"The one thing not to do when you are stalking elephants", the Zimbabwean rancher whispered, "is what we've managed to do - let them surround us."

Selling ivory can pay for conservation

He was right. Standing motionless and staring intently at us through the trees, a circle of huge grey forms warily sniffed the air. Slowly at first, the rancher led us through a gap in the circle and into the relative safety of the forest.

Luckily, the elephants lost interest and did not follow us. The ranch we were on, close to the Mozambican border, is one of several that have abandoned cattle in favour of big game.

The former farmers have imported elephant, lion, buffalo, panther and rhino.

Trophies in demand

They earn their living from two sorts of tourist. The first comes to see the animals, and to film them. But the others are hunters, foreigners willing to pay huge sums to bag a trophy.

There are too many elephants in southern Africa for their own good

If you thought big game hunting was a throw-back to colonial Africa, think again. It is big business. And its supporters say the money it generates helps to protect Africa's wildlife - sacrificing a few individuals to save whole species.

Hunting can also pump money into the local economy, giving people a reason to protect their animals. The Campfire Project in Zimbabwe says that for local people "the issue is survival, not conservation".

But once they see animals attracting high-spending visitors, so long as a share of the money comes to them they will take care of the wildlife.

Conservationists say the Campfire approach can be effective in discouraging poaching.

Communities with an economic stake in their local fauna will not tolerate losing it to outsiders. And unless people do feel they stand to gain from animals, they can all too easily see them as only a menace.

A threat to life

Safe in their four-wheel drive safari vehicles, tourists naturally want to see elephants in the wild. But to a subsistence farmer, an elephant is the destroyer of his crops and possibly of his life.

In some parts of Africa, wildlife experts say there is another reason for killing elephants - that there are just too many of them. They eat prodigious amounts of vegetation, and can play havoc with trees and shrubs.

If their numbers are not checked, the habitat becomes so impoverished it can support neither the elephants nor many other species. Against that, elephants can play a key role by dispersing seeds and allowing different plant species to flourish as they tear down the thick forest cover.

The ideal is to make sure that there are as many elephants as an area can properly support.

Close-knit families

Inevitably, in parts of southern Africa that means killing. And because elephants are social animals, hunters often kill entire families, to spare the anguish of the survivors.

But legal killing in one country may well mean increased poaching in others. The 1980s saw Africa's elephants cut down by almost half. The animals can live to 60, but fewer than one in five now makes it to 30. Females are fertile between the ages of 25 and 45. If they live that long, they have a hard hunt to find a mate.

Ensuring the elephants' survival, when human pressure for space is so intense, will never be easy.