The Pilot Light Goes Out?

The story of the mass stranding of around 100 of 'Scotland's' (they are not, of course, Scottish as these cetaceans respect no national boundaries) Pilot whales in Loch Carnan on South Uist gathers momentum (http://www.guardian.co.uk/environment/2011/may/20/humans-to-blame-whale-strandings?INTCMP=SRCH). The discussion now turns to the 'theories' (actually hypotheses) of why such strandings occur and whether human agencies are involved. The claims that the pod follows a single confused leader, have been parasitised in a way that disrupts their sonar communication or are influenced by 'secret' electromagnetic radiation from submarines have all been wheeled out. The short answer is that nobody really knows the answer and the reasons (more likely combinations of reasons) may well change from one stranding event to another.