A zebra in Africa might run from predators, such as lions, but it will happily run toward the deadly anthrax bacterium.
According to a study published last week in the Proceedings of the Royal Society B: Biological Sciences, zebras are actually more attracted to grass covered with the bacterium Bacillus anthracis, which causes anthrax poisoning. If inhaled, these bacterial spores kill 75 percent of the infected — and the bacteria can live in the dirt for years.
Researchers working at Etosha National Park in Namibia noticed that the zebras killed by anthrax left lush, vibrant grass in their wake. It’s simple: The corpses decomposed on site, turning the short, dry grass of the area into a springy oasis with the nutrients they deposited.
Lead study author Wendy Turner, an ecologist at the University of Oslo, found that these areas were indeed richer with vital nutrients — such as phosphorus and nitrogen — than other areas.
While the zebras Turner and her colleagues observed were briefly deterred by the decomposing corpses of others, they (and other herbivores) soon became four times more likely to visit those sites than ones without corpses. The lush greenery, it seems, was too rich to pass up — even with a pile of bones sitting on top of it.
The researchers only compared sites with anthrax victims to sites with no corpses at all, so they aren’t sure if the infection causes particularly good soil fertilization. But it’s possible that the disease, which prevents blood from clotting, would allow more nutrient-rich blood to enter the soil than other methods of death, Turner told Live Science.
But sometimes there’s a bright side to a zebra carcass: In January, a PLOS ONE study found a bacteria-killing virus designed to target anthrax inside one such victim. It’s clear that the Tsamsa virus didn’t do a stellar job of beating anthrax down before it could enter and kill the zebra, but scientists are researching its genome for clues about how it attacks the bacteria. It’s possible that the so-called bacteriaphage could even be used to treat related infections in humans.
