Tuesday, September 28, 2010

Spider Facts

Spiders are our closest neighbor as they are found almost every where. They belong to a group of animals called “arachnids”. Scorpions, mites, and ticks are also part of the arachnid family. There are more than 30 000 different species of spiders.

Body Structure

Spiders have two body segments. The front segment is called the Cephalothorax. The spider’s eyes, mouth fangs, stomach, brain and the glands that make the poison are on this part of the body. The legs are connected to this part, as well. Spiders also have these tiny little leg-ish things beside the fangs that help to hold prey while the spider bites it. The second part of the body is called the Abdomen. The back end of the abdomen is where the spinnerets, the silk producing glands, are. The spider’s body has oil on it to keep the spider from sticking to its own web.

Spiders Exoskeleton

Spiders do not have a skeleton inside their bodies. They have a hard outer shell called an ‘exoskeleton’. Because it is hard, it can’t grow with the spider. So young spiders need to molt, or shed their exoskeleton. The spider must climb out of the old shell through the cephalothoraxes. This gives them a bit of growing room. As adults, they stop growing and do not need to molt. Male spiders are usually smaller than females.

Silk Made Web!

All spiders produce silk but not all spiders spin webs. Silk is used for climbing, to create webs, to build smooth walls in burrows, build egg sacs, and wrap prey. Surprisingly, silk is so strong that some spiders use it for traveling. With one end attached to a surface such as a tree branch, the spider will hang onto the end and let the wind carry it away! Just like Spiderman! This is called ‘balooning’ and can take the spider many kilometers. Larger spiders, like the huge bird eating spiders, can actually catch and subdue animals as large as bats, mice, fish, birds and even snakes with their strong webs. Spiders like the Bolas spider will fish with their silk.Spiders that don’t make webs are hunters and they have other ways of getting food. Hunting spiders have a very strong, fast acting poison and sharp fangs that can kill insects much bigger than them.

Venomous Spider

All spiders have fangs! And they almost all have venom in them. Most spiders use their venom to paralyze its insect victim long enough to devour it. For other spiders, their poison is strong enough to kill their prey. Lucky for us, most spider poison will not harm people because it is quite weak.

Though there are a few spiders with poison strong enough to cause pain or even some nerve damage in humans. These spiders include the Black Widow and the Brown Recluse spiders. If left untreated, death could result. People usually associate Tarantulas with the people-killing kind of poison. This is untrue. They have small poison glands and will be about as painful as a hornet or bee sting.

How Spiders Eat?

Spiders can’t chew or swallow so how do you think they eat? They can only eat liquid lunches! To do this, they inject their prey with poison using their fangs. The poison turns the insides of insect to a watery goop and the spider just sucks it up. The insect will often look normal…except that the body is empty!

Enemy of Spiders

Larger animals, such as birds, toads, lizards and monkeys, hunt them. But they are also used as food by many smaller creatures. Ticks will attach themselves to a spider and eat away at it for a long time while the spider goes about its business.One of the spider’s worst enemies is the Spider-Wasp. The female wasp will paralyze the spider by stinging it. She then digs a hole and puts the spider and an egg into it. When the egg hatches, the baby wasp will eat away at the paralyzed spider.

Risky Dating

Spiders are serious predators so mating can be a bit dangerous especially for the males. Male spiders announce his arrival sending gentle vibration through the web, with his claws. Male Jumping spiders will do a dance to show the female why he is there and the male Wolf spider will wave his hairy front legs, but he still has to convince the female that she shouldn’t eat him. The male Nursery Web spider (being quite a gentleman) will wrap an insect in his silk and give it to the female as a gift! If the female chooses not to eat him she will mate with him. After mating she may still decide to eat him before he gets away. Tough date!! Good news: this is not too common.

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