The Yellow Sac Spider

Yellow Sac Spider by Vengolis – Own work, CC BY-SA 4.0
The Yellow Sac Spider (scientific name- Cheiracanthium inclusum and Cheiracanthium mildei) is those house spiders which instead of making a web, usually prefer constructing sacs in protected areas – hence the name yellow “sac” spiders. These spiders are very common in the United States and decrease in numbers as we move towards the cold, northern regions. Often confused with brown recluse spider bites, their bites sting as much as that of wasps but are much less severe than either of them.
HOW TO IDENTIFY YELLOW SAC SPIDERS
If the spiders you are seeing in your house have the following features, you can be sure that they are the yellow sac spider:
- Pale beige to yellow in color
- May have a tinge of green as well, with fangs and tips of legs dark brown in color
- Dark, lance-shaped mark covers major part of it abdomen (top view)
- Length differs from 5mm to 10mm for both, males and females
Appearance, Behavior, and Signs
- Usually avoiding human contact, but in case they sense danger, they are quick to jump from the walls to the ground and scatter
- Most active at night time, these spiders hunt for their prey instead of waiting near their sacs
- At daytime, they prefer to stay in their constructed sacs and use this place for: molting (shedding their outer skin so as to grow larger in size), mating, laying eggs, and hibernating (sometimes in winters)
- During summers, they can be generally found on trees, shrubs, and in agricultural lands. Occasionally, cotton crops too. Their eggs generally hatch in winters, wherein they start their transitioning phase till spring season
- Breeding usually takes place during summer season, with males hunting for females to mate with. Females mate less but produce as much as five sacs with approximately 40 eggs in each one of them
- The sacs which are constructed are not only for protecting the eggs but also immature (phase) and mature spiders
- The possible chances of a human being bit by such spiders is if they are trapped between a person’s skin and bed sheets, clothing, shoes or in gardens/ fields
- Their bites can be painful and may damage tissues on the area infected. Their bites may result into soreness, itching and swelling and it generally takes 2-3 weeks to heal completely. However, these are definitely not something to sweat about since they cause no further damage