Editor, Earth News
A simple but effective deterrent
A simple fence made from wood, wire and beehives can deter elephants from raiding farmers' crops.
A pilot study in Kenya has shown that such fences reduce the number of raids by elephants by almost half.
The work is the culmination of previous research which showed elephants are naturally scared of African honey bees.
A much larger trial is now under way in the hope the fences will provide an elegant solution to years of conflict between elephants and farmers.
In Kenya, elephants are not confined to national parks or reserves. As they roam, they often come across increasing numbers of farms created by pastoralists who are being encouraged to settle down and grow crops.
The elephants break into the farms and raid them for food such as ripe tomatoes, potatoes and maize.
That causes significant economic damage and conflict with farmers who occasionally resort to shooting, spearing or poisoning elephants to protect their livelihoods and families.
So researchers from a British university worked with the charity Save the Elephants to conduct a pilot study of a novel "beehive fence".
The design is based on the idea that elephants are wary of honey bees in the wild.
In 2002, University of Oxford zoologist Fritz Vollrath discovered that elephants avoided trees with beehives in.
Colleague Lucy King followed this idea up by showing that elephants would quickly move on even if they heard the sound of a buzzing hive.
Now a team led by King, including Vollrath, has taken the idea to its logical conclusion - the creation of a fence containing beehives.
In the Ex-Erok community in the southern region of Laikipia, Kenya, the team recruited farmers whose crops were regularly raided by elephants.
Around the side of one farm, nine traditional log beehives were hung under small thatched roofs, with each being linked by wire. In all, the fence continued for 90m with each hive 10m apart. The hives were left empty.
Another similar-sized control farm nearby was left unfenced.
Bull elephants close in on a human settlement.
The farmers than recorded how many elephants raided their crops and how often.
"The fence deterred a significant portion of elephants," King told Earth News, speaking from her tent in the Kenyan bush.
In all, elephants raided the protected farm on seven occasions, compared to 13 raids on the unfenced farm. Just 38 individual elephants reached the protected fields, compared to 95 feeding in those not protected, the team reports in the African Journal of Ecology.
"Even with empty hives, the beehive fence is a swinging, moving complex shape which provides a visual barrier to approaching elephants. But from our other work in Kenya we have learnt that elephants avoid feeding on trees with beehives in and they run away from bee sounds," says King.
"So we expect elephants recognise the shape and smell of beehives and will avoid them in case they disturb the bees. Occupied hives will have even more success in deterring elephants and also provide honey for the villagers."
Indeed, the pilot was so successful that the farmers involved ended up extending the fence at their own cost and initiative.
A severe year-long drought in the region has hampered the team's efforts to conduct a much wider trial of the fence, using a different hive design that should produce more honey.
That is under way across 60 farms, with funds provided by the Disney Worldwide Conservation Fund, Safaricom Foundation and Save the Elephants.
"We have built 1,700 metres of beehive fences which we are monitoring for hive occupations and elephant movements," says King.
"We are having good success with hive occupations but the drought has caused the experiment to go on hold until the next rainy season in November when the community will try to plant once more."
So why are elephants so scared of bees?
The bees aren't likely to be able to sting though an elephant's thick hide. But they can and do sting elephants around the eyes and inside the trunk. It seems that this only has to happen once for an elephant never to forget the experience.