I saw this piece of pea gravel magically spinning in the air behind my house [YouTube].
It was about a foot off the ground then. When I returned later after forgetting about it, my head bumped into the gravel piece. A spider on the roof must have been trying to pull in the thread. I bet he was getting tired.
It’s amazing enough that the spider silk is strong enough to suspend a piece of gravel, but what really impresses me is its adhesive strength. It also raises the question: why was that gravel flying through the air?
That’s a very energetic spider. How much heavier is the gravel than the spider? 5x maybe? And the lift was at least 6 feet?
I thought the wind was making it sway, but the pulling spider was probably also having an effect, especially if he was, say, holding on to the roof with 4 legs and pulling in the silk with 4 other legs.
The gravel is pea gravel, but still had to be much heavier than the spider, though maybe not much heavier than some prey.