Black mambas carry a record of pollution in their scales

Few animals inspire as much fear as the black mamba, one of Africa’s most notorious snakes. But behind its deadly reputation lies a story that challenges our assumptions – and reveals the snake’s surprising role in science and conservation.

Known as Africa’s fastest and most dangerous snake, its name alone is frightening. But researchers have discovered something surprising: black mambas might be one of our best allies for tracking pollution.

Scales reveal signs of pollution

Scientists recently found that black mambas carry a hidden record of pollution in their bodies – specifically, in their scales. Heavy metals like lead, arsenic, mercury, and cadmium build up in their tissues over time.

This happens as the snakes eat prey – such as birds and rodents – that have already absorbed these metals from their environment.

Graham Alexander is a professor and herpetologist at the University of the Witwatersrand in Johannesburg, South Africa.

“Black mambas are common in the Durban area, and individuals often live in the same refuge for years,” said Professor Alexander. “If the body tissue of individuals contain high levels of heavy metals, it is a strong sign that the local environment is under threat.”

City green spaces protect snakes

The study was led by environmental chemist Professor Marc Humphries. The team collected scale samples from live snakes relocated from homes, businesses, and factories by local snake expert Nick Evans.

The researchers also used tissue samples from snakes that had died due to road accidents or human conflict. They found a clear connection between land use and pollution levels.

“We found a clear association between land use and heavy metal exposure in black mambas,” said Humphries.

“Snakes living in connected green spaces around the city generally had significantly lower heavy metal concentrations in their scales compared to those in more industrial and commercial areas.”

Simple test on black mambas

Professor Humphries said it’s exciting that a quick, harmless scale clipping is all that’s needed to test for pollutants. “It’s safe for the snake and could be used in cities across Africa where snakes are already being relocated from homes and businesses.”

The findings suggest that cities with more green space not only help wildlife survive – but also help protect them from pollutants.

With snakes like the black mamba acting as environmental indicators, researchers can better track toxic exposure without hurting animals or disturbing natural ecosystems.

Black mambas help ecosystems

A second study revealed something else: black mambas aren’t just top predators. They shape the ecosystems around them.

These snakes often return to the same hideouts for years – places like termite mounds, hollow trees, and old buildings. By staying in one area, they create stability in the local food chain.

They also help control rodent populations and even aid in the control of Rock Hyrax numbers. That is significant because rodents and hyraxes can damage crops and spread diseases.

By keeping their populations in check, black mambas contribute to public health and food security – without anyone really noticing.

Mamba sightings on the rise

Over the past few decades, there’s been a steady rise in mamba sightings across Durban. Nick Evans, who works with KwaZulu-Natal Amphibian and Reptile Conservation, receives between 100 and 120 calls each year for black mambas across the eThekwini Municipality.

“Humans often make their properties appealing to mambas by dumping rubbish over their fences, in their gardens, or by having messy sheds or garages that create rat-breeding grounds,” said Evans.

“Durban also has high numbers of feral cats, and mambas feed on their kittens. So there is suitable habitat and an abundance of food.”

Experts urge caution, not killing

Despite their reputation, unprovoked bites are extremely rare. Evans estimates only three to five bites happen each year, and most are not fatal. “Almost all patients survive, unless they do not go to hospital. Some of the bites are dry bites, warning bites where no venom is injected.”

Experts believe that changing how we see these snakes could help shift public attitudes from fear to understanding.

“People are understandably scared of mambas, as they are one of Africa’s most dangerous snakes, but if we treat them correctly, they can be a valuable tool to assess pollution levels,” said Professor Alexander.

“Snakes in general can play a valuable role as biomarkers for environmental health, and should preferably be left to live in peace in their natural environments.”

Evans urges residents not to take matters into their own hands. “Attempting to kill or capture a black mamba puts you at higher risk of being bitten. Black mambas are animals that just want to be left alone, in which case, they actually pose very little risk to humans.”

He also advises pet owners to stay alert. “Please keep dogs away from all snakes, especially black mambas, should you see the snake before your dog does.”

Nature’s overlooked allies

This research is part of a growing understanding that snakes – especially big ones like the black mamba – aren’t just part of the environment. They’re essential to it.

Ultimately, snakes serve as powerful ecological indicators. When black mambas carry high levels of heavy metals in their scales, it’s a warning sign that the environments we share with them are under threat.

The full study was published in the journal Environmental Pollution.

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