African snakes as heavy metal detectors
In South Africa, researchers have shown that the black mamba, the continent's longest venomous snake, generally feared for the danger of its bites, could actually become a human ally in the fight against heavy metal pollution.
It is one of the “fastest snakes in the world and arguably the most feared in Africa,” recalls News24. With its size of up to 4 meters and its deadly venom, Dendroaspis polylepis, better known as the “black mamba” because of the color inside its mouth, is fiercely feared: although it generally prefers to flee rather than attack, the death of an envenomed person without treatment is almost certain, sometimes in less than an hour.
And yet, it is these same reptiles that could become “key players in monitoring pollution and preserving the health of ecosystems.” The South African site relays, in fact, a scientific study from the University of the Witwatersrand published in the journal Environmental Pollution, which reveals the ability of these cold-blooded animals to act as bio-indicators to detect the presence of heavy metals such as cadmium, mercury, lead or arsenic in their environment.
To reach this conclusion, the South African researchers studied snakes collected from the industrial areas of the city of Durban, on the country's east coast, which feed on rodents and birds themselves contaminated by pollution. After comparing them with specimens living in greener habitats, the researchers were "surprised to see how closely the accumulation of heavy metals in the scales of the black mamba reflected its environment," chemist Marc Humphries, one of the study's authors, told News24 .
For the online publication, the approach is reminiscent of a “canary in a mine” approach: these small birds were taken underground, and if they stopped singing, fainted, or died, humans could deduce the presence of toxic gases. Except that here the method is non-invasive and harmless, since it is possible to collect scales without harming the animal, and it opens new perspectives to “help identify sources of urban pollution.”
The authors hope this discovery can help change the way we view these snakes. “Black mambas are essential for maintaining ecosystem stability by regulating prey populations,” the online media outlet states. And using them as a tool to measure environmental degradation could shift their status from a threat to be eliminated to a human ally.
