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Poaching has long been a threat to the African elephant population. During the Mozambican Civil War – a twenty-year period between the 1970s and 1990s – the elephant population in Gorongosa National Park declined by 90%. Due to the ivory hunt and merciless poaching of elephant tusks in the early 2000s, the park’s elephant population dropped to 200.
However, a new study from Mozambique on elephant populations in Gorongos National Park illustrates the evolutionary implications of poaching. More elephants are now being born without tusks, a change that will affect the ecological landscape of Gorongos National Park and the future of the species.
Although poaching is currently illegal in Gorongos National Park, the consequences are clear on elephant populations and the region and will remain so for years to come.
Tuskless elephants
Before the civil war in Mozambique, only 18.5% of female elephants did not have tusks. Now, after the birth of 91 girls, that number has risen to 33%. After analyzing mathematical models of other evolutionary traits, researchers at Princeton University in New Jersey determined that having offspring without fangs is directly related to the effects of poaching. Due to the selective killing of elephants for their ivory tusks, most of the genetically canineless elephants in the region have survived to reproduce compared to historical trends.
The transition from elephants with tusks to elephants without tusks is important for a number of reasons:
- First, only female elephants can be without fangs. The lack of canine teeth is actually a genetic mutation on the X chromosome and is therefore fatal to male elephants.
- Secondly, elephants with and without tusks feed on different plants. With an increase in the number of elephants without tusks, changes in the diet of elephants will cause widespread environmental impacts throughout the region. Elephants are a key species, which means that changing their diet will have an impact on all other species in Gorongos National Park.
- Third, because only female elephants can survive without tusks, elephant populations will have an overall lower fertility rate. Fewer babies will be born without males, leading to slower species recovery than the researchers originally hoped.
While the absence of tusks is an advantage in the face of poaching and human warfare over ivory, the impact it can have on the species is great. What seems like good news: the rapid evolution towards tusk-free to avoid poaching deaths can actually have negative long-term consequences.
To fatally infect a male elephant calf, only one copy of the genetic mutation without fangs is needed. As this gene becomes more dominant as a result of rapid evolution, fewer male elephants will be born, eventually leading to a decline in species numbers even further than the original poaching was.
Rapid evolution
Humans dominate the ecological evolution of the Earth. Elephants are not the only example. Humans have forced several species of animals to experience “rapid evolution.”
Due to more human interactions in South Dakota, rattlesnake rattles began to decrease. This is due to the higher mortality rate of rattlesnakes found by humans hearing their rattles.
Bighorn ram horns are shrinking in Alberta, Canada. Due to trophy hunting in this area, the ram’s horns have decreased in size by 20%.
Mice and bed bugs become pesticide resistant. Through the control of rodents, these species have adapted new ways of survival for exterminators. By becoming resistant to pesticides, mice and bed bugs defy human intervention.
What we as humans need to understand is our influence on these other life forces. What we do directly affects the animals on our planet. Rapid evolution will not only affect elephants, bighorn sheep, mice or rattlesnakes, but eventually the impact of their adaptation will reach us. So maybe we should take care of them now.
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