House spiders are common unwanted guests in homes around the world. While many people dislike having spiders in their house, these arachnids usually cause no harm and perform the beneficial service of catching insects. Still, homeowners often wonder – how long will a spider stick around once it moves inside? Let’s take a look at house spider behavior to better understand their tenure as housemates.
Typical House Spider Species
There are a few spider species most commonly found within homes:
- Cellar spiders
- Jumping spiders
- Funnel weavers
- Cobweb spiders
- Fishing spiders
- Wolf spiders
- Parson spiders
- Sac spiders
Many of these spiders wander into houses by accident, so their time indoors is not necessarily part of their natural behavior. However, some species like cellar spiders intentionally seek out buildings and human homes to build webs and hunt prey.
Why Spiders Come Indoors
Spiders venture inside homes for several key reasons:
- Food is abundant indoors – houses contain lots of insects for spiders to eat
- Indoors provides safety from predators like birds and wasps
- Indoors offers shelter from harsh weather outside
- Some species like cellars and attics as ideal places to spin webs and lay eggs
Basically, the conditions inside homes are very attractive to many spiders looking for sources of prey, protection, and suitable habitat for reproduction.
How Long Do House Spiders Stay Inside?
Most house spider species do not permanently live indoors. Their time inside depends on the following factors:
Some spider varieties are more adapted to outdoor living and will quickly leave a building, while others are more content residing in man-made structures for long periods. Cellar spiders, cobweb spiders, and sac spiders often stay in houses for the entirety of their lifespans.
Availability of Prey
Spiders will linger indoors as long as there are adequate prey sources. Once indoor insects become scarce, spiders are prompted to exit in search of better hunting grounds.
Spiders favor indoor areas with suitable habitat features like undisturbed corners with crevices, cracks, or holes where they can build webs and egg sacs. They will depart once conditions become too inhospitable.
As seasons change outdoors, some spiders will leave houses to find better outdoor niches while others will be driven inside by worsening outdoor conditions.
Adult male spiders venture into homes in search of females, then usually leave after mating. Only gravid adult females typically try to overwinter inside houses. Juveniles and younger adults often stay indoors through summer and fall before leaving in winter.
Median Duration by Species
Here are rough estimates of the typical duration different spider species reside in homes before leaving or perishing:
|Spider Species||Typical Time Indoors|
|Cellar Spiders||Several months to a full year|
|Jumping Spiders||A few weeks to 2 months|
|Funnel Weavers||2-3 weeks|
|Cobweb Spiders||Many months|
|Fishing Spiders||A few days to weeks|
|Wolf Spiders||Up to a month|
|Parson Spiders||1-2 months|
|Sac Spiders||Several months to a year|
Do House Spiders Permanently Live Indoors?
Most house spiders do not permanently live their entire lives inside human homes. There are a few exceptions:
Cellar spiders commonly spend their full lifespan inside houses, rarely venturing outside once indoors. Homes often contain plenty of small insects for them to eat year-round. These spiders frequently build messy-looking tangle webs in corners or windows.
Cobweb spider species like the common house spider also frequently reside permanently indoors. They build sheet-like webs on walls, in corners, or behind furniture to snare prey. Homes suit them well as permanent habitat.
Sac spiders often overwinter inside houses and may never leave. They make silken tubes or sacs in secluded indoor spaces. Their lifespan is up to 2 years.
Toward the end of summer, some female spiders will find protected indoor areas to spend the winter and lay eggs very early spring. These overwintering spiders remain inside permanently.
Do House Spiders Return?
Most house spiders that leave will not return again once they have departed. However, there are some exceptions:
Newly Mated Females
Female spiders that mate indoors, leave, and produce an egg sac outside may return inside a house multiple times to lay more eggs. Each time, they carry their egg sac indoors to find good overwintering spots.
Following Prey Sources
Spiders that periodically follow certain insect prey as they move in and out of a home may make repeated returns. Certain spiders are adept at tracking down transient prey.
Seeking Winter Shelter
Some spiders driven outdoors in summer will return to their previous indoor winter shelter sites come fall as temperatures drop. They remember locations that served them well the previous winter.
Annual Mating Males
Adult male spiders may return to places like basements where in previous years they had success finding female mates. These spots are in their memory as productive breeding sites.
Will Killing Spiders Reduce Their Numbers?
Killing indoor spiders unfortunately does little to reduce their numbers in a home long-term. Here’s why:
- Open doors and windows allow new spiders to easily enter
- Eggs left behind hatch into more spiders
- Outdoor spider populations remain high
- Their prey – insects – continue moving in and out
- Nearby outdoor spiders will move inside a vacant spider-free home
- The home still offers good habitat with food, shelter, warmth, water
The endless supply of insects and the inviting indoor conditions will ensure more spiders inevitably keep coming, despite efforts to kill them. Non-toxic deterrents and sealing cracks are more effective than killing.
Will Spider Numbers Decline in Winter?
Spider populations do decline inside homes during winter for a few reasons:
- Many spiders either die off or leave seeking warmer spots
- Lower temperatures cause a slower metabolism and inactivity
- Few insects are available as prey
- No mating occurs so numbers remain lower
- Egg-laying ceases until springtime
- Colder weather drives many species outdoors or into hibernation
So while a number of spiders may overwinter inside, overall populations dwindle indoors during the winter months. Their activity and reproduction remains minimal until warmer weather returns the following spring.
Most house spiders only temporarily share our homes, staying weeks or months before leaving. Their time indoors depends largely on food availability, habitat suitability, seasonal conditions, and life stage. A few species like cellar spiders, cobweb spiders, and sac spiders often reside in homes permanently or overwinter there. While spider populations drop when it gets colder, their numbers inevitably rebound when conditions again become favorable indoors. Though killing spiders may offer temporary relief, the best way to reduce encounters long-term is sealing cracks and crevices around your home’s exterior. With proper proofing and deterrents, spiders can be discouraged from ever moving in at all.