Elephant’s sixth ‘toe’ discovered
By Rebecca Morelle [Science reporter, BBC News]
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.
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.”
“Anyone who has studied elephants’ feet has wondered about it. They’ve thought: ‘Huh, that’s weird,’ and then moved on,” he added.
But Prof Hutchