School Will Be Closed Today—Due to Spiders

student spiderAs the parent of school-age children, I have learned to dread that early morning call with the cheerful recorded voice that informs me that school has been canceled or delayed. Here in Wisconsin, these calls are almost always a result of inclement weather, and if we pay attention to the weather forecast, we typically know the night before that a delay or cancelation is a possibility.  Every once and awhile though, that call comes unexpectedly. On those mornings, while our kids dance around like deranged snow-bound monkeys, my husband and I drag out phones and calendars and begin the process of deciding who will be snow-bound with the monkeys, and who will escape go to work. However, even these unexpected snow days can’t really be called a great surprise. Snow days are a geographic risk of living in an area that has snow several months out of the year. I wonder, though, how my family would react if we got a call announcing school would be closed for the day due to a venomous spider infestation.

I know what you are thinking. This sounds like a bad horror movie; after all I am posting this on Halloween, a day associated (in the United States, at least) with all things creepy and crawly. Unfortunately for the parents and students of one school in the UK, this is a case of life imitating a bad horror movie. Last week, The Dean Academy in the Forest of Dean sent a letter to parents announcing that as the result of an influx of the venomous False Widow Spider (Steatado nobilis) the school would be closed on Wednesday (October 23) so that it could be fumigated.

The False Widow Spider is Britain’s most venomous spider. Although that sounds pretty intimidating, it turns out that the False Widow Spider is not all that venomous. This video by the Natural History Museum is part of their 2007 film documenting the rise of the false widow spider in the UK featuring Stuart Hine.

The False Widow Spider’s bite is no stronger than the sting of a bee or wasp, and it is less lethal than either of them. The symptoms of a False Widow Spider bite can range from numbness, severe swelling and discomfort to burning or chest pains. The severity of the symptoms is related to the amount of venom that was injected. They are also not an aggressive species, and are most likely to bite if accidentally squashed or prodded perhaps when they become trapped in clothing. There has never been a documented death in Britain as the result of a False Widow Spider bite.

Clearly if a school was infested with bees or wasps, we would want them to be removed before we felt comfortable sending our kids to school there. Infestation with a venomous spider (even a mildly venomous one) warrants the same precautions I would think.

There are, however, worse spiders in the world. For example, the Brazilian Huntsman Spider Phoneutria fera, which has the most active neurotoxic venom of any living spider. Its venom is so potent that 0.006 mg (0.00000021 oz) will kill a mouse. These spiders are large and highly aggressive and will hide in clothing or shoes. When disturbed they bite furiously and can inflict multiple bites.

So those of you in the UK can breathe a sigh of relief that your only venomous spider is relatively harmless. And those of you in Brazil? I would check my shoes if I were you…

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Kelly Grooms

Kelly Grooms

Scientific Communications Specialist at Promega Corporation
Kelly earned her B.S. in Genetics from Iowa State University in Ames, IA. Prior to coming to Promega, she worked for biotech companies in San Diego and Madison. Kelly lives just outside Madison with her husband, son and daughter. Kelly collects hobbies including jewelry artistry, reading, writing and knitting. A black belt, she enjoys practicing karate with her daughter as well as hiking, biking and camping.


  1. LOL! Thanks for the video, Alan. Although this is also called a Huntsman spider and is venomous, it is not considered dangerous to humans (thankfully for this gentleman). Despite the similarity in names (Huntsman) the Brazilian Huntsman spider and this Huntsman spider actually belong to two different families (Ctenidae and Sparassidae, respectively). Still, you wouldn’t catch me up on a ladder with a bowl trying to catch that monster!

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