black widow, especially a male or young female.
You can find these spiders throughout North America. Oftentimes they hang out in dark corners of your house on irregular webs, including in basements, outbuildings, and garages. They grow around 0.25 inches in body size. Their bite is also not harmless to humans, with rare reportings of people being bitten by them.
5. Barn Funnel Weaver
Scientific name: Tegenaria domestica
The Barn funnel weaver is found in 19 states in the U.S., including Colorado, New York, Hawaii, Utah, Washington, and Missouri. They also exist in Europe, where they are commonly referred to as the Domestic house spider. Although not black like the female black widow, their typical brown and tan coloring and markings make them look similar to male and young female black widows.
These spiders rarely bite humans and are not venomous to us. However, a bite from a barn funnel weaver might cause redness, swelling, or some itching. Female Barn funnel weavers are larger than males, growing around 0.3 to 0.45 inches in length. Males will grow between 0.24 and 0.35 inches in length.
6. Red-Spotted Ant Mimic Spider
Scientific name: Castianeira Descripta
The Red-spotted ant mimic spider is easily mistaken with the black widow because they are black, hairless, and have red markings on their abdomen. However, these spiders have the mark on the top, and it’s typically a thick curved band down the middle with a white line. Unlike the black widow, their bite is not harmless to humans and more similar to a bee sting.
This spider is a hunting spider. Meaning it doesn’t build webs to catch prey, but instead wanders around for prey. They prefer ants and get their name from the behavior they do to mimic ants. They will walk on their back six legs and raise their front pair like antennae, so ants and insects think they aren’t dangerous.
You can find them throughout North America, near woods, shrubs, stones, and parks. They are around 0.5 inches long, with females larger than males.
7. Brown Widow
Scientific name: Latrodectus geometricus
Although still a venomous widow spider species, the Brown widow bite is less painful than black widows. It can be easy to confuse the two species when they are young since they look very similar. Adult female Brown widow spiders are dark brown and tan with a reddish hourglass mark that is duller compared to the bright red mark of the black widow.
This spider also looks similar to the triangulate cobweb spider, which is significantly less venomous. One way to identify the brown widow is by looking at their egg sac. The Brown widow’s egg sacs are tufted or spikey.
You can find these spiders in California, Hawaii, and warm southern states from Florida to South Carolina. Females grow around 0.5 inches in body size and have a leg span of up to 2 inches long. Males are typically smaller.
8. Red Widow
Scientific name: Latrodectus bishop
Although the adult female Red widow spider has the same large, rounded black abdomen with red markings as the black widow, these spiders are not black widows. Their legs are typically reddish or orange and their underbellies don’t have a complete hourglass. Instead, they have red triangular-looking marks. Females can grow around 0.5 inches in body size, with males much smaller.
You can typically find these spiders in southern and central Florida. They prefer dry sand dunes and sand pines, so they generally don’t interact with humans. Although highly venomous, there are limited reports of people being bitten by them. Their venom also contains a neurotoxin that causes muscle spasms.
How to Identify Black Widows
Before looking at spiders similar to black widows, let’s explore the key ways to identify the black widow. The three main species of true black widows found throughout the United States are:
- Northern black widow (Latrodectus variolus)
- Southern black widow (Latrodectus mactans)
- Western black widow (Latrodectus Hesperus)
Color and Markings
Females are shiny black and have a characteristic bright red hourglass mark on the bottom of their abdomens. This mark looks like two triangles that connect or are separated by a black stripe. They can also have 4 red or yellowish-orange spots on top of their abdomen.
Males and young black widows are typically white and tan, with reddish-brown legs. They may have patterns, such as stripes, on their abdomen or red dots.
Most black widows grow around 0.25 inches long. However, females are typically bigger, growing up to 0.5 inches long, excluding their legs. The female’s abdomen is large and round like a blown-up ball. In contrast, the male abdomen doesn’t enlarge as much and is slightly more elongated.
A black widow spider will have irregular, messy webs near ground level. They usually spin their webs under ledges such as woodpiles or lawn furniture. These spiders will also spin spherical egg sacs.