8 Things you didn’t know about Spiders

Are you afraid of spiders? Is it the 8 legs? The sticky web? The antennae? The 6-8 eyes? Here are 8 things you didn’t know about spiders. I bet your students didn’t know them either.

1. Spiders have either 6 or 8 eyes. The pattern of the eyes varies among the different species of spiders. Most spiders don’t see very well, with the exception of the jumping spiders which have excellent vision.
2. There are more than 45,000 species of spiders. The smallest spider, the Samoan moss spider, is 0.011 inches long. The largest spider, the Goliath Bird-eater, is 4.7 inches long. Female spiders are usually larger than males of their species.
3. If an animal is poisonous, like the pufferfish or the monarch butterfly, you die if you eat it. Spiders are not poisonous and are eaten safely in many parts of the world. Spiders are venomous which means that they inject prey with poison.  Spiders have fangs which they use to inject their venom. All spiders have venom but most are not harmful to humans. Spider venom may cause allergic reactions similar to a mosquito bite.
4. In North America, the only spider venoms that are dangerous to humans come from the black widow spider and the brown recluse spider. Black widow spiders are black with a red hourglass shaped pattern on the underside of their bodies. They live in areas where debris accumulates such as undisturbed wood piles. They also like to live anywhere flies live because flies are their primary food source. A black widow bite leaves two puncture marks on the skin. Their  venom contains a neurotoxin which causes pain at the site of the bite and may spread to the rest of the body is rarely fatal.  Brown recluse spiders are also called violin or fiddle spiders because of their shape. Brown recluse spiders like to live in secluded dry sheltered areas like rock piles. They can not bite humans unless they are pressed up against the human’s skin such as when they are trapped. Bites sting and hurt. They eventually develop into a small white blister. Their venom contains cytotoxins which can cause tissue damage and infection.
5.  Spiders can’t eat their food whole. First, they inject their prey with venom to paralyze them. Then, they wrap the prey with silk to keep it immobile. Finally, spiders inject the insects with digestive fluid. After the insect is digested into a liquid, the spider can suck up the digested insect.
6. Not all spiders build webs but all spiders produce silk. Silk is a strong protein fiber which spiders use to anchor themselves, to catch prey, or to wrap up their prey before they eat it. Silk is extruded by the spider’s spinnerets which are modified appendages on the spider’s abdomen.
7. Small spiders secrete long strands of silk that act like a parachute and can be carried by the wind and carry the spiders great distances. This behavior is called ballooning or kiting and helps the spider species spread to new geographic areas and islands. Ballooning spiders travel between 10 and 2600 feet above the surface of the Earth. While ballooning, spiders can stay aloft and alive up to 25 days.
8. Some scientists are researching ways to use spider venom as a pesticide to control insects in crops. Since most spider venom is not dangerous to people or other vertebrates, they theorize that it can be safely sprayed on crops to keep away insects that would otherwise destroy the crops.

Still scary? I think spiders are incredibly fascinating creatures, at Halloween time and always.

Check out my blog post on Halloween science activities for middle schoolers here.

Photo credits:

Spider eyes Photo by Егор Камелев on Unsplash

Brown spider Photo by Ed van duijn on Unsplash

Tarantula Photo by Nareeta Martin on Unsplash