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10 Common Spiders in Idaho (Pictures)

When you think of Idaho, the first thing that comes to mind might be potatoes, but that’s not the only thing Idaho has to offer. The state is home to several common species of spiders as well. Luckily, most spiders in Idaho are harmless and help control the insect population. The following list will show you a few of the most common spiders in Idaho.

10 Common Spiders in Idaho

Starting with the venomous and infamous black widow, the following list of Idaho spiders can be found in various parts of the state and in various habitats. Some even make their way into your home!

1. Western Black Widow

Western black widow
Male Western Black Widow | image by Alan Moore via Flickr | CC BY-ND 2.0

Scientific Name: Latrodectus hesperus

The Western black widow is native to the western part of the United States and can be found in Idaho. The venomous females have a glossy black body, bulbous abdomen, and a red hourglass-shaped mark on their underbelly.

The males are brown or gray and have a small red dot on their abdomen instead of an hourglass-shaped mark. The females can grow up to half an inch in length, and the males only grow to be about one-third that size.

2. Banded Garden Spider

Banded garden spider
Banded garden spider | by USFWS Mountain-Prairie via Flickr

Scientific Name: Argiope trifasciata

The banded garden spider is one of the most common types of orb-weaving spiders in Idaho. Orb weaving spiders build orb-shaped webs, and the banded garden spider creates webs around two feet in diameter.

Including their legs, these spiders can grow up to three inches in length. Their abdomens are white with black and yellow bands, and their legs are red with black bands. These bands are where the spiders get their name.

3. Hobo Spider

Hobo spider
Hobo spider | image by Géry Parent via Flickr | CC BY-ND 2.0

Scientific Name: Eratigena agrestis

Unlike many other spider species, the hobo spider is not sexually dimorphic. This means there is no difference in appearance between males and females. While females are slightly larger than males, they are both brownish red with a herringbone pattern on their abdomens.

The hobo spider prefers to live in gardens, fields, and bushes. A hobo spider bite can cause significant pain, and there are a few cases where the bite causes tissue death but does not generally cause serious issues.

4. Bold Jumping Spider

daring jumping spider on a leaf
Bold Jumping Spider on a leaf | image by glennberry via iNaturalist

Scientific Name: Phidippus audax

The bold jumping spider can grow up to 15mm in length and is black with white lines and spots. These spiders can be found virtually anywhere in Idaho, including gardens, cars, homes, and other buildings.

As a member of the jumping spider family, the bold jumper can leap up to four times its body length. It uses this talent to pounce on unsuspecting prey.

5. Triangulate Cobweb Spider

Triangulate cobweb spider
Triangulate cobweb spider | image by u278 via Flickr

Scientific Name: Steatoda triangulosa

This small spider is commonly found in homes around Idaho. Looking around the windows and lights or in low-traffic corners in your home, you may see a triangulate cobweb spider.

Triangulate cobweb spiders are covered in tiny hairs and are yellowish-orange with yellow legs. Though common, these spiders are not usually aggressive and do not pose any threat to humans.

6. Western Spotted Orbweaver

Western spotted orbweaver on a cobweb
Western spotted orbweaver on a cobweb | image by Katja Schulz via Flickr | CC BY 2.0

Scientific Name: Neoscona oaxacensis

The western spotted orbweaver spins an orb-shaped web, and it sits in the middle of the web, waiting for its prey. This spider has a large gray or black abdomen featuring small, cream-colored markings.

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Each of its eight legs has tiny hairs and bands of yellow and cream. The female is larger than the male and can reach up to ¾ of an inch in length.

7. Cat-Faced Spider

Cat-faced spider
Cat-faced spider | image by James St. John via Flickr | CC BY 2.0

Scientific Name: Araneus gemmoides

The cat-faced spider ranges in color from light beige to dark brown. They get their name from markings on the top side of their abdomen that resemble a cat’s face. As with most spiders, the female is significantly larger than the male and can grow up to 25mm in length.

Cat-face spiders are members of the orbweaver family, so they build circular webs to catch their prey. These spiders are not known to be harmful to humans.

8. Long-Legged Sac Spider

Long-legged sac spider
Long-legged sac spider | image by Judy Gallagher via Flickr | CC BY 2.0

Scientific Name: Cheiracanthium mildei

The long-legged sac spider builds silk sacs on the ceiling, in the corners of buildings, and under beds. The spider does not use these sacs as a web for catching prey; they use them to rest during the day.

They are nocturnal, so they go out at night to hunt their prey. Though venomous to humans, their bite is not lethal. It can cause some pain and heal slowly, but it is not life-threatening.

9. Barn Funnel Weaver

Barn funnel weaver
Barn funnel weaver | image by Nikk via Flickr | CC BY 2.0

Scientific Name: Tegenaria domestica

The barn funnel weaver is a close relative of the hobo spider and has similar characteristics. Adult females can reach up to 11.5 millimeters, and males can reach up to 9 millimeters in length. Both are brown, like the hobo spider, with a herringbone pattern on their abdomen.

Barn funnel weavers are smaller than the hobo spider and tend to be darker in color. Though a bite from a barn funnel weaver will likely hurt, it does not pose any real threat to humans.

10. Cellar Spider

Long bodied cellar spider
Long-bodied Cellar Spider | image by Judy Gallagher via Flickr | CC BY 2.0

Scientific Name: Pholcus phalangioides

Cellar spiders are known for their small bodies and long legs. Their bodies are less than half an inch long, but their legs are up to two inches long.

They are different shades of brown with the thorax usually a lighter shade than the abdomen. These common spiders in Idaho are found in homes and buildings, especially in cellars and basements.