On one hand, all spiders are venomous. They need venom to subdue and digest their prey. On the other hand, most North American spiders are harmless to people. The two exceptions are the black widow and the brown recluse, but these two have many fairly harmless imitators. If you want to know the difference, read on to learn what to look for.
The Black Widow
This infamous spider is easy to tell apart from just about every other kind. Like all spiders, she has eight legs, but she also has a round abdomen, patent leather black save, and the tell-tale red hourglass on her abdomen. However, only the female black widow is dangerous. The much smaller male is harmless and more timid than the female. And he has every reason to be: During courtship he’s at risk of being eaten by the female. This is why the spider is known as a widow.
Besides the black widow, there’s the brown widow and the red widow. The brown widow can also be black, but is often brown or gray. She is less likely to bite than the black widow and injects less venom. The red widow has red splotches on the top of her abdomen, as well as the tell-tale hourglass. Another variety of widow is also black, but the hourglass on her abdomen is broken in two. Yet another, the Malmignatte, is black with red streaks on her abdomen, and is found in Mediterranean countries. Widows are found in the warmer places in the world, often around human habitation.
There are several species of spiders that people may mistake for widows. They include the Steatoda, Theridion and Enoplognatha spiders and Dipoena nigra. The females of these spiders all share the round abdomen of the black widow, but lack her red hourglass. They are also far less dangerous.
The Brown Recluse
The brown recluse is known for resting with its legs in a crab-like position. It also has a distinctive fiddle-shaped mark on the top of its thorax, which gives it the name the fiddle-back spider. Because of its coloration and the way it holds its legs, the brown recluse might be mistaken for spiders of the Thanatus and Philodromus genera. These are crab spiders that are mostly found in bark and around plants, though Philodromus spiders have been known to come into the house.
Poisonous Spider Bites
Poison from both of these spiders can cause various symptoms that vary with age. Younger kids are at much more risk than adults. Bite areas will usually swell, becoming irritated and red. A victim might show other signs like fever, shivering, nausea and vomiting. Call poison control or 911 right away if bitten.
Most spiders are docile and are helpful in getting rid of other household pests, but if you really can't bear them, get in touch with a local pest control company. Professionals can assist in determining if the spiders around your house really are dangerous and can help to keep them from coming inside.
Brooke Chaplan is a freelance writer and blogger. She lives and works out of her home in Los Lunas, New Mexico. She loves the outdoors and spends most her time hiking, biking and gardening. For more information contact Brooke via Twitter, @BrookeChaplan.