March 8, 2011
Immunocontraception in African Elephants
African elephants are threatened with extinction. There were an estimated 1.2 million African elephants in 1979, but this was slashed in half to about 600,000 by 1989 due to mass poaching to supply the international trade in elephant ivory. At that time, the U.N. Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) agreed to ban the international ivory trade, and in 1990 the ban went into effect worldwide. As a result, the precipitous decline in the number of elephants was halted. Many populations stabilized and some even recovered.
However, at the same time as elephants were being slaughtered for their tusks, they were also being squeezed into smaller and smaller areas by the growing human population and activity. As a result, there will never again be enough room for 1.2 million elephants in Africa. Elephant numbers as a whole have continued to decrease, though much more slowly than they did before ivory trade became illegal.
In many African countries, elephants are confined unnaturally to protected areas or reserves. As they reproduce, herds reach the point where they exceed the capacity of their enclosures. As a result, there may not be enough food available for the elephants, and they sometimes escape in search of it. Naturally, humans are unappreciative of animals who eat or destroy their crops and, as a result, human-elephant conflicts arise.
Culling used to be a common practice for controlling elephant populations. Other alternatives, such as capture and translocation, are costly and dangerous for the elephants. Fortunately, in recent years, new methods have proven to be more successful and more humane. Humane Society International has been working with scientists since 2000 to develop one technique in particular that has had very positive results—immunocontraception. This involves using a vaccine to control reproduction in targeted females. Using this method on a small population of free ranging elephants in the Makalai Private Game Reserve in South Africa, researchers have observed zero population growth since 2008. Other private reserves in South Africa have also begun using immunocontraception as a humane alternative to culling.