Spider identification made easy starts with the types of spiders that people normally come across in daily life. They are often found in home, garden and lawns across North America.
Formally spider types get arranged according to families. Less formally, spider types are often categorized according to their hunting methods. Some spiders use webs to trap prey. Some spiders hunt prey in their territory. Both formal and informal ways of thinking about spiders help with spider identification.
Press any button to learn about some of the spiders discussed in the article. Or continue reading below.
Common House Spiders
The spider pictures presented in this section use both methods, and it starts with an always hot topic, common house spiders.
Using the widest of definitions, all types of spiders found within a residential dwelling might rightly be placed in the house spiders category.
In fact, most people’s squeamishness around spiders often translates into dramatic interpretations regarding their presence. To this population, it almost goes without saying that any spider found in the house is naturally a giant, gigantic, large and hairy, scary spider, or something close to that description.
True enough. One spider species, Eratigena atrica, a member of the funnel weaving family pictured at the top of the page, also formally goes by the name Giant House Spider because it can grow up to four inches from leg to leg. Its close relative, Eratigena agrestis goes by the name Hobo Spider, with unconfirmed reports of its being a spider of medical importance.
Sometimes house spiders can be a tad bit big and scary.
Depending on geographic location, the presence of house spiders can also be meddlesome. Some areas such as the Southeast and Northwest tend to attract more spiders into homes because of the presence of larger native spider populations. Houses with overgrown vegetation against the exterior also tend to attract greater numbers of spiders.
Considering all the types of spiders that live in residential areas, it’s a safe bet that all houses occasionally host at least one spider.
Cellar Spiders rightly belong in the common house spiders category. Their long legs makes the nick-name daddy long legs appropriate. However, their two body parts puts them in the spider category rather than the Opilione category of another daddy long legs species. The picture shows a close-up view of the cellar spider’s two body parts.
While cellar spiders might be considered an eyesore, they are harmless.
Types of Spiders: Cobweb Spiders
With close to two hundred and fifty species covering over thirty genera, there’s a good chance that a cobweb spider (family Theridiidae) makes its way into the average household. Of course the real problem with cobweb spiders boils down to a few species in one genera, widow spiders in the genus Latrodectus.
Apart from the widow spiders, which fortunately prefer outdoor settings near woodpiles in residential areas, the presence of cobweb spiders in the house presents little cause for concern.
Initial identification of the cobweb spiders is rather straight forward. Most have extra large front legs. Their abdomens tend to be more rounded in shape. The picture shows the triangulate cobweb spider (Steatoda triangulosa) probably the most wide ranging of the species and the most common cobweb spider found in homes and sheds across the United States.
Often the Steatoda species acquire the nickname false widow. The name false widow comes from the spider’s looks. From a distance, the body often appears dark, like the black widow spider. The picture shows a less common species, Steatoda Grossa. With the legs extended, it measures approximately and inch and one-quarter in length.
Their bites are known to cause pain and discomfort for a small portion of the population, however for most people, their bite produces no side effects.
Less well known is the fact that many cobweb spiders, including widow spiders, also find a home in the great outdoors.
The picture shows Enoplongnatha ovata. Note how the first set of legs are the longest. That’s another physical characteristic shared by members of the family.
Funnel Web Spiders
Often called grass spiders, the funnel web spiders (Agelenidae) also occasionally wander into houses during cool weather. Looking at their tail end represents one general funnel web identification rule of thumb. Many species have extended spinnerets and this differentiates them from wolf spiders.
A close up picture of the eyes also helps with identification. Funnel web spider eyes are arranged in two narrow and relatively straight rows. The eye arrangement gives them a forward looking appearance.
Most funnel web spiders are not considered dangerous to humans. The Hobo Spider in the Pacific Northwest would be the exception.
Other House Spiders
For homeowners whose houses are build on the ground (probably most homeowners), sometime or another a ground spider (family Gnaphosidae) will wander onto a window sill or wall. Many ground spiders are small and resemble ants like the one in the picture. They present no harm to anyone in the house.
West Coast residents can often find a Mouse Spider (Scotophaeus blackwalli) crawling on a wall. They are a bit larger than the more wide ranging ground spider species, and they are also European imports that found their niche in West Coast homes.
There’s a Spider in My Bathtub
How many times have you heard, said or thought the question, “there’s a spider the size of a tennis ball in my bathtub, what should I do”? There are two answers to the question.
First, you can take comfort in knowing that the question is commonly heard in households with bathtubs around the world. Spiders and bathtubs go together like peanut butter and jelly. The reasoning is simple. During the mating season wandering male spiders travel around the house. They accidentally fall into the bathtub and are unable to escape because of the tub’s slippery sides.
Given the configuration of most modern plumbing systems, it is highly unlikely that the spider crawled up through the drain.
