Dolphins Baffle Marine Experts

New evidence has been compiled by marine scientists that prove the normally placid dolphin is capable of brutal attacks both on innocent fellow marine mammals and, more disturbingly, on its own kind.

Film taken of gangs of dolphins repeatedly ramming baby porpoises, tossing them in the air and pursuing them to the death has solved a long-term mystery of what causes the death of so many of these harmless mammals - but has left animal experts baffled as to the motive.

Another mystery is that the animal 'murders' have only been reported in two parts of the world - along Scotland's East Coast and in America off the beaches of Virginia, where even more alarmingly, the victims were scores of the dolphins' own young.

The first clues to solving the riddle came in 1997 when, by coincidence, marine biologists in Virginia were finding young, dead dolphins with horrific internal injuries at the same time as young porpoises were washing up on Scotland's north-east coast with identical causes of death. The body count was growing in both locations.

The two groups of biologists pooled information and, at first, it was believed the mammals had died through 'blast trauma'. In American cases, this was supposedly from exercises by the US Navy, and in Scotland from air guns used by oil rig technicians to detect undersea caverns.

This theory was dismissed after further examination of the mammals' bodies revealed the injuries - broken ribs, imploding lungs, damaged livers and massive internal bleeding - could only have come from prolonged, focused attacks.