France, Sept. 14 -- Africa's most feared snake has found a new role as an environmental guardian, with researchers having discovered that black mambas can serve as detectors of air pollution.

A new study shows the snakes - which are Africa's most venomous - absorb heavy metals such as lead, arsenic, cadmium and mercury into their bodies.

By clipping small fragments of scales from live animals - a process which does not harm them - scientists can measure pollution levels across different landscapes. Tissue samples from snakes killed in accidents or human conflict were also analysed.

The research, by the University of the Witwatersrand in Johannesburg, was the first of its kind on an African snake species.

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