Spider

Spiders are small animals with eight legs.

Many spiders make silk. They use parts on their bodies to spin it. This silk can make webs. Some webs are sticky to catch food.

Spiders have special fangs. They use these to catch their prey. Most spiders eat things that move. One kind of spider even eats plants.

Spiders can be very different. Some live for only two years. Large spiders can live for over 20 years. They are amazing hunters.

Spiders are amazing hunters. They live on every continent except Antarctica.

A spider has two main body parts. The front part is the cephalothorax. This is where the head and middle parts join. The back part is the abdomen. A tiny piece called a pedicel joins them.

Spiders have eight legs. They do not have muscles to stretch them out. Instead, they use water pressure to move. Most spiders have fangs. They use these to inject venom into prey.

Spiders cannot eat solid food. Their guts are too narrow. They make their food liquid first. They do this by using enzymes. These enzymes turn food into a liquid. Then, the spider sucks up the liquid.

Many spiders make silk. They use parts called spinnerets to let it out. This silk can make webs. Some webs are sticky to catch insects.

Spiders can live for different amounts of time. Most live for two years. Some large spiders live over 20 years.

Spiders are amazing creatures found on every continent except Antarctica. They belong to a large group of animals called arachnids. There are about 53,680 different spider species known to scientists today. Most spiders are predators that hunt other living things. They catch insects, but some large spiders even hunt birds or lizards. One special spider, named Bagheera kiplingi, was found to eat plants in 2008.

A spider's body is built in a very special way. It has two main parts called tagmata. The first part is the cephalothorax, which is a head and middle section fused together. The second part is the abdomen, or opisthosoma. These two parts are joined by a tiny, tube-like piece called a pedicel. Unlike insects, spiders do not have antennae on their heads. They also use water pressure to move their legs instead of using muscles to stretch them out.

Spiders have a very interesting way of eating. Their guts are too narrow to swallow solid food. To fix this, they use digestive enzymes to turn their food into liquid. Some spiders pump these enzymes into their prey to melt it. Other spiders use their mouth parts, called chelicerae and pedipalps, to grind food into a pulp. Once the food is a liquid, the spider sucks it up.

Many spiders are famous for the silk they produce. They use special body parts called spinnerets to let the silk out. This silk can be used to make many different types of webs. Some spiders make spiral orb webs, while others make tangled cobwebs. Spiders have been around for a very long time. Spider-like animals appeared about 410 million years ago during the Devonian period. True spiders have been found in rocks from the Carboniferous period.

Spiders play a huge role in our world. Every year, spiders kill between 400 and 800 million tons of prey. This helps keep the number of other insects in balance. Most spiders live for about two years, but some can live much longer. For example, tarantulas can live for over 20 years. Scientists are even studying spider venom to see if it can help make new medicines.

Spiders belong to the order Araneae. They are air-breathing arthropods. They are the largest order of arachnids. Spiders rank seventh in total species diversity. They live on every continent except Antarctica. Taxonomists have recorded 53,680 spider species. These belong to 139 different families.

Spider anatomy is quite unique. Their bodies consist of two tagmata. Tagmata are sets of body segments. The first is the cephalothorax, or prosoma. This is a fusion of the head and thorax. The second is the abdomen, or opisthosoma. A small, cylindrical pedicel joins these parts. This pedicel allows the abdomen to move independently. This movement helps when producing silk.

Spiders lack the antennae found in insects. They also lack traditional jaws. Instead, they have chelicerae. These are the first appendages ahead of the mouth. Most spiders have fangs on their chelicerae. These fangs can inject venom from glands. The next appendages are the pedipalps. These are small limbs behind the mouth. In males, the pedipalps help with sperm transfer.

Spiders use a special way to move. Most arthropods use muscles to extend limbs. Spiders have no extensor muscles. Instead, they use hydraulic pressure to extend them. Their nervous systems are also very centralized. In most species, the ganglia are fused into one mass. This mass sits in the cephalothorax. This makes them highly efficient hunters.

Feeding is a complex process for spiders. Their guts are too narrow for solids. They must liquefy their food first. Some spiders pump digestive enzymes into prey. This melts the tissues into liquid. Other spiders grind prey with their pedipalps. They create a preoral cavity for processing. Once the food is liquid, they suck it up.

Spiders use many strategies to hunt. Some catch prey in sticky webs. Others use silk to lasso prey with bolas. Some spiders mimic their prey to hide. Active hunters may also run prey down. Most spiders sense vibrations to find food. Some, like the genus Portia, show intelligence. They can develop new hunting tactics.

Silk production is a major spider trait. They use appendages called spinnerets. These extrude silk from up to six gland types. Web shapes vary widely between species. The spiral orb web may be an early form. Many spiders produce tangled cobwebs instead.

Spiders have a long evolutionary history. Spider-like arachnids appeared in the Devonian period. They lived about 410 million years ago. These early animals lacked spinnerets. True spiders appear in Carboniferous rocks. The main modern groups appeared later. Mygalomorphae and Araneomorphae appeared in the Triassic. This was more than 200 million years ago.

Spiders have a massive impact on nature. They kill 400 to 800 million tons of prey annually. This is done by 25 million tons of spiders. Most spiders live for two years. However, tarantulas can live over 20 years. Scientists study venom for new medicines. They also study silk for its strength. Silk is lighter and stronger than many synthetics.