Spiders Spiders can be found in all environments throughout the world, except in the air and the sea. (Biology of spiders, R.Foelix) These invertebrates of the order Aranea are one of the numerous groups of the class Arachnida, with approximately thirty-four thousand species. Their body size ranges from a few millimeters in length to nearly five inches. They are all carnivorous and have four pairs of walking legs, a pair of pedipalps and a pair of chelicerae. (Spiders, W.Shear) Each chelicera consists of a base and a fang. The fang folds inside a groove in the base until it is needed to attack food, then moves out to bite and releases venom from a small opening at its end as it enters prey. (Biologia Dei Ragni, R.Foelix) They are also used for "chewing", bringing the digestive juices inside the body of the prey and then squeezing the meal liquid. The pedipalps are used primarily to capture and rotate prey while the chelicerae inject venom into it to break down tissue. Subsequently the bases of the pedipalps are used as chewing parts. (The Spider Book, J.Comstock) But in males, these palps are used to transfer sperm into the female. These twelve appendages are attached to a dorsal and ventral plate, carapace, and sternum that cover the entire prosoma and provide attachment points. The body of spiders is made up of two parts, an anterior portion called the prosoma and a posterior portion called the opisthosoma. These two portions are held together by a narrow stalk called a peduncle. This tight junction allows the spider to be very agile and acts somewhat like a hinge between the prosoma and the opisthosoma. Thus, as a spider moves forward creating a web, it can continue in a straight line casting the web in the direction it chooses. This is how spiders create their zigzag web formations. (Biology of Spiders, R.Foelix) Lining both the prosoma and the opisthosoma is a waxy covering which allows the spider to be a very efficient water conservator. This is one of the characteristics that spiders have developed to adapt to the harsh conditions of terrestrial life. There are eight eyes located in the head region, usually in two rows, which vary from family to family. Spiders that wait and lunge for prey will have a row of very large eyes well adapted to detecting the precise distance to prey. Yet those spiders that spin webs do… middle of paper… bush and attack their prey. They also have a large set of eyes in the upper back row, above a row of four generally small eyes. Although wolf spiders have well-developed eyes, they mainly react to vibrations received from the beating of their wings or the movement of insects on the ground. As with jumping spiders, there are a large pair of fangs that extend downwards to help capture prey. The best-known wolf spider is the tarantula. These spiders can reach up to ten inches in their full length. And although tradition has it that they are one of the most venomous spiders, their bites are only painful to humans, not deadly. (Biology of spiders, R.Foelix) Although the feeding habits of spiders vary, their methods of reproduction are all relatively similar, although each species has its own specific ritual. Since spiders are cannabilists, the much smaller male must be very cautious when approaching a potential mate. If he simply rushes towards the female, he is likely to be seen only as food and consumed. So spider courtship has evolved into a special and complex pattern that varies in each species. This variation allows the recognition of the species, therefore not