How to Identify Spiders

Three Parts:Looking at Identifying Features and HabitsRecognizing Venomous SpidersConducting Further Research

There are over 44,000 spider species the world over, and the only way to truly identify one is to have an expert examine its anatomy under a microscope. However, familiarizing yourself with spiders' defining characteristics can help you take a good guess as to what spiders you might encounter where you live. To learn what to look for and how to tell if that giant, hairy spider in your bathroom is dangerous or harmless, see Step 1.

Part 1
Looking at Identifying Features and Habits

  1. 1
    Make sure it's really a spider. A lot of people think spiders are insects, but they're actually very different. To determine whether the creature you've encountered is really a spider, look for the following qualities:
    • 2 body segments. Unlike insects, which have 3 body segments, spiders only have 2.
    • 8 legs. Don't mistake an insect's antennae for legs.
    • No wings. No species of spider has wings, so matter how spider-like the creature may otherwise appear, if it has wings, it's not a spider.
  2. 2
    Examine the eyes. Spiders' eye number and location on the body varies widely among different species.[1] If you can, get close enough to look at the spider's eye size, count and arrangement. This will help you narrow down which family the spider is in.
    • Spiders might have 4, 6, or 8 eyes arranged in different patterns.
    • Try to take a picture of the spider, then zoom in to see the eye count and pattern.
  3. 3
    Notice the spider's coloring. This is another important way to figure out what type of spider you're seeing. Take note of the spider's primary color - usually a shade of brown, black or grey - and notice variations, subtle or not so subtle, that will give you a clue as to what type of spider you're looking at.
    • Does the spider have spots, or a striking shape - such as the brown recluse's classic violin shape?
    • Are the legs the same color as the body?
    • Note that many species of spider have similar coloring, so looking at this characteristic alone won't be enough to give you a definitive answer.
  4. 4
    Look at the shape of the legs. Once you've counted the legs, examine them more closely. Look at the size of the legs in proportion to the body. Some spiders have long, thin legs, while others have stocky, thick legs. Some spider have tiny hairs on their legs, while others have spikes or fur.
  5. 5
    Look at the spider's habitat. The place where you encountered the spider, as well as the web or burrow in which you found it, are also important factors. Answer the following questions regarding the spiders habits:
    • Where did you find the spider? Was it in the bathroom, the basement, the shed, outside? Was it in a dark place, or a place with plenty of light? A wet place or a dry place?
    • What type of web does the spider have? Is it a classic-looking spider web, a tunnel web, or just a few strands of webbing that aren't neatly woven?
  6. 6
    Assess the spider's behavior. Some spiders are aggressive, and will start moving toward you when they notice your presence. Others hide, and still others stay put instead of moving. Pay attention to any other behaviors you notice that could help you figure out what type of spider it is.[2]

Part 2
Recognizing Venomous Spiders

  1. 1
    Determine if you've got a brown recluse on your hands. When it comes to spider identification, the first one you'll want to rule out (if you live in North America) is the brown recluse. This is the most dangerous spider in the US, and is found most often in the Southeast and Midwest.[3] A brown recluse bite can cause infection, and medical attention is usually necessary. Here's how to know if the spider is a recluse:
    • Look for the tell-tale violin shape on its back. The brown recluse has a medium brown body and legs, with a slightly darker brown violin shape on the back.
    • Count the eyes; if there are 6, it might be a recluse. The recluse's eyes are arranged in pairs, with one pair in front and a pair on either side.[4]
    • Analyze where you found the spider; if it's in a warm, dry place, like a shed or woodpile, it might be a recluse.
    • The brown recluse is known to be aggressive, rather than hanging back when it encounters someone.
  2. 2
    See if it's a black widow. Black widows are common in the Southern and Western states in the US. When they bite, they release a neurotoxin that causes pain and other severe effects, especially in children and the elderly.[5] Here's what to look for:
    • These aptly-named spiders are a striking shiny black color, with a bright red hourglass shape on the abdomen.
    • Black widows commonly dwell in woodpiles and under eaves.
    • They have long legs that taper into points.
  3. 3
    Find out if it's a hobo spider. This is the third commonly seen venomous spider in the US. It's commonly seen in the Pacific Northwest. Its bite is not quite as dangerous as that of a brown recluse or black widow, but medical attention is still necessary when a bite occurs.
    • Hobo spiders are brown with chevron-shaped yellow markings.[6]
    • They make their webs in cracks, corners and holes, and can be found in woodpiles and other sheltered places.
  4. 4
    Know which spiders aren't dangerous. All spiders have a small amount of venom, but many spiders that look decidedly creepy won't actually cause a dangerous reaction when they bite. If the spider you see can't clearly be identified as a brown recluse, black widow, or hobo spider, it probably won't cause you any harm. In fact, having some spiders around is beneficial to the environment; they keep insect populations down so you don't have to use pesticides.

Part 3
Conducting Further Research

  1. 1
    Know what species are common in your region. If you live in New York, you probably aren't going to encounter the fearsome banana spider (although it's certainly not impossible). Getting familiar with the species that live in your area is a good way to narrow down the possibilities when it comes to identifying spiders.
    • There are many excellent resources you can use to learn more about spiders. Check out a book from your library or look at spider databases online. You can search according to region.
  2. 2
    Take a picture of the spider if you can. If you're bent on figuring out exactly what species of spider you've spotted, get up close and take a picture. If possible, try to capture a picture of the spider's underside as well as the top. Since so many spiders look alike, it's impossible to know for sure what you're seeing until you compare the spider's image to that of other spiders that have been definitively classified by scientists.
  3. 3
    Do research to figure out what species it is. Now that you've taken note of the spider's appearance and habits, and you have a picture to back yourself up, you can use the World Spider Catalog[7], the online Journal of Arachnology[8], and other resources put together by experts to look up the spider and compare it to pictures of different species. Here are a few of the amazing arachnids you might encounter:


  • Don’t forget to destroy a spider’s egg sacs when you are trying to rid your home of spiders.
  • Before going on a vacation, it’s a good idea to familiarize yourself with spiders native to the country or region you plan to visit. Field guides are available at your local book store or library.


  • All types of spiders are important to the eco-system. They are predators and control the pest population in vegetable gardens and fruit orchards. If at all possible, avoid killing spiders; most are not harmful or poisonous to humans.
  • Seek medical attention if you are bitten by a poisonous spider, or if you are allergic to spider bites.

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Categories: Spiders and Other Arachnids