Brown spiders

The name brown spider is perhaps a bit confusing, as many spiders are brown. However, in South America, Brown Recluse Spiders are called Brown Spiders1, although it is a rather nonspecific name. This site is not only about the brown recluse, it is about the most commom and feared Brown Spiders in the world - with emphasis on North American species.

This webpage tries to give some basic information about brown recluse spiders and the most common other brown spiders one may encounter. As you will learn, you shouldn't fear spiders too much.

Common brown spiders

The best known and most common brown spiders in the US, besides brown recluse spiders are: Wolf Spiders, Grass Spiders, Hobo Spiders, Common House Spiders and Funnel Web Spiders. Here on this webpage the Brown Recluse Spider and the other five spiders are described.

Brown recluse spider

Although the chances of finding a brown recluse spider in Florida and California is close to nil, this Brown Spider, the Brown Recluse Spider, is much feared in these two states. There are no populations of brown recluses in Florida nor in California. This fact has been repeated again and again in numerous web publications - one example is here. This brown spider is very small and it is not aggressive although it will bite if mashed or if it feels treathened. Recently it was found that a family in Kansas of four had lived for years with thousands of brown recluses in their home without a single bite2. Furthermore, in Chile, brown recluse spiders are very common in many people' homes, but no incidences of bites are reported3.

Bites from the brown spider, the recluse, can be painful in those cases where the bite is not dry - and an envenomation takes place. It can be difficult to identify a brown recluse spider from many other brown spiders if you don't know the special characteristics of brown recluse spiders.

                                                                                     


A brown spider, a brown recluse spider, on a white background

                                                                           


However, there are a few things that can help you with your brown, brown recluse identification. First of all recluses have six eyes that are arranged in pairs whereas most other brown spiders in the US have eight eyes. Secondly, their abdomen has a uniform color without any patterne. And their legs are covered with very fine hairs but lack spines.

Grass spiders

Grass spiders are harmless brown spiders related to funnel web spiders. Their body can reach a length of 0.8 inches. They have a characteristic large, non-sticky web with a funnel on one edge. They have light and dark stripes near their head. They are mostly found outdoors, and as said before, they are completely harmless.

A brown spider, a grass spider, looking scary

Wolf spiders

Wolf spiders are another type of brown spiders that are in fact rather harmless although they are venomous. They do not build webs and as sight-hunters they hunt down their prey rather than entangling the prey. Females carry their egg sacs with them on their abdomensm which is an unique characteristic of wolf spiders. Some people like to go on wolf spider adventures where they have fun running around with flashlights; wolf spiders eyes are particularly good at reflecting light.

A brown spider, a wolf spider, eith egg sacs (its a female)

Some wolf spiders hide in burrows where they sit and wait for a prey to get close enough for a hunt. Other wolf spider species hide under rocks and in crevices inbetween rocks. Their size varies quite a deal. Please consult the picture section for photos of brown wolf spiders.

Common house spider

The common house spider is another brown spider. Only females are venomous although most bites from females too ends up as dry bites without envenomation. They are cob-web spiders and entangle their prey in their webs, subdue it (paralyzation) and eat it. The diet consist mainly of insects and other invertebrates. To have some common house spider in a home may actually be beneficial as they keep populations of household pests at low levels.

A brown common house spider with long hairy legs

As they are often found in homes they are used to being with humans. They won't bite unless they feel treathened and they do not pose any risk even though some bites are venomous.

Funnel web spider

Australian funnel web spiders are extremely venomous and one should be very careful handling funnel web spiders of Australian origin. The funnelweb spiders found in the US are not nearly as poisonous, although hobo spiders, a type of funnel web spiders, are rather venomous. Grass spiders are also funnel web spiders and they are harmless.

A funnelweb spider

At one end its web contains a funnel whereto the spider can escape at both ends. The funnel is also the place where the spiders consumes its preys. Often it just sits inside its funnel and waits for vibrations in its web indicating that some insect has been caught. Funnel web spiders are brown spiders and they are often mistaken with wolf spiders. Wolf spiders does not build webs at all, so if you see a brown spider and you don't know if its a funnel web spider or a wolf spiderm you can always exclude that its a wolf spider by seeing if it sits in a web. Funnel web spiders are very fast as are hobo spiders.

Hobo spiders

Hobo spiders was imported into USA by ships entering ports on the west coast, probably Seattle in Washington. Since then they have gradually spread to other parts of Western USA, and they can be found in Oregon, Northern California, Oregon, Idaho, Montana, Utah, Wyoming and of course Washington.

Hobo spiders are quite large and they move relatively fast. Hobo spiders are indeed brown spiders and they have a chevron pattern on their abdomen.

During the summer and early autumn males are searching for males. As they run quite fast, don't be surprised when you see a large male hobo spiders running across your floor in look for female to mate.

A non-dry bite from a hobo spider, and an envenomation, result in something called tegenarism. Sometimes people think they have been bitten by a brown recluse spider in cases where it really was a hobo spider.

References

1. Vetter, RS & Isbister, GK Medical Aspects of Spider Bites Annual Rev. Entom. 53: pp 409-429 (2008)

2. Vetter, RS & Barger, DK An infestation of 2055 brown recluse spiders (Araneae: Sicariidae) and no envenomations in a Kansas home: implications for bite diagnoses in nonendemic areas. Journal of Medical Entomology 39: pp 948-51 (2002)

3. Schenone, H. Rojas, A. Reyes, H. Villarroel, F. Suarez, G. Prevalence of Loxosceles laeta in houses in central Chile Am. J. Trop. Med. Hyg. 19: 564-67 (1970)

Acknowledgements

Thanks to David, Gerardine, Charles, Lisa, Jon and Sean for giving me the permission to use their photos.


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