Spider legs, booby traps and Moses

Apr. 22, 2006 12:00 AM

Today's question:

This morning, when I went to get in the shower there was a spider running around inside. I squished it with my shampoo bottle and immediately its legs curled up. Seems like it should just die and stay in whatever position it was squished in. Is it some kind of reflex that causes it to curl up like that?

Spiders don't have a lot of muscles. That's just as well. A muscular spider would be pretty creepy, wouldn't it? advertisement

What muscles they do have work only as flexors and are attached to inside of an exoskeleton. Spiders don't have extensor muscles.

So they get around by controlling the blood pressure in each of their limbs. Pump in more blood and the limb straightens.

How they manage to coordinate their flexor muscles and the flow of blood to all eight legs with their little spider brains is beyond me, but they seem to be pretty good at it. Consider the jumping spider that can leap about 50 times its body length to capture its prey.

Anyway, when you whopped the spider with your shampoo bottle you obviously stopped any blood flow, and without the blood pressure the legs curled up.

Where did we get the phrase "booby trap"?

We got it from the Spanish word bobo, meaning a stupid or foolish person. The Spanish got it from the Latin balbus, meaning "stammering."

Booby trap first turned up in English around 1850 and originally meant a prank or a practical joke.

"Booby prize," meaning a consolation prize, showed up around 1890.

My husband and I recently watched The Ten Commandments and when it was over he asked me why Moses wasn't allowed into the Promised Land, and I couldn't for the life of me think of the answer.

It's in the Bible. Book of Numbers, Chapter 20.

So the Israelites are wandering around in the desert and getting pretty thirsty and they started whining to Moses and said they wished they hadn't come along in the first place.

So God told Moses to gather everybody at a big rock and he told Moses to command the rock to produce water.

All well and good, but instead of speaking to the rock, Moses whacked it twice with his staff. This annoyed God so much that he told Moses he would not be allowed into the Promise Land.

Seems a bit harsh to me, but there you have it.

Reach Thompson at clay.thompson@arizonarepublic.com or (602) 444-8612.