How to Identify Spiders in the U.K.

The presence of unusual coloring is one of the best markers for identification. Cucumber green and flower crab spiders have a pale green coloring. Nursery web spiders are pale tan to white. Black widow, false widow and walnut orb spiders are mostly black or nearly black, but vary in size and where they are found.

Patterns may be found on the spider's body or legs. In zebra and wasp spiders, brilliant colors and patterns are present. For the pirate spider, their banded patterned legs set them apart.

The size may be easy to judge, but often the shape of the abdomen may be more difficult to discern. Yet this serves to differentiate many spider types. For example, grass spiders have a long, thin body, while a missing sector spider has a bulbous abdomen.

Spider behaviors are a helpful tool in identification, but should not be considered positive identifiers without other information. In some cases, location or distribution, the time of the year a spider is most often seen and the food eaten by a spider can offer clues to its identity when the actual spider is difficult to spot.

Web construction can be used in spider identification. The type and shape of the web, the purpose of the web or whether a web is produced at all can be used to include or eliminate possible spider suspects.

Web labyrinth spiders make a sheet style web and form a funnel at one end, while a very similar looking nursery web spider creates a silk tent for spiderlings, but no true web.

Tube web spiders are known to be aggressive. While not every bite comes from an aggressive spider, it may be possible to identify certain spiders based on their bite or the resulting reaction.

The Natural History Museum in the UK keeps a record of bite reports and reminds people that, although spiders are not considered a danger in the UK, there are over a dozen which can cause a significant problem with their bite.

False widow bites have caused a marked reaction with swelling and intense pain which progressed over the course of days. The bite of this spider has also resulted in the rapid appearance of a throbbing form of swelling.

There are fewer reports concerning the cross spider, but significant swelling has resulted from its bite; lace weaver bites have produced less significant swelling. A bark sac spider bite can produce a blistered rash while a mouse spider bite has been known to develop a nasty wound with septic development and inflammation.