WHY FERTILITY CONTROL?  
HISTORY  
THE IDEAL  
IMMUNO-
CONTRACEPTION
 
PZP VACCINE  
HOW MANY ANIMALS?  
ETHICAL ISSUES  
REGULATORY ISSUES  
APPLICATION  
THE FUTURE  
THE RESEARCH TEAM  
FUNDING  
OBTAINING PZP  
BIBLIOGRAPHY  
   
 

Why Fertility Control?

At earlier times in history, wildlife populations were controlled exclusively by two broad natural processes, mortality control and fertility control. When animal populations exceed the carrying capacity of their environment, animals die from starvation and disease as well as predation. At the same time, high densities among wildlife populations lead to a decrease in reproductive success; animals delay the age at which they will first breed, they produce fewer offspring, and juvenile mortality rates increase.

Urbanization and modern agricultural development led to the destruction of predators, and regulated hunting and trapping soon replaced the predators as population control devices. Dwindling wildlife resources and encroachment of habitat led to the creation of reserves, parks, and special legislation that protect certain species from traditional lethal controls. Examples might include wild horses protected by the Wild Free-Roaming Horse and Burro Protection Act or elk living in a national park where large predators no longer exist, or even zoological gardens, where unregulated reproduction can lead to "surplus" animals and massive ethical problems associated with the disposition of these excess animals.

People have chosen to impose artificial human-induced mortality control on wild populations, through regulated hunting, trapping, and poisoning, and this is accepted as "normal" human activity. In many areas of the continent, and with many species, traditional human-induced mortality control will continue to be the primary management tool. In recent history, however, increasing urbanization, the withdrawal of private lands from the public hunting domain, regulatory prohibitions on the use of poisons, legislation against trapping, low fur prices and, most important, changing public attitudes about lethal wildlife control methods have reduced the effectiveness of human-induced mortality control as a management tool for many species. Thus, we now face exploding populations of some adaptable or highly protected species but without adequate management tools with which to save environment and animals alike.

The use of human-imposed fertility control however, is still viewed as "bizarre" or "unnatural", and the reasons are not understood. It may have something to do with the simplicity or relatively lower cost of mortality control. Regardless of the answer to this question, we are rapidly facing a point in time when a safe, humane and publicly-acceptable wildlife management paradigm should begin to replace lethal methods. The public demands it and the animals we have displaced deserve it..