Don't Fence Me In: Researchers Devise Bio-Boundary for African Wild Dogs

See this article's accompanying slide show: Bio-Boundary for African Wild Dogs

The African wild dogs are about 80 feet (25 meters) away as Craig Jackson slips out of his Land Rover with a softball-size wad of tinfoil. He unwraps the dank sand—reeking of ammonia and other unidentified compounds—and plunks it on the ground. The sand was collected hundreds of kilometers away on the Okavango River Delta where two pack leaders, Yollo and Chinaca, had left their scent-laced urine. Over the past year, Jackson, a biologist, and his colleagues working on the Northern Tuli Wild Dog Project, have shown that strategically placed urine—called Bio-Boundaries—can help restrict the movements of these notorious fence-breakers in order to keep the endangered canines on protected land. "The fact that we've been able to contain these dogs is amazing," Jackson says.

Speckled with splotches of brown, black and tan, wild dogs are Africa's most persecuted predators. Their evolutionary lineage split off from wolves about two million years ago, but like those dogs they hunt in packs typically ranging from eight to 14 animals, dominated by an alpha male and female. Compared with lions, which successfully kill just 20 percent of the animals they stalk, wild dogs have a hunting success rate ranging from 40 to 80 percent. That's not always a good thing for an animal that must coexist with humans and their livestock.

"They have a bad reputation," he says, "People see them as savage killers that will devour all their goats." So, it's a constant battle to keep locals from trapping, poisoning or shooting them to death. Jackson says humans are responsible for up to 60 percent of wild dog deaths. Indeed, a rumor floating around a pub in nearby Alldays, South Africa, suggests that a single farmer shot and killed seven dogs earlier this month.

The dogs are further threatened by rabies, parvo and canine distemper viruses, which frequently break out in domestic dog populations in rural areas and spread to wild dogs that encounter them. In 1991, for instance, an outbreak of distemper in a Malsai village in Kenya coincided with the disappearance of wild dogs from the neighboring Masai Mara National Reserve.

Once ranging throughout sub-Saharan Africa, wild dogs hunt at least one impala or other large animal per day, and individual packs maintain territories 200 and 400 square miles (500 and 1,000 square kilometers). They can only thrive in regions with low densities of lions, which are known to attack their canine competitors. They are now absent from 25 of the 39 countries they once inhabited, and their last stronghold is the Okavango in northern Botswana where some 700 to 800 dogs remain—about 20 percent of their total population and the largest number in a single geographic region.

Apart from Kruger National Park, South Africa's own fenced reserves are too small to support viable wild dog populations. Conservationists actively manage these isolated dog packs by moving males from one reserve to another to facilitate genetic mixing, but some canine bachelors break free of fences to make the dangerous journey through a patchwork of game reserves, cattle farms and agricultural areas in their quest for new mates.

The purpose of the Northern Tuli Wild Dog Project is to create a genetic corridor between the healthy Okavango Delta and South Africa's fenced populations. With low lion numbers and large herds of impala, the Northern Tuli Game Reserve, a 280 square mile (720 square kilometer) chunk of land nestled between Zimbabwe and South Africa on the Limpopo and Shashe rivers is also the perfect plot of land to support its own pack. Packs have historically passed through its boundaries, but have never taken up residency here. Jackson and his partners want to convince them to stay without fencing them in.

In 1996 J. Weldon "Tico" McNutt, director of the Botswana Predator Conservation Trust noticed that it took a pack of dogs six months to move into a territory in Okavango that was left empty after four packs there were wiped out by rabies. He speculated that long-lasting chemicals in their urine and feces discouraged the dogs from entering those former territories, but never had the opportunity to the put his theory to practice. After all, it would not make sense to disrupt the behavior of healthy dog populations, and smaller populations were all kept within fences.

Finally, in April 2008, after 18 dogs were moved by conservationists to Tuli from Marakele National Park in South Africa, McNutt had his chance and Jackson was tasked with maintaining the bio-boundary and monitoring the animals' movements with GPS-equipped dog collars. The researchers have flown more than 500 scent marks to Tuli over the last year, and the dogs appear to be staying within the bounds of the fenceless reserve.

Last June, after the dogs set up a den to give birth on the southern perimeter of the reserve, Jackson reinforced the boundary with five scent markers; three days later, the pooches had moved 18.5 miles (30 kilometers) to a more centrally located area, where they gave birth to their first litters.

In the fall McNutt's group opened a wild dog chemical ecology lab in Maun, Botswana, with $500,000 in funding from Microsoft co-founder Paul Allen, a major supporter of the project. The hope is that the team can identify and later synthesize the dog scent, which would be far more practical than collecting it in the field. One day, they may be able to use the method for other large predators and territorial species like the endangered black rhino.

As the sun sets at Tuli, Jackson watches the year-old pups romp at a water hole as the older dogs laze away in the grass. It's a full moon tonight and Jackson says they're saving their energy for a long trek—hopefully, one that stays within this safe haven.