Spider exists everywhere from the tropics to
Antarctica. They are not insects. Unlike insects they are made of two
different parts that are connected to each other with a small stalk.
The two parts are the head part and the abdomen part. On the head part
there is eight eyes and four appendages. On the first two appendages
are there is a fang that is linked to the poison gland. The spiders use
these two fangs to immobilize its prey or to protect itself.

Below
there is two other appendages that is used as a mouth. Below there are
eight legs. There are four on each side of the spider. The abdomen
parts of the spider\'s body are mostly for storing food. But this part
also makes the spider silk and the lungs are located here.

The
silk is produced in a special gland in the abdomen part. The silk can
be extremely strong. Most spiders use silk to catch their prey. Most
spider use the silk in a web the trap insects. But there are other
methods as well. The webs adhesive properties only work for about two
days. Then the spider eats up the silk and builds a new web. The size
for spiders can differ a lot. Most spiders are small. But the body of
some spiders can be up to 9 cm. And then they have legs as well. So
they could be very large.

After the spider has immobilized the
prey with its venom they then crush their prey with their teeth. They
then spit up an enzyme from there stomach that will break up the tissue
of their pray and the tissue will become a liquid food for the spider.
The spider will then filter the food through its hair in the mouth and
suck the food into the stomach. This is done by making an under
pressure in the stomach by using the muscles around the stomach.

In
a satisfied spider a very large part of the abdominal part of the body
are made up of liquid food that is stored in the spider. The spider is
because of this able to survive very long time without any food.

There
are over 34,000 different known species in the world. Some large
spiders can give a painful bite, but they are usually not so harmful.
Other spiders do have a dangerous venom but their teeth are too weak to
penetrate the human skin. But of the 34,000 species of spiders there
are only about 200 that could be hazardous to humans. These both have a
poison that are hazardous and have a bite that can penetrate the human
skin. The most known of these are the black widow spider, the brown
recluse spider and the funnel web spider.

The black widow spider
is the most venomous spider in North America but as it only injects a
very small amount of venom it is not very often people die. Brown
recluse spider could give very bad wounds. They are more serious for
kids. The funnel web spider is very dangerous but so far only 13 deaths
are known.