Sac Spider


Actual Size: ¼ to ⅜”

Characteristics: Yellow abdomen with tan legs and head

Legs: 8

Habitat: Prefers outdoor spaces but will try to get indoors in the fall when temperatures drop.


  • Known for building webs in a sac-like shape, hence the name.
  • Looks similar to the brown recluse but lacks the dark “fiddle” shape on the back.
  • Has a painful bite but is not medically significant to anybody who is not allergic.

Sac Spiders in North Jersey

Commonly called “yellow sac spiders”, these pests are known for their light-yellow coloration and habit of spinning sac-shaped webs. Though they are often mistaken for brown recluses due to their similar shape, sac spiders don’t have the same distinctive “fiddle” marking on their back, which is a good way to tell them apart. Sac spiders are a common garden pest here in New Jersey, and they primarily feed on insects or other spiders. While they tend to stay outdoors, they may also seek shelter in the winter, causing them to infest our homes.

Sac Spider Habitat

Like many other types of spiders, sac spiders are reclusive and avoid areas with a lot of human activity. They tend to stay outdoors under piles of leaves, in hedges, or surrounded by organic debris. During the fall, they may try to get indoors where it is warm, though they often stick to more remote areas like wall voids, crawl spaces, and attics. It’s also common to accidentally carry sac spiders indoors on potted plants, produce, and other everyday objects. Since they are highly adept climbers and can scale slick surfaces, they often build their webs in ceiling corners.

Sac Spider Behaviors, Threats, or Dangers

Unlike other spiders that build webs to catch prey, sac spiders build their webs for shelter or for holding their egg capsules. During the night, they go out and stalk their prey, which primarily consists of insects or other species of spiders. Sac spiders may also bite humans, resulting in a painful welt that may hurt for a couple of days. Though their bites are no fun to endure, they aren’t typically a cause for medical concern unless you have an allergy. If you notice swelling, slow healing, ulcerated sores, or are otherwise concerned about the bite, seek medical attention as soon as possible.

Struggling with sac spiders in your home or business? Call your local spider pest control technicians to get rid of them fast!