Mysterious elephant deaths in the Botswana national park baffle scientists
There has been reports of 40 deaths of African elephants in the first quarter of 2021 alone within the Moremi Game Reserve where over 350 elephants died in the second quarter of last year, leading to scientists calling for a thorough investigation into the cause.
Botswana has the world’s largest population of elephants, at around 130,000.
Bacterial infections and the deadly Anthrax have been ruled out, but further testing and autopsies revealed the cause to be a naturally occurring toxin produced by cyanobacteria in the water consumed by the elephants.
The diagnosis was confirmed when officials conducted testing of the water in the areas where most of the elephants died last year, with results supporting the cyanobacteria theory. From March through July 2020, cyanobacteria levels were found to have been substantially on the rise during the drought when water levels were depleted. As the volume of water reduces and the water attains warmer temperatures, the toxic cyanobacteria thrives, causing dangerous levels to accumulate, leading to the deaths.
Cyanobacteria are naturally occurring toxic bacteria that thrives in warm stagnant water, often growing and festering into large blooms of blue green algae.
Elephants consume huge amounts of water, with water moving up and often out of a pachyderm’s trunk several times faster than your average tap flow, so they are most susceptible to the toxins.
More recent studies pointed additionally to the bacterium, Bisgaard Taxon 45 as another contributing cause of death, with the investigations boiling the causes of death down to naturally occurring toxins produced by water borne bacteria.
Biologist Stuart Pimm of the Duke University, North Carolina has been studying the phenomenon, tracking elephants in the area. He puts the deaths down to more prolonged exposure to the pathogens due to their restricted movement where elephants conflict with humans, both in terms of poaching and crops. .
Mr Pimm said, “What’s clear is that in Botswana, and indeed in other places, fences restrict those movements. Elephants can’t escape what may be a dangerous situation for them”
In March this year, the International Union for Conservation of Nature (“IUCN”) put African elephants on the critically endangered list. The IUCN considers poaching to be the biggest threat, along with conflict with humans leading to restriction of movement and fragmentation of the elephant’s natural habitat.