Elephants are always on the move; moving in search of food, water, to exploit social opportunities or to avoid danger. Large scale elephant movements are tied closely to seasonal variations in rainfall and the changes that rain brings about in their savannah ecosystems. In Kenya, rain falls predominantly in two key seasons, from March to May, and from October to December. By the end of each rainy season, the savannah ecosystem is lush with fresh, green vegetation, and water is widely available.
For many animals, including elephants, it’s a time of new life and celebration. Such an abundance of resources allows elephants to congregate in huge numbers without the risk of competition. And they do, sometimes forming “clans” several hundred strong. Theses gatherings are an important opportunity for elephants to re-establish social bonds and exchange information.
But celebrations are short-lived. After the rains comes the dry season, and lots of large, hungry mouths means vegetation is quickly depleted. The congregation begins to disperse and elephants move off in “herds”, family units made up of related females and their offspring.
During the dry season, elephants must travel further to find sufficient food and water. This is where an elephant’s memory comes in, specifically, the memory of the “matriarch”. A matriarch is usually the oldest female in the family group. With age, comes wisdom. A matriarch’s wisdom is gathered throughout a long-life of experience and from knowledge passed down by older generations. All this means the matriarch is best placed to guide her family to food and water safely.
But increasingly, a matriarch’s expertise is being tested. Climate change is increasing the variability of rainfall in East Africa. This means that floods and droughts are becoming both more frequent and more severe. The rise of extreme conditions means that the timing and distribution of resources are becoming less predictable, and the matriarch’s past experiences are no longer a guaranteed reality.
Climate change therefore presents a huge challenge for elephants, but also makes the lives of people difficult. Many of the people that share the savannah landscape with elephants are subsistence farmers, growing food and rearing livestock to provide for their family. Extreme rainfall isn’t conducive with reliable crop production and makes it hard to find sufficient grazing for livestock.
Drought in particular is a time of great tension for both people and elephants, both desperate for food and water. During drought, elephants are more likely to seek food and water in farmland or at locations shared with livestock. Such a fraught situation can quickly escalate to conflict between people and elephants. Elephants may threaten, injure or kill people and livestock, and in retaliation, people may injure or kill elephants.
It’s a lose-lose situation threatening both human wellbeing and elephant conservation. But there are tools available that can help. For example, the talk by Dr Lucy King explains how bees can aid human-elephant coexistence.
Human-elephant conflict is becoming a major threat to elephant conservation in some places, and it’s likely that climate change will exacerbate the situation. A holistic approach is required, incorporating innovative strategies with climate change mitigation and adaptation, to ensure the future coexistence of the people and elephants inhabiting Africa’s savannah ecosystems.
These themes were the topic of the University of Reading’s 2021 Children’s Christmas lecture. View the lecture here: Elephants on the Move.
Dr Vicky Boult is a NERC Knowledge Exchange Fellow in the National Centre for Atmospheric Science.