USDA National Wildlife Research Center Symposia


Date of this Version

October 1993


Contraception in wildlife management. APHIS Technical Bulletin No. 1853. USDA, Animal and Plant Health Inspection Service, Washington, D.C., USA.


The human population presently exceeds 6 billion and is continuing to expand at a startling rate. This population increase has resulted in the depletion of Earth's resources, which are essential for human survival. An unfortunate consequence of this expansion has been the destruction of wildlife habitats. As these habitats have diminished, numerous problems have arisen, including conflicts between wildlife and human populations. The threat of extinction of many plant and animal species has already become a reality; other wildlife populations have increased due to reductions in predator populations. While the increase in the human population must ultimately be checked, there is a need for effective and humane methods to regulate certain animal populations as well. Another factor relevant to animal overpopulation is regional distribution. Widespread overpopulation of such animals as white-tailed deer in North America and rabbits in Australia has caused environmental as well as health problems for humans. In Asia and Africa, the populations of some wildlife species, such as elephants, have been dramatically reduced. Often these animals have frequently been relegated to small areas of land that do not have sufficient resources to sustain them. There is a vicinal distribution of elephants in Asia and Africa whose localized high populations threaten the destruction of their own restricted habitats.

The rising domestic pet population also continues to be a problem, as more than 27 million dogs and cats are impounded annually in the United States, with more than 17 million of them being euthanized (Carter 1990). The extent of domestic pet overpopulation poses ethical as well as health-related dilemmas (Flowers 1979, Carter 1990). Countless dollars are spent each year to house and dispose of impounded animals and to combat diseases transmitted by the fleas and ticks that use the dogs and cats as hosts. As these problems continue to intensify, it is apparent that a serious need exists for effective and inexpensive methods of population control.