A mysterious bony growth found in elephants’ feet is actually a sixth “toe”, scientists report.

For more than 300 years, the structure has puzzled researchers, but this study suggests that it helps to support elephants’ colossal weight.

Fossils reveal that this “pre-digit” evolved about 40 million years ago, at a point when early elephants became larger and more land-based.

The research is published in the journal Science.

Lead author Professor John Hutchinson, from the UK’s structure and motion laboratory at the Royal Veterinary College, said: “It’s a cool mystery that goes back to 1706, when the first elephant was dissected by a Scottish surgeon.”

via BBC News – Elephant’s sixth ‘toe’ discovered.