Driven by global demand, political instability, and organized crime, the ivory trade has decimated elephant populations across Africa and fundamentally altered their societies. From dramatic population crashes to human-driven evolution and lasting cultural trauma, the legacy of killing by humans is written into elephants’ genes, behavior, and social structures. Understanding these hidden costs is essential to protecting the future of both savanna and forest elephants.
For centuries, elephants have been killed for their tusks and hunting to supply the ivory trade has been a primary driver of elephant decline. In Africa, elephants once roamed from the Mediterranean to the Cape, but the ivory trade and human expansion led to widespread extermination. By 1600, elephants had already vanished from North Africa.
In the modern era, poaching has been fuelled by poverty, political instability, civil unrest, and the easy availability of arms. Between 1979 and 1989, Africa’s elephant population plummeted from an estimated 1.3 million to around 600,000. A global outcry and the 1989 CITES ivory ban brought temporary relief.
Unfortunately, pressure from some southern African nations to sell ivory stockpiles, combined with demand from China and Japan, resulted in a “one-off” sale in 2007. This reignited global interest in ivory and helped trigger a new poaching crisis between 2010 and 2015. The Great Elephant Census documented a 30% decline in savanna elephants in less than a decade, estimating the population at just 415,000.
Poaching has not only reduced elephant numbers but has actively reshaped their evolution. In regions where elephants have been heavily hunted for ivory, the proportion of tuskless individuals — particularly females — has risen dramatically. Our study in Gorongosa, Mozambique as well as in other high-poaching zones show that tusklessness can now appear in up to 50% of females, compared to less than 5% in unpoached populations. Read our publication in Science: Ivory poaching and the rapid evolution of tusklessness in African elephants
This rapid shift is a textbook example of human-driven evolution: individuals without tusks were more likely to survive poaching, pass on their genes, and change the genetic makeup of entire populations within just a few generations.
While tusklessness may offer short-term protection from hunters, it has ecological and behavioural costs. Tusks are vital tools for foraging, digging for water and minerals, stripping bark, and defending against predators. The loss of tusks, therefore, may affect not only individual survival and social roles but also the ecosystems elephants help to shape.
The trauma inflicted by poaching and conflict can leave lasting imprints on elephant behavior. In Gorongosa National Park, Mozambique where an estimated 90% of the population was killed during the civil war of the 1970s-1980s, surviving families developed lasting behavioral changes.
Our study showed that even decades later elephants in Gorongosa exhibited heightened aggression towards vehicles - a behavior not seen pre-war. Aggression was primarily initiated by older adult females and often involved coordinated mobbing by entire families, including calves. Notably, these aggressive responses appeared to be culturally transmitted across generations, with younger elephants learning cues from their elders. Read our publications The Gorongosa elephants through war and recovery: tusklessness, population size, structure and reproductive parameters and A culture of aggression: the Gorongosa elephants’ enduring legacy of war.
In parallel, our camera trap datasets found that the Gorongosa elephants adopted more secretive and nocturnal activity patterns in areas near human settlements and in the vicinity of roads. By shifting their movements to night-time and retreating from disturbed areas during the day, elephants appeared to try to reduce encounters with people, demonstrating a learned, culturally reinforced strategy for survival in response to historical trauma. Read our publication Effects of human settlement and road on diel activity patterns of elephants (Loxodonta africana).
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