The Pill for Gray Giants
In some African wildlife parks, elephants are becoming a real problem. While the population used to be regulated by controlled shooting, the Kruger National Park tested contraception with estrogen in cooperation with a Berlin institute. In fact, none of the treated cows became pregnant. According to wildlife researchers from the Berlin Institute for Zoo and Wildlife Research (IZW), elephant populations in reserves can be regulated to a certain extent without having to shoot the excess animals through so-called culling. The experts have shown that the often threatening population growth in fenced-in reserves could be counteracted by administering a certain dose of estrogen behind the elephant's ear.
As institute director Prof. Reinhold R. Hofmann announced, this hormone-assisted method has been successfully tested by an IZW team for 15 months in the Kruger National Park in South Africa. The internationally renowned wildlife biologist announced in early December that none of the elephant cows (10 in total) treated by his team had become pregnant. In an untreated comparison group, which served as a control, the pregnancy rate was 88 percent. In a parallel experiment, which was also carried out by an American/South African group in the Kruger National Park and used a different method (immunization) for contraception, 8 out of 18 treated elephant cows became pregnant (44 percent).
During this project, important new insights into the reproductive biology of elephants were gained for research. The increase in knowledge so far, according to Prof. Hofmann, is higher than expected in the relatively short time. The method developed at the IZW and tested in South Africa is already a realistic alternative to population control for small and spatially restricted populations.
Technical basis for the successful use of IZW is the adaptation of conventional ultrasonic technology to the specific conditions of the elephant. In addition to the principle solution, the technology was adapted (with a special evaluation program) to the requirements of the African wilderness (heat, rain, dirt, long transport over impassable terrain, independent power source, extremely short examination time, etc.). The elephant adapter set, which was developed jointly with a medium-sized company for medical technology (Arno Schnorrenberg) from the Berlin area, has attracted worldwide attention and has so far been purchased by several foreign institutions. The Kruger National Park wants to expand its cooperation with the Berlin team.