What Group of Animals Do Spiders Belong to?
Spiders are part of the Arachnida, a large group of animals that includes arachnids, mites, ticks, scorpions, and crustaceans. There are over 45,000 species in the arachnid family, including spiders and their relatives. They have eight legs and no antennae.
Spiders are carnivorous and usually eat insects. Various arachnid groups also produce venom. Some arachnids even eat plants.
Many spiders have elaborate webs, varying in shape and thickness. Spiders can reach up to 90 cm in size and are found in almost every continent. However, most sea spiders are small, with only a few deep water species reaching over 90 cm.
The most common arachnid is the house spider. Its body is divided into two sections: a head and thorax, and a abdomen. The abdomen has leg-like structures, called pedipalps, and the chelicerae, a segment containing venom sacs.
In addition, spiders have an open circulatory system, with no venous blood. This makes them more similar to solifuges. Spiders are also unique in that they lack extensor muscles in their limbs, which allows them to extend their bodies by hydraulic pressure.
Most arachnids are scavengers and feed on the pre-digested bodies of insects. Several species of arachnids have a minusculoscis, a suck-hole. Using this hole, they suck liquids from their prey.
In addition, most spiders produce silk. Silk is used for many purposes, such as wrapping prey, climbing, and tethering for safety. But some species of spiders actually produce silk for their own use, including making cocoons to protect their eggs.