Question for the T peeps

So I was at a fancy party Sat. night, getting a wine refill at the bar, when I saw a tarantula crawling across the porch. I ran and got him, gently scooped him up, and he was quite the hit of the party. Quite a few people held him, and people were asking me all kinds of questions while I was holding him, so when I was holding him only half my attention was ever on the spider, which makes me more jumpy with them. He vibrated once, as if he were a cell phone, and it startled the bejeesus out of me. He did it on another person as well. It really felt almost exactly like a cell phone. What was that about?

Nanci learned about that on google or something the other day. Apparently, vibrating is how male and female spiders communicate with one another.

Some species of spider also vibrate to confuse potential predators, making them think they're bigger than they are due to the blur, or, in the smaller species (daddy long legs, etc.), it makes them appear almost invisible to a predator with poorer eyesight. I've seen daddy long legs do that when an anole runs by them. It's quite fascinating to watch their defense mechanisms kick in!