My father was the keeper of the Eddystone light
He slept with a mermaid one fine night
From this union there came three
A porpoise and a porgy and the other one me!
"Tell me what has become of my children three?"
My mother she did ask of me.
One was exhibited as a talking fish
The other was served on a chafing dish.
- From "The Eddystone Light," traditional sea shanty
OK, maybe I went too far just to squeeze that lyric in, but I like it, and it's my blog... Anyway, fish of different species don't normally cooperate, uncless you count the way cleaner wrasse de-verminize bigger fish. New research shows an amazing exception. A coral grouper can recruit other, more specialized predators, the moray eel and the Napoleon wrasse, to help it chase prey that's hiding in a coral reef - and it does it by signaling with body wriggles. How did this ever evolve? How does anything with the brain of a grouper understand how to make these signals, and why do the other fish understand it? We don't know.