Botswana’s elephants made headline news across the world recently when hundreds died mysteriously. The first carcasses were spotted in the Okavango Delta in March. By the end of June, 330 had died. In this article, we discover the cause of the mystifying deaths and what it means for the future of elephant conservation in Africa.
Solving the Mystery
Witnesses reported seeing elephants walk in circles and seem dizzy before they suddenly dropped dead, sometimes face-first. Experts were baffled. The bizarre behavior and number of deaths ruled out diseases that usually affect wild elephants, like tuberculosis. The tusks were intact, eliminating poaching as the cause.
After months of tests in Africa and North America, scientists found that cyanobacteria were to blame. These microscopic organisms can occur naturally in standing water and sometimes grow into large toxic blooms. Also known as blue-green algae, these blooms release lethal neurotoxins into the water.
Blue-green algae blooms appear on the edges of ponds, but elephants tend to drink from the middle. This is why authorities initially doubted that cyanobacteria were the cause of death, even though many of the carcasses were found near watering holes. The deaths stopped as water pans dried out in June, further confirmation of the lab results.
Alarming as the die-off was, its impact on Botswana’s elephant population of over 130,000 has been minimal. “From a population perspective this is not serious, even though many elephants have died,” said Markus Hofmeyr, a wildlife veterinarian and former head of veterinary services at Kruger National Park.
Cyanobacteria first appeared on earth 2 billion years ago and have been responsible for mass die-offs more than once. So the phenomenon itself is not unusual, especially not following an extreme drought like the one that broke in Botswana earlier this year.
However, the cause of the toxic cyanobacterial blooms is a concern. Scientists warn that climate change may be to blame. Cyanobacterial blooms happen when still, warm water—like a watering hole—has so much nitrogen and phosphorus that the algae breeds and grows extremely fast. Experts predict that they will become an even bigger problem in future, due to warming and drought related to climate change. Human population growth is another major factor, since sewerage and agricultural fertilizer are powerful sources of nitrogen and phosphorus.
Why Elephant Conservation Matters
Being a keystone species, elephants help define an entire ecosystem. If they were to disappear, no other species would be able to fill their niche. The ecosystem would be dramatically different or cease to exist altogether. With elephants to control the tree population, grasses thrive. This sustains grazing animals and smaller creatures that burrow in the warm, dry soil of a grassland. In turn, predators such like lions and hyenas depend on the savannah for prey.
While Botswana’s elephant population barely registered the loss of 330 members, others wouldn’t be as fortunate. According to the Great Elephant Census, Mali has fewer than 250 remaining elephants; Cameroon fewer than 150. Undoubtedly, poaching is the biggest threat that the largest land mammals face. With climate change entering the fray, elephant conservation has a new and growing challenge to contend with. The entire savannah ecosystem depends on it.
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