For the most part, these are male House spiders (Tegenaria species) and they are on the prowl and filled with intent! They are on the search for females and will explore every corner of your house looking for the lady spider of their dreams.
It is quite easy to work out the gender of a house spider. The males have smaller bodies but longer legs than the females and the palps (like tiny legs either side of their jaws) look like little arms with boxing gloves. They are the ones more prone to running across your carpet.
The female palps are slimmer and the body can be twice as big. Females tend to stay put in their webs, which might be located behind a bookcase or in an air vent. It is very much a case of come and find me fella!
The species of house spider you get will partly depend on where you live. In the south-east it tends to be Tegeraria gigantea. In the west it tends to be Tegenaria saeva and in the north it could be either of these two or even hybrids (where the two species have interbred). The smaller Tegenaria domestica is found everywhere but may be declining as the larger species spread north.
House spiders are basically harmless but if you don’t like to cohabit with them, we recommend you use a humane spider removal device and release them into your garden.
Tegenaria Male © Steven Falk