If you live in the UK and find a big spider in your home, you might be seeing one of these scary-looking giant arachnids, known as the giant house spider. It is the larger cousin of the house spider (Tegenaria domestic) and is one of the largest and most common spiders found in the UK, which loves to inhabit homes and buildings, regardless of whether people occupy these buildings or not.

You may want to bring yourself up to scratch with this UK house spider, because you’ll most likely come across one in your home at some point.

Identification

A giant house spider is not very difficult to identify, even though there are several very similar species of house spider.

Eratigena atrica are large and brown with dark hairy bodies, with an abdomen up to 1 inch long. They have three rows of dark bands on their body. A pair of long, spiny front legs give them their name. The legs are nearly as long as the body.

Mature males have swollen palps that look like boxing gloves at the end of each leg. Females have a prominent silk-lined egg sac in late summer.

In terms of size, the giant house spider (UK) has been known to display a leg span of up to 120mm wide (which is about the diameter of a Compact Disc!). Female giant house spiders are larger than males, and will also live for several years, usually outliving males.

Domestic house spider hanging on the wall paper

Where do giant house spiders hide?

The giant house spider is commonly found living in warmer climates where they can (reluctantly) live outside, and prefer to live inside houses and buildings.

Mainly in early autumn, they may be encountered in most buildings where the right conditions exist, such as dark places, walls, window sills, basements, and are frequently found under dustbins and may get into baths. They may get inside lofts if their entry point is something like a wall cavity or underneath garage doors. It is more likely that they will get into warm warehouses but can also survive in domestic houses if enough heat can be retained during colder periods in winter by opening windows.

Eratigena atrica are sometimes found in neglected corners of rooms, on windowsills, and in other enclosed spaces. They build their webs in dark corners of buildings with little interference from other living beings. These sheet-like cobwebs can be so large that they may even connect multiple buildings to each other.

Lastly, you might see them darting around, as they are one of the fastest invertebrates, being able to run as fast as 0.5 metres in less than a second.

What do giant house spiders eat?

The giant house spider feeds primarily on other arthropods, which it hunts at night when they are active. They also tend to feed on flies, moths, and crickets, but some suspect they sometimes eat small birds in the wild too.

The spider will typically wait close to unsuspecting insects and then quickly immobilises its prey by injecting venom through its fangs, before wrapping it in silk to carry back to its secluded lair, where the food will be eaten later.

Female giant house spider (Eratigena duellica) feeding
Female giant house spider (Eratigena duellica) feeding on a large bluebottle blowfly (Calliphora vicina). Delta, British Columbia, Canada

Do giant house spiders bite?

Yes, they do bite people. The venom of the giant house spider is very weak, and they generally only bite when squeezed. Bites from this creature tend to happen at night or early morning as they’re nocturnal creatures.

Are giant house spiders poisonous?

Yes, but only to small insects and other spiders. The kind of venom they carry is not dangerous to humans, but it may cause pain and swelling in rare instances.

The spider is normally nocturnal and is very reluctant to bite humans. If you do get bitten by one, stay calm because it can bite quite hard. Wash the area with soap and water, which will help the wound heal quickly and stop infection from setting in. If home remedies don’t work, try going to a doctor.

So, do giant house spider bites hurt? Not really. The bite of a giant house spider is comparable to the sting of a bee, but usually no more painful than that.

This is a male Giant House Spider (Eratigena atrica)

Why do giant house spiders come inside?

These spiders come inside houses and buildings to overwinter and hide from the colder temperatures and the scarcity of food outside.

But, the question is, can giant house spiders survive outside?

Yes, they have been known to survive the harsh weather in the winter. However, many do not live for long outside. They usually try to find holes in walls or cracks in foundations where they can stay safe when the weather gets bad, and will eventually find their way back into another building if they survive for long enough.

How to keep them out for good

If you want to deter spiders, the easiest way is to mix peppermint oil and spray your home with this aroma. Also, place citrus fruits or similar smells in areas where they are frequently seen or known to hide.

Sources and References

  1. A life story of large house spiders – bbc.co.uk
  2. Spiders in your home – nhm.ac.uk

Leave a Comment

Your email address will not be published. Required fields are marked *