Maybe it’s because they have so many legs. Maybe it’s because most of them have more than two eyes. It could be the way they seem to float down from the ceiling and land on the unsuspecting. Whatever the reason, spiders frighten a lot of people. Spiders are so spooky that they have become popular Halloween decorations. But, what are the facts? Are spiders really as scary as they seem?
Spider Anatomy
Spiders come in many sizes and colors, but all spiders have the following characteristics: eight legs, two body parts, and sharp pointed jaws called fangs. The two parts of a spider’s body are the cephalothorax and the abdomen. The legs are jointed, arranged in pairs around the cephalothorax and have either two or three claws. 99% of spiders have eight eyes arranged around the cephalothorax, but the remaining 1% have as many as six or as few as two.
• Anatomy of a Spider: A photograph of a spider with various parts labeled.
• Arachnid Anatomy: An overview of external spider anatomy.
• Unique Anatomical Characteristics of Spiders: An anatomical diagram of a spider.
• What Do Spiders Look Like?: Photos and descriptions of common spiders.
Spider Species
There are over 38,000 species of spiders around the world and over 3,000 different species in North America. The scientific names of spiders tend to be difficult to pronounce. For example, achaearanea tepidariorum is the scientific name for the common house spider. A wolf spider’s scientific name is lycosidae. Spider families are diverse. It is estimated that the jumping spider family includes over 4,000 species worldwide, sheet web spiders over 3,000, orb weavers over 2,500, and wolf and crab spiders over 2,000 each.
• Spiders: Facts about spider history and species diversity.
• Species Names: (PDF File) Common and scientific spider names.
• New Spider Species: The story of how a new jumping spider species was discovered by students.
• Identifying Spiders: What to look for when identifying a spider species.
Spider Bites
One of the spookiest things about spiders is that they all have venom and are capable of biting. Fortunately, there are very few spiders that are powerful enough to bite through human skin. Most people think of tarantulas and black widows when they think about dangerous spiders. Neither of these spiders are aggressive and usually will not bite unless provoked. The fact is that most spiders have no interest in humans and, if left alone, will not strike out.
• Potentially Dangerous Spiders: Photos and descriptions of spiders that bite people.
• Identifying and Treating Spider Bites: What to do in case of a black widow spider bite.
• Preventing Spider Bites: Ways to protect yourself from being bitten.
• Spider Bites and Scorpion Stings: What to do in case of a venomous spider bite.
Spider Webs
While all spiders make silk, not all spin webs. Most spider webs are spun to capture prey. Jumping spiders and wolf spiders capture their prey without using snaring webs. Of the spiders that do spin webs, there is great diversity. Orb weavers spin webs that tend to look like a circular grid and are the type usually copied for Halloween decorations. Some of these webs can be quite large. Most web spinning spiders build several webs a season, some even eating the silk of the previous web. Spider webs conjure up all kinds of creepy feelings, but the truth is that spiders provide a valuable service with their webs by preying on pests such as mosquitoes, aphids, flies, and grasshoppers.
• The Spider Web: The different uses of a spider’s web.
• Fall Spiders and Their Amazing Webs: Learn about orb weavers and how they spin their webs.
• The Beauty of Spider Webs: Photograph and information about spider silk and web formation.
• Garden Spiders: Photographs of a black and yellow garden spider in its web along with some interesting facts.
Written by Michael S. Atwood