Snails fitted with heart monitors and motion sensors monitor pollution from an incinerator that burns sewage residue at the Vodokanal state utilities company on the outskirts of Saint Petersburg, Russia. The waterworks is using six snails as an innovative way to monitor pollution from the incinerator. The Achatina snails, which reach 20 centimetres in length and are widespread in Sub-Saharan Africa, were chosen because "they have lungs and breathe air like humans," the company said.

Credit : AFP/GETTY