Sac Spiders

Sac spiders are known by their tendency of making sacs, instead of webs. The sac is used for daytime retreating. Generally, the spiders are nocturnal. There are 16 genera, including 708 species.

Spiders Belonging to this Family

Genus

Cheiracanthium

Species

Yellow Sac Spider

Physical Description and Identification

Adults

Size: Sac spiders are generally 0.19-0.39 in (0.48-0.99 cm), but this an average size of female spiders as males are smaller than females.

Color: From pale brown to yellow, the sac spiders exhibit such shades, sometimes similar to some of the recluse spiders.

Other Characteristic Features: The spiders of this family have 8 eyes, set in 2 rows.

Eggs

Sac spiders create egg sacs, sometimes multiple, and then prepare themselves for laying eggs inside the sac.

Spiderlings

After hatching, spiderlings usually stay at the sac for a few more days, sometimes with their mothers. After a certain period, they leave the sac and start living alone.

The Web

Sac spiders do not make webs as they are natural hunters. They can make silken retreat although, but not necessarily a web.

Are Sac Spiders Venomous

Sac spiders have venom that is only effective on their preys. As far as humans are concerned, the spiders do not attack them, until threatened. Their bite is not detrimental, but it causes swelling and redness. The intensity of the pain depends on individuals.

Quick Facts

Distribution Asia, Europe, Africa
Habitat Gardens, leaves, woods
Diet Insects and at times their own eggs as yellow sac spiders do
Lifespan 1-2 years

Did You Know

  • There are many spider species that have the common name of sac spider other than the member of this family.