 Coetsee was at the forefront of the campaign to de-horn rhinos under sedation, to make them safe from poachers who kill for the horn.He also pioneered the practice of managing elephant populations by sedating and moving entire family groups, from bulls and cows down to calves, in contrast to the practice of slaughtering the mature animals and relocating only youngsters.Moving family groups was seen as more successful in relocating the animals without ill effects, and has been repeated in several countries.