Sunday, December 5, 2010

Interesting facts about spiders

There are around 40,000 of different spider species living on our planet.

Spiders have eight legs.

Spiders have so far been found on every continent, except Antarctica.

Unlike insects spiders do not have antennae. Most insects use antennae as the primary olfactory sensors.

Spiders that produce tangled cobwebs are more abundant and diverse than orb-web spiders.



First spider like creatures appeared around 386 million years ago, and first predecessors of todays spiders around 200 million years ago.

Almost all spider species are carnivores and predators. In 2008 scientists have also discovered spider species that was vegetarian, the Bagheera kiplingi in Central America.

Spiders are very versatile when it comes to hunting a prey, they use techniques such as trapping prey in sticky webs, lassoing it with sticky bolas, mimicking the prey to avoid detection, or running it down. In other words they are excellent hunters.

Spiders are mostly individual creatures with very small number of spider species being social.

Most spider species live at most for two years though there are some species (like for instance tarantulas) that can live more than 20 years in captivity.

Some spider species have venom that can be highly dangerous for humans.

Spiders, together with scorpions, belong to the group of arachnids. Arachnids have eight legs while insects have six legs.

Spiders have a narrow gut that can only deal with liquid food.

Most spiders have four pairs of eyes, with the main eyes being located on front of spider's head. The secondary eyes are mostly used as the light detectors.

Spiders do not possess balance and acceleration sensors so they depend on their eyes to tell them which way is up.

Spiders use hydraulic pressure to flex their limbs.

Jumping spiders can jump up to 50 times their own length. They achieve this by increasing the blood pressure in the third or fourth pair of their legs.

Spiders have at least six types of silk gland, each producing a different type of silk.

Male spiders, to avoid being eaten by female spiders, need to perform very complex mating rituals prior to mating process.

Female spiders lay up to 3,000 eggs.

The smallest spiders are less than 0.37 mm long, while some tarantula species have body lengths up to 90 mm (3.5 in) and leg spans up to 250 mm (10 in).

1 comments:

Anonymous,  May 17, 2012 at 3:01 PM  

These facts are really cool!:)