Between May and June of this year, hundreds of elephants were found dead in just two months in Botswana. The images of the lifeless bodies multiplied and were heartbreaking. Botswana is home to a third of Africa’s declining elephant population. No one knew the reason for this massive death.
Local wildlife authorities reported that toxins produced by microscopic algae in the water were the cause of the death of hundreds of individuals. Authorities say a total of 330 elephants are now known to have died from ingesting cyanobacteria. Poaching was ruled out as a cause of death.
Cyanobacteria are toxic bacteria that can occur naturally in stagnant water and sometimes grow to a large extent into what are commonly called blue-green algae. Scientists warn that climate change may make these events, known as toxic blooms, more likely, because they benefit from hot water. The findings come after months of testing in specialized laboratories in South Africa, Canada, Zimbabwe and the United States.
Many of the dead elephants were found near pools of water, but until now authorities had doubted that bacteria were to blame because bacteria appear on the edges of ponds and elephants tend to drink from the middle.
“Our latest tests have found that cyanobacterial neurotoxins are the cause of deaths. These are bacteria found in water,” said Mmadi Reuben, chief veterinarian for the Department of Wildlife and National Parks, at a press conference.
The deaths stopped at the end of June 2020, coinciding with the drying up of the (water) ponds. Reports from June noted that their fangs had not been removed, meaning poaching was not a likely explanation. Anthrax poisoning has also been ruled out, according to senior wildlife department official Cyril Taolo. But questions remain about the deaths, Reuben told reporters.
“We still have many questions to answer, such as why only elephants and why only that area. We have a number of hypotheses that we are investigating,” he said. The hundreds of bodies were detected with the help of aerial surveys earlier this year.
Niall McCann of the UK-based charity National Park Rescue previously told that local conservationists first alerted the government in early May. “They detected 169 (bodies of dead elephants) in a three-hour flight,” he listed. “Being able to see and count so many in a three-hour flight was extraordinary,” he said. “This is unprecedented,” he emphasized. Twenty-five elephants out of a group died recently in neighboring Zimbabwe. Test samples have been sent to the UK for analysis.
What are cyanobacteria?
Cyanobacteria, also known as blue-green algae, are found throughout the world, especially in calm, nutrient-rich waters. Some species of cyanobacteria produce toxins that affect animals and humans.
People can be exposed to cyanobacterial toxins by drinking or bathing in contaminated water.
Symptoms include skin irritation, stomach aches, vomiting, nausea, diarrhea, fever, sore throat and headache. Animals, birds, and fish can also be poisoned by high levels of toxin-producing cyanobacteria.