Trials conducted in Uganda and Kenya by WildAid and Save the Elephants showed the smelly repellent, made from locally sourced ingredients, significantly reduced elephant crop-raiding.
A new “smelly elephant repellent” made from locally sourced ingredients offers a potential new method to mitigate the growing problem of crop-raiding by elephants across Africa, a new study shows.
Conflict between humans and elephants is increasing across many parts of Asia and Africa, and as a result, mitigating elephant crop-raiding has become a major focus of conservation efforts. However, many existing methods for tackling the problem are expensive and difficult to execute.
New trials conducted by WildAid and Save the Elephants across 40 farms in Uganda and Kenya could offer an affordable pathway. They showed the smelly repellent, a foul-smelling liquid made from locally sourced ingredients, significantly reduced elephant crop-raiding.
In Uganda, trials conducted in 30 farms in Latoro, on the border of the Murchison Falls National Park in the north of the country, showed that the repellent was 82% effective in deterring crop raids across 30 farms. Between Oct 2018 and Jul 2020, elephants made 309 attempts to enter the farms to find food, but on 254 occasions no crops were eaten.
On some farms, the smelly liquid was sprayed directly on the crops, while on others the repellent was left in reclaimed plastic bottles hung from a simple one strand fence – with holes perforated in the bottles to let the scent disperse.
In Kenya, the repellent was tested in 10 farms in Lower Sagalla, on the border of the Tsavo East National Park, part of the Tsavo Conservation Area which is home to Kenya’s single largest elephant population of approximately nearly 15,000 individuals.
Trials conducted in Kenya at peak crop-raiding seasons between 2019 and 2021 showed the repellent was 63% effective. On 24 occasions, elephants were recorded as having entered the farms, but on 15 occasions, there was no raiding of crops in fields protected by the smelly fence - but much higher levels of raiding of control fields that were left unprotected.
The repellent was most effective when the bottles were freshly filled or crops freshly sprayed, and less so when the scent began to fade after seven to eight weeks. That suggests that more frequent application could achieve even better results, especially after heavy rain that could wash it off crops.
Save the Elephants’ Research and Science Manager and lead author, Lydia Tiller, said “As human-elephant conflict increases across the continent, there is an urgent need for affordable, effective and easy to produce mitigation methods that protect not only elephants but the communities that live alongside them. Smelly elephant repellent has the potential to help farmers across Kenya and Uganda by significantly reducing elephant crop-raiding. In fact, the trials of the repellent were so effective that almost all of the farmers involved in the study said they would use the repellent again.”
The repellent is a mixture of common farm ingredients, including chilli, garlic, ginger, dung and rotten eggs, that are widely grown or available in East Africa. After preparation of the solution, the mixture is left to mature for a strong, unpleasant odour to develop.
Farmers also showed enthusiasm for the repellent, with more than 80% percent of those interviewed after the trials mentioning unprompted that they would like to use it again. Many noted the spray had pesticide and fertilizer qualities, while also keeping away other animals such as buffalo, cattle and squirrels.
WildAid’s East Africa Representative and corresponding author, Marion Robertson, who has been leading this study said “Because this study showed that the smelly repellent is effective, relatively cheap, and quick to produce from locally available ingredients, we are now exploring ways of scaling this, including looking at the potential for a market-based approach to make the product more widely available to people facing the challenge of elephant crop-raiding.”
As human activities severely impact animal habitats across the globe, wildlife and people increasingly found themselves in competition and conflict over land and resources.
African and Asian elephants are particularly prone to conflict as they often range outside the boundaries of protected areas into places inhabited by people. Farming communities can incur substantial costs as foraging elephants damage cultivated food crops. That often leads to retaliatory killing of elephants, and can significantly undermine support for conservation efforts.
A variety of methods have been tried to keep elephants away from crops and villages, from acoustic deterrents such as banging pots and pans to visual tools such as fire and lights, but the elephants can eventually become habituated to these threats. Physical barriers such as electric fences and trenches have proved effective but can be expensive to erect and maintain: the highly intelligent mammals are often able to find weaknesses in fences, to get through or around them.
But elephants have an excellent sense of smell, and possess nearly 2,000 olfactory receptors - five times more than humans. That has led to increased interest in olfactory methods of keeping them away from human farms and settlements, with chilli pepper shown to irritate elephants’ noses and eyes.
The “smelly elephant repellent” tested in this study in a new olfactory method that was initially formulated by a lecturer and farmer from northern Uganda. It is a foul-smelling organic liquid designed to deter mammals using a combination of smell and taste.
The study, published in From conflict to coexistence, a special edition of Diversity, presents the results from the first full field trials of the efficacy of the smelly elephant repellent on wild African elephants (Loxodonta africana).
Full paper: https://bit.ly/elephantrepellentstudyPDF