UNTIL recently, indiscriminate hunting and poaching had threatened the survival of elephants in Africa. But the international ban on ivory trade and increased vigilance against poachers have reduced elephant-killing to an extent that their population is increasing annually by 5 per cent in many African countries.

As a result, elephants confined to the smaller sanctuaries are destroying their habitats and rampaging in neighbouring fields.

At a recent conference in Africa, delegates discussed the possibility of fertility control of elephants. As in humans, the female of the species would be the main target of birth control schemes because methods to control fertility in male elephants are still in their infancy. Two promising options that emerged at the conference are abortion and temporary infertility. An abortion pill -- like the antigestagenic steroid RU486 developed by the French pharmaceutical company Roussel-Uclaf -- is administered orally and could be fed to elephants in bananas. Preliminary investigations with RU486 are expected to begin as soon as Roussel-Uclaf researchers receive shipments of endometrial specimens taken from elephants in Kruger National Park in South Africa.

In the other approach to produce temporary infertility, elephants would be immunised with ZP3, a protein from the zona pellucida, the transparent membrane that envelops the eggs of all mammals. This would result in the egg being released normally, but without getting fertilised. The only hitch in this approach, called "zona immunisation", is that the elephants will need an annual injection.