Pike sense

Canadian researchers have identified the first species of toilet-trained
fish - pikes select secluded areas to
deposit their faeces to safeguard
against being detected by their prey
(New Scientist, Vol 146, No 1976).

When pikes attack fat-head minnows, the victims release an alarm
pheromone that alerts other minnows to keep away. Researchers
Grant Brown, Douglas Chivers and
Jan Smith of the University of Saskatchewan showed that the pheromone can even survive the journey
through the pike's intestines.