Killer whales v great white sharks

IT USED TO be a common sight. These days it is rare. On January 18th members of Shark Spotters, a South African charity, recorded a juvenile great white shark as it breached close to Strandfontein, a seaside resort in False Bay, not far from Cape Town. It was the first such sighting in over a year.Great whites used to be common off the Cape of Good Hope. Tourists would pile into boats to watch them, with the bravest descending into underwater steel cages to see the sharks up close. But in recent years the great whites have been driven out by two representatives of an equally fearsome species—the killer whale. It is a striking example of a truism that is often under-appreciated in discussions about conservation: ecosystems can be changeable things.