The second suggestion would be to check your math. It is not uncommon for people to exaggerate the size of a spider on first sight. If the spider in the tub is really the size of a tennis ball, there is good news. Your spider is most likely not the more dangerous hobo or recluse spider. It is probably a giant house spider on the West Coast or a Hunstman’s spider in the Southeast.
The third course of action is optional, depending on the number and squeamishness levels of the household members. The least squeamish member can trap the spider under a glass, slide a sturdy piece of cardboard beneath the opening, and carry and release the spider in the outdoors.
Please remember to release the spider some distance from your house, or chances are he will soon visit again. House spiders rank among the speediest spiders on earth and yours may very well race you back home.
All spider webs are made from silk, produced by an organ called spinnerets, which are located on the spider’s abdomen.
All spiders, including the hunting spiders, use silk for one reason or another. Jumping spiders, for example, although formally classified as hunting spiders, use silk as a type of bungee cord for added protection as they literally jump from leaf to leaf or branch to branch in search of prey.
Because of their specialized hunting method, web building spiders typically have a larger number of silk glands than hunting spiders.
Spiders are often further classified according to the types of webs they build. Three of the better known groups of spiders that build different types of webs are the orb weavers, cobweb spiders and funnel weavers. Many common garden spiders, such as the writing spider, are orb weavers.
, Long-jawed Orb Weavers have the name orb weaver, however they belong to a different family (Tetragnathidae) than the spiders in the Araneidae family.
The obvious question to ask is if they build orb webs, why are they not in the orb weaver family? Good question. Members of the family share a similar physical characteristic of an overly large jaw compared to thee other orb weavers.
The picture also shows another dominant physical characteristic of the family. They have elongated abdomens and legs. They can often be found sunning on a leave with their legs extended.
Their are nine genera in the family. All but three of the genera have two or less species. Those species have a limited range.
The genus Tetragnatha basically represents most of the family on a coast to coast basis.
In the east, two members of the Leucauge genus, Orchard spiders are recognized. Here’s an Orchard Spider, another member of the Long-jawed Orbweavers.
Hunting spiders is the catch all term for all types of spiders that do not spin webs to catch prey. Wolf spiders, jumping spiders and crab spiders might be the most common hunting spiders found around the neighborhood.
Often the jumping spiders and crab spiders hang out on flowers and plants seeking an unsuspecting insect to stop by. As a matter of fact, for all most spiders, including the hunting spiders, have eight eyes, each arranged differently around the head.
The eye arrangement of the spider in the picture indicates it is a wolf spider.
Jumping spiders are the largest spider family in terms of species, therefore it stands to reason that a good chunk of the population can often find multiple species in their yard.
Consider, for example, on genus of jumping spiders. Well over two dozen North American Phidippus jumping spiders inhabit the brush and walls around residential areas.
Differences among Phidippus deal more with color than with body form. Generally, Phidippus species have darker banded legs, with shades of black, brown, red or yellow on the cephalothorax and abdomen.
The majority of Lynx Spiders (family Oxyopidae) live in tropical and subtropical areas of the world.
However, species in three different genera can be found in the United States.
The are small to medium sized hunting spiders, and like the crab spiders and jumping spiders, their preferred habitat consists of low growing plants and bushes.
Tarantulas are timid spiders that inhabit southern areas, especially the Southwest. They are also one of the types of spiders that gets grouped with Mygalomorph spiders.
Species names such as purseweb spiders and trapdoor spiders explain the activities for most Mygalomorph species. They dig burrows filled with silk and then extend the silk outward in some manner to trap their prey.
Yellow Sac Spiders (Cheiracanthium) commonly inhabit residential areas and can wind up on walls. While they are not considered spiders of medical importance (more commonly known as poisonous), their bite can be painful.
What Do Spiders Eat?
Spiders, long considered carnivores, (although there might be exceptions to that rule), traditionally choose insects and other arachnids as their primary source of food.
Arachnologists, scientists who study spiders, have long been intrigued by spider diets. One question they consider, “Are Spiders Picky Eaters”, has been the subject of both observation and scientific experimentation.
A pair of arachnologists conducting experiments on the pickiness of spider eating habits, started with the hypothesis that spiders eat any insects that come their way.
They conducted an experiment with an Araneidae species, an orb weaving spider (Micrathena Gracilis).
Over an extended period of time, they counted the number and size of insects that flew into the web. They also recorded the number and size of the insects that the spider captured for dinner.
Testing the null hypothesis meant that the researchers thought that the spider would eat all the insects that landed in the web, regardless of insect size.
At the end of their experiment, they concluded that when given the choice between large and small insects caught in the web, the spider preferred larger insects.
In scientific terms, they concluded there was a statistically significant relationship between spider diet and insect size. The hypothesis that spiders are picky eaters still stands.