The world's first "electrified snail" has joined the menagerie of cockroaches, rats, rabbits and other animals previously implanted with biofuel cells that generate electricity - perhaps for future spy cameras, eavesdropping microphones and other electronics - from natural sugar in their bodies.

Scientists are describing how their new biofuel cell worked for months in a free-living snail in the Journal of the American Chemical Society.

In the report, Evgeny Katz and colleagues point out that many previous studies have involved "potentially implantable" biofuel cells. So far, however, none has produced an implanted biofuel cell in a small live animal that could generate electricity for an extended period of time without harming the animal.

"The snail with the implanted biofuel cell will be able to operate in a natural environment, producing sustainable electrical micropower for activating various bioelectronic devices," the authors say.

To turn a living snail into a power source, the researchers made two small holes in its shell and inserted high-tech electrodes made from compressed carbon nanotubes. They coated the highly conductive material with enzymes, which foster chemical reactions in animals' bodies.

Using a different enzyme on each electrode, one pulling electrons from glucose and another using those electrons to turn oxygen molecules into water, they induced an electric current.

Importantly, the long-lasting enzymes could generate electricity again and again after the scientists fed and rested what they termed the "electrified" snail, which lived freely for several months with the implanted fuel cell.