In El Dorado County, spiders are a common occurrence. Although they are more plentiful in the late summer and early fall, they can also be a problem in winter. During the cold winter months, spiders will huddle up next to a house for warmth and protection from the weather. They prefer to live outside but occasionally will come inside.


One way spiders enter a house is through the transportation of firewood. Spiders love to nest in your woodpile. It provides lots of shelter and each piece of wood can have numerous hiding places. When it‘s cold, spiders may not be very active and thus, hard to spot. But when that piece of wood is brought inside and set next to the fireplace, it warms up and the spider will emerge. We recommend that you put gloves on and inspect each piece of firewood for the presence of spiders before bringing it into the house.


Spiders are not insects, although they are Arthropods. Spiders have two body segments (cephalothorax and abdomen), eight legs and six or eight eyes. Insects have three body segments (head, thorax, and abdomen), six legs and two compound eyes.


Two of the most common spiders in El Dorado County are the Wolf spider and Black Widow spider. Wolf spiders are normally dark brown and have a hairy, stout body. They look intimidating, have rapid movements, and can run quickly. They are not associated with webs but will leave draglines or safety lines. The female wolf spider carries an egg sac on her rear. When the spiderlings hatch, they climb on their mothers back and ride around before gradually dispersing. Wolf spiders have strong, piercing mouthparts that will inject venom, but their bite is less painful than a bee sting. Wolf spiders are not poisonous to people, although their bites may cause a reaction in certain individuals.


The black widow is another spider that is common to our area and is easily identified. The females are glossy black and have a red hourglass marking on the underside of the abdomen. They are very shy and will usually retreat to a corner of their web when disturbed. However, they will be more aggressive if they are protecting an egg sac.

Their webs are irregularly shaped, sticky and extremely strong. When bitten, a neurotoxin is released that causes dull pain and cramping in muscles, which can be accompanied by sweating and vomiting. Fortunately, less than 1% of black widow bites are fatal.

First aid for a black widow bite can include the following: use an ice pack or alcohol to reduce swelling in affected area; clean the area with hydrogen peroxide or alcohol to minimize infection; attempt to collect the spider for proper identification; and seek medical attention at an emergency room.