This thickly forested park in the hills near Kenya's coastline has a problem that would have been welcome in the 1970s and '80s, when game poaching ran rampant in Africa. Shimba Hills has too many elephants.
About 600 jumbos tromp through the park's 74 square miles, each one munching through hundreds of pounds of foliage daily. "It has overshot its carrying capacity," says Moses Litoroh, the park's research scientist. "The destruction of the habitat has been devastating."
Elephant numbers in many parts of Africa are growing, thanks in large part to a global ban on the ivory trade. But in areas like Shimba Hills, they are increasingly coming into conflict with the rapidly growing human population. With people and elephants both looking for a fertile land, wildlife experts are trying to find alternatives to killing elephants because it is destructive to their social systems, experts say.
Here in Shimba Hills, the Kenya Wildlife Service (KWS) is planning to try cutting-edge method: elephant birth control.
In a pilot project due to start in the coming months, about 30 female elephants will receive an injection of a contraceptive vaccine. It works by causing the elephant's immune system to produce antibodies that surround its eggs, preventing fertilization. The vaccine was developed by Bonnie Dunbar of Baylor College of Medicine in Houston, and has been used on about 80 different species of animals.
In the journal Nature last September, a team from the University of Georgia published research that shows the vaccine reduced elephant pregnancies by 70 percent in South Africa's Kruger National Park, where the population has been increasing by 500 elephants a year.
KWS would like to use the method on as many as 200 female elephants in Shimba Hills and extend it to other places where humans and elephants come into conflict, if the pilot project proves successful, says Patrick Omondi, head of the organization's elephant program.
Until recently, Kenya's method of choice to control elephant populations was simply to shoot the ones that were causing problems. "It is easier to kill elephants instead of trying to scare them out of the farms," explains Mr. Omondi.
In 1996, game wardens killed 107 elephants. But that year, KWS - which is mandated by the government to manage the country's wildlife and national parks - decided to try other solutions.
Wardens now kill elephants only as a last resort - if human life is endangered. By 1999, the number of problem elephants killed was down to 17.
The agency's policy is to use population
control strategies "that we feel are humane, that will not disrupt the social structure of the elephants," Omondi says, adding that contraception may fit those criteria.
Kenya's elephant population bottomed out at about 16,000 in 1989, when the Convention on International Trade in Endangered Species imposed a ban on selling ivory. Since then, the number of elephants in Kenya has almost doubled.
Meanwhile, the number of people in Kenya has swollen by some 9 million to 30 million people. With poaching all but eliminated, wildlife experts say the biggest threat to elephants is conflict with farmers.
During the heyday of poaching, elephants tended to stay in protected areas. But that has changed, creating another source of conflict with humans, explains Omondi. "Elephants are feeling much more secure now, and are trying to re-establish their old ranges. We are seeing them in places where we haven't seen them for 15 years." In August, game wardens had to chase away an elephant that had wandered into a suburb of Nairobi.
Shimba Hills was once a flashpoint for such conflict. The park's elephants migrated into an adjacent area called Mwaluganje, which had been settled by members of the Digo and Duruma communities.
"People were being killed and their crops were being destroyed," says Mr. Litoroh, the research scientist. "They were not harvesting much because of the elephants. People couldn't venture out because of the threat from the elephants."
"They came in and swept through, they felled all the productive trees we had, " recalls Abdalla Mwakanzere, who grew up in Mwaluganje. "When they invaded the farms, they even started killing people."
Rather than try to fight the elephants, community leaders decided, instead, to try to profit from them. They moved off the land and collaborated with KWS to create a community-owned elephant sanctuary. Now they charge admission, and the 400 former landowners share regular dividends.
Mr. Mwakanzere, now a sanctuary guide, says people spend the money on things like school fees. "When they get the dividend, educating their children becomes much easier."
Despite the sanctuary's creation, Shimba Hills still has too many elephants. Even the contraception project - if it works - will merely stabilize the population.
The remaining solution is translocation - the difficult, expensive, and sometimes dangerous job of moving elephants to a place that can support them.
A game warden shoots a tranquilizer gun from a helicopter, dozens of workers secure each sedated elephant, and a seven-ton truck - named Hannibal - lifts each tranquilized animal onto a regular truck for transport.
KWS needs to move about 200 elephants from Shimba Hills and stabilize the remainder for the park to be sustainable, says Omondi. Translocation on that scale would cost about $500,000, and it won't happen unless donors provide the funding.