In a section of the Kalahari desert of Botswana, west of the Central Kalahari Game Reserve (CKGR) there is an ongoing conflict between predators and farmers. In this area of the Ghanzi district during twelve months approximately 500 head of cattle were reported killed by predators, primarily African lions (Panthera leo) and African wild dogs (Lycaon pictus), resulting in approximately $275,000 dollars (US) worth of damage. Wildlife Department officials reported that 54 lions were killed due to potential or actual livestock depredation in the same area. Because African wild dogs are highly protected it is forbidden to kill them but it is suspected that many have also been killed.
In October of 2007 Botswana suspended all lion hunting indefinitely due to concerns over large numbers of lions being killed in defense of livestock.
The farm operations have water resources to support their livestock and due to the dry nature of the CKGR this often draws predators out of the game reserve and onto the private farmlands. As a consequence, lions predate the abundant and easily killed cattle. Then follows an unfortunate dynamic. As lions and wild dogs are shot or poisoned unoccupied territories attract additional predators.
What has been learned over the last several decades is that conflict between large predators in Africa and agriculture is a problem with aspects requiring application of an understanding of proper range management of natural prey, application of proper agricultural practices and application of an understanding of predatory behavior.
MITIGATING CONFLICTS WITH PREY AVERSIONS
The African Continent is the legitimate home of both man and lion, which have coexisted for tens of thousands of years. Clearly, no approach to current conflicts can be expected to succeed unless it benefits both species. In fact, there is a well-known behavioral process that can alter the predatory behavior of large predators in a way that powerfully and permanently dissuades them from predating domestic livestock. This process could create a much-needed buffer between predators and farmers. Since this process modifies only one specific aspect of predatory behavior, predators remain otherwise entirely unchanged and so continue to play their essential role in the natural ecosystem. Since predators are not removed or displaced but are nonetheless dissuaded from attacking livestock, there is no ecological vacuum that continuously brings in new predators. Instead, as intact predator social groups defend their territories they prevent incursions by new individuals that have not been treated by this process. This process is known as Conditioned Taste Aversion.
Conditioned taste aversion (CTA) is a unique and powerful form of learning. It is a natural defensive mechanism enabling predators to survive encounters with prey with toxic anti-predator defenses. When mammalian predators experience nausea after consuming prey with toxic defenses, they form an aversion to the taste and scent of these prey animals. Long after recovering from the effects of a sub-lethal dose of the toxin, predators avoid offending prey wherever they are encountered. Birds also form aversions in this way and tend to avoid dangerous prey on the basis of visual food cues. In this way, predators fortunate enough to survive the first encounter with toxic prey form a rapid and permanent learned aversion to the prey, which reduces the risk of future incapacitation or death.
Evaluation of the possible application of CTA to wildlife problems has shown that predators acquire and express aversions to prey in a manner that could be of use in mitigating conflicts between lions, for example, and livestock growers. A single meal of food containing a hidden dose of an aversion agent can produce very long lasting aversion to the taste and scent of target prey among mammalian predators.
Currently, WildiZe is undertaking a captive study in the CKGR with 20 lions as study subjects. We are using meat baits to product predatory responses toward cattle with the long-term goal to show the CTA treatment is effective in inhibiting future conflicts between predators and farmers. Denver Zoo Associate Researchers Bill Given and Glyn Maude are conducting this CTA study.
The success of the CTA project in Botswana could have long-term ramifications for projects such as Tsavo and other WildiZe projects by helping remove a large source of on-going Human/Wildlife conflicts.