Born in Germany, Trappe settled in Tanzania in 1907. When Germany lost its colony to the British Crown after the First World War, she took up English nationality in order to keep her farm. In 1928 – unusually for the period – she obtained her license to guide hunting safaris, a job which she performed excellently. She initiated a good part of European high society into safari, not hesitating to poach in order to satisfy her clients. Her magnificent farm, "La Momella", would provide the location for the John Wayne film Hatari!.