Are There Venomous Spiders in the UK?

Yes, the United Kingdom has over 650 different species of spiders, 12 of which are venomous enough to cause humans a certain amount of pain. The most feared spider in Britain is the notorious false widow spider (Steatoda nobilis), the most dangerous British spider Also known as the cupboard spider, the false widow can cause pain and even flu-like symptoms in some cases. Despite this it is not a killer.

There are three other venomous spiders in the UK, including the cardinal, woodlouse, and tube web spiders. While many spiders may have venom, not all are able to pierce the thick skin of a human and envenomate a person. Most of them will be using their venom to kill or incapacitate very small prey.

It is important to know there are no poisonous British spiders. Spiders are venomous, not poisonous. This means they have venom glands which produce a toxin which is introduced to another via envenomation. Poisonous animals are those which have toxins that are passed through touch or consumption. In this way, we will not have any problem if we are simply touching British spiders, but we will need to be careful we are not bitten.

With this in mind, we share the different types of venomous spiders in the UK.

The false black widow (Steatoda nobilis), usually called just ‘false widow’, is a fearsome arachnid that gets its name because it can be mistaken for the more dangerous black widow (Latrodectus spp.).

This is the most venomous spider in the UK. Its venom can lead to intense localized pain, in which a small degree of inflammation is observed. It may also cause numbness, discomfort, a burning sensation and chest pain. In rare cases, extreme nausea may be experienced. In case the spider bite is infected, it can cause related medical conditions such as gangrene. However, experts opine that there is no way a false widow bite can instigate an infection bad enough to lead to death. Only female false widows can cause pain to humans.

The false widow is not a native of the British Isles, but from the Canary Isles. However, it arrived to the United Kingdom in the 19th Century, where it was observed during the summer in the southern and eastern coasts. On account of climate change, the range of the false widow is spreading north.

These spiders usually measure about 10 mm, although females can be larger. They are dark brown in color, with paler markings, and have a bulbous and swollen abdomen.

The green-fanged tube web spider or cellar spider (Segestria florentina) is gets its name because its web is tube-shaped. It is the largest species of this kind in Europe. It was introduced into the United Kingdom from the Mediterranean by traders; the adults are out from June to November. You can find tube web spiders in urban areas, especially in the cracks of buildings.

While cellar spiders can prove to be aggressive when in attack mode, their bites can be treated medically. Intense pain is felt on being bitten by this arachnid species, but it subsides within 5 to 6 hours. Male cellar spiders are around 15 mm, but females can surpass 20 mm.

Image: flickr.com

The woodlouse spider (Dysdera crocata) gets many other names, including sowbug killer, woodlouse hunter and slater spider, all names basically referring to the fact that it eats woodlice. While we will never be considered their prey, under extreme provocation, such as direct handling, the woodlouse spider can bite humans. Its venom only causes mild itchiness.

This venomous spider comes originally from southern Europe, but it has managed to reach many different shores, including those of the British Isles. The woodlouse spider has a colorful appearance, with three pairs of eyes, a dark reddish body, and a yellowish brown abdomen. It is about 15 mm long, although females can reach twice that size.

The cardinal spider (Tegenaria parietina) is easily one of the largest house spiders in the British Isles. Its leg span can be of more than 12 cm (4.70"), although its body is quite small in comparison. The common name of the cardinal spider comes from the legend that says this spider frightened Cardinal Thomas Wolsey in the Tudor era at Hampton Court.

These arachnids have a bad reputation on account of their massive size and predatory nighttime behavior. Although the cardinal spider is technically venomous, its bites are rare and quite painless.

The money spider is not a species, but members of the taxonomic family known as Linyphiidae. It includes more than 4,000 species, many of which are widespread across the UK. Also known as sheet weavers, money spiders look for damp vegetation. Most bites happen to people working in wet weather or on building sites. These spiders bite their prey to induce paralysis, but they only cause localized redness and inflammation to humans.

Money spiders are very small, usually less than 3 mm, and their bites don't always penetrate human skin. They are given this moniker because it is believed that if one is stuck in your hair or clothes, it brings increased luck and money.

Image: flickr.com

The walnut orb-weaver spider (Nuctenea umbratica) is found in North Africa, some regions in Asia, and most of Europe, including the UK. It inhabits the shaded places behind barks and crevices in the woodwork during the daytime.

This is one of the venomous spiders in the UK, as its bite leaves burning pain which can run from the finger to the elbow. There will also be a red spot with white inflammation. It can cause the arm to go numb if bitten on the hand. Recovery occurs within a few hours, though. Male walnut orb-weaver spiders reach 8 mm, and females can double that size.

The black lace-weaver (Amarobius ferox) can be found all year long in North America and Europe. It is relatively big, at around 11 to 15 mm. It is almost black in color, with a bulbous abdomen.

This is indeed a venomous British spider. The bite of a black lace-weaver results in pain and a white patch with reddish appearance around it. The swelling lasts for a period of three days on an average, accompanied by nausea.

The wasp spider (Argiope bruennichi) inhabits almost all continents, although it is a new British spider species and rare to the United Kingdom. In Britain, this venomous spider can only be found in the months of June to September.

Female wasp spiders reach 15 mm, while males barely grow to 5 mm. They are black, yellow and white, with a stripe pattern that gives them their name. The bite of a wasp spider causes immediate pain, which can spreading from the hand to the groin.

Also known as the cross spider, diadem spider or orangie, the European garden spider (Araneus diadematus) can be found in Europe and North America. It is also present in the British Isles from June to November.

Their size varies. Male garden spiders can measure from 5 to 13 mm, and females can measure 6 to 20 mm. They can be recognized by a cross pattern or mottling in white on their backs. Although they only bite when threatened, they can cause pain, nausea and inflammation for 2 to 3 days.

Careful with this one. The mouse spider (Scotophaeus blackwalli) is a venomous spider you can find in the UK is not actually harmful, but the unrelated Australian mouse spiders (Missulena) are.

The missing sector orb weaver or silver-sided sector spider (Zygiella x-notata) is so called as it spins an orb web without one entire sector. This is a medium-sized spider, at 15 mm, that can be found in houses and gardens across the UK. This spider is seen indoors in the winter and autumn months, as it prefers warmth.

Despite being venomous, this spider is harmless to humans. It is known for its pale body and legs, with silver-grey markings on the abdomen.

Image: lightscapes.info

The cupboard spider or false black widow (Steatoda grossa) is often mistaken by the more venomous black widow because of its dark shades, from purple to brown, and bulbous abdomen. It can grow to around 10 mm.

This species lays between forty and hundred eggs thrice a year. Cupboard spiders are spread throughout the world, and they are among the venomous spiders of the UK. They are known to attack humans: false black widow bites can result in minor discomfort and blistering, which lasts for some days. In severe cases, there can be extended malaise and even fever.

The giant house spider (Eratigena atrica) is one of the venomous spiders in the UK. It is commonly found in British homes and wanders around in the mating season, in autumn. This species is indeed gigantic, as a female's body can reach 1.9 cm (0.7") with 4.5 cm (1.8") leg span, while males have a 1.5 cm (0.6" body with longer legs, reaching even 7.5 cm (3").

Giant house spiders can be found to run very fast, but only for a limited time before recovering. Building sheet-like webs, they are found in sheds, garages, cavity walls and attics. These spiders are venomous, but generally do not attack humans.

The longbodied cellar or cosmopolitan cellar spider (Pholcus phalangioides) is also known by the popular nickname of daddy long-legs spider. Their body length is of less than 10 mm, but their legs can reach even 7 cm (2.75 in). This spider has a comparatively tiny body and a long, thin-legged appearance, hence its name.

Unfortunately, these cellar spiders have a relatively potent venom, although not as much as folk tradition would have you believe. The good news is that their bite barely affects humans. Although they can penetrate some millimeters into our skin, we only feel some localized burning for seconds.

There are two related venomous spiders known as lace-webbed spiders because of the webs they weave. They are known scientifically Amaurobius fenestralis and Amaurobius similis. Found in walls and fences, these spiders may venture indoors in search of a mate.

Lace-webbed spiders are brown with yellow marks, and they grow to around 20 mm. Bites are relatively painful and the symptoms include localized swelling for some hours.

The zebra spider (Salticus scenicus) is a distinctive creature, with black and white marks like a zebra over its back and legs. This eight-legged arachnid reaches about 8 mm in size. It doesn't build a web; instead, it has a curious jumping stop and start motion. Interestingly, they often do so when they realize they have been noticed.

The zebra back spider is known to remain outdoors, but can venture in through open doors and windows. This spider can bite, though the venom is not life threatening or even too painful.

As we have learned there venomous spiders in the UK, but they're not very dangerous or threatening. If you're interested in local British fauna, don't miss the following articles:

• Are there venomous snakes in the UK?
• Vulnerable native dog breeds in the UK
• What are the queen's corgis called?

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