Melatonin makes midshipman fish sing
Hormone that lulls people to sleep signals underwater fish flirting
![Midshipman fish](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2016/10/102916_notebook-itsalive_main.jpg?fit=860%2C460&ssl=1)
MMM MELATONIN A humming midshipman male (second from left) and a female are surrounded by two smaller sneaky males and a brood of wispy white larvae.
Margaret Marchaterre/Cornell University