Very few people welcome spiders into their homes. However, most spiders are not dangerous or venomous to humans. Of the 3,400 spider species found in North America, only two species pose any significant danger in the United States: the Brown Recluse and the Black Widow. Therefore, understanding how to identify the Brown Recluse and Black Widows as well as tell them apart from similar spiders is important in case of a spider bite. There are also two other varieties of spiders that are poisonous. They have a bite that can be painful, but not dangerous unless the person has an allergic reaction to the venom.
Most people see a small brown spider and immediately think "Brown Recluse." They are one of the most commonly misidentified spiders. Brown Recluse spiders live in the midwest, south and southwestern United States. They are often identified by a brown violin shape on their upper body. However, this shape is not always apparent. They also have six eyes arranged in pairs (most spiders have eight).
Close But No Recluse
Several species of spiders are often misidentified as Recluse spiders. The Spitting Spider is often mistaken for the Recluse because they are brown and have the same eye pattern; however, they have black stripes on their bodies. The Woodlouse Spider and southern House Spider are also similar to the Brown Recluse; however, their eyes are closer together and have no violin shape on their bodies. Finally, there are several species of spiders that have a violin shape including long-legged cellar spiders and pirate spiders. However, they have a mottled colour (not solid brown) and have eight, not six eyes.
When most people imagine a Black Widow, they think black spider with a red hour glass shape on the underside of its abdomen. Actually, Black Widows are not always black or have a red hour glass shape. They can also be dark brown to light brown or even grey and banded. The marking may be any colour from yellowish orange to red. The shape also varies from a round dot to the traditional hour glass and may even be absent.
Other Poisonous Spiders
Two other spiders that can be poisonous (but not deadly) live exclusively in the United States: the Grass Spider and the Hobo Spider. The Grass Spider is 3/4 inches long, brown to grey in colour with light and dark stripes near the head. The Hobo Spider is 1/2 to 2/3 inches long with legs 2/3 inches to 2 inches long, brown colour with chevron shaped markings on abdomen.
Orb Weavers come in all sorts of colours and shapes. They are identified by the large circular webs that are traditionally associated with spiders. Orb Weavers are not dangerous or poisonous, but can be a nuisance depending on where they make their webs.