Spending all day lazing about could be good for human evolution, scientists have suggested. A study has uncovered a previously overlooked law of natural selection based on "survival of the slacker".

It suggests that laziness can be a good strategy for ensuring the survival of individuals, species and even whole groups of species.

Although the research was based on lowly molluscs living on the floor of the Atlantic Ocean, the authors believe they may have stumbled on a general principal that could apply to higher animals - including land-dwelling vertebrates.

The scientists carried out an extensive study of the energy needs of 299 species of extinct and living bivalves and gastropods spanning a period of five million years.

Those that had managed to escape extinction and survived to the present day tended to be "low maintenance" species with minimal energy requirements.

Molluscs that had gone the way of the dinosaurs and disappeared had higher metabolic rates than their still flourishing cousins.