A range of things that swing, blink or pulsate share this quality, including clock pendulums, lightning bugs and heart cells.
But the numbers of "lightning bugs" appear to be dropping.
Lightning bugs and other bioluminescent animals produce their glow from a chemical reaction.
Lightning bugs as big as giant beetles float through the air at night, staying lit for seconds at a time.
And when we accidentally paddled over a school of startled juvenile herring, they jumped out of the water looking like kamikaze lightning bugs.
Long and narrow, it looked like a kalsomined cave illumined by a lightning bug in a bottle when he turned the electric switch.
They saw many lights sparkling, and out to sea was a tall lighthouse with a gleaming beacon which flickered like a giant lightning bug.
All around in the sand were little pieces of wood, set in a circle, and on each piece of wood was a lightning bug.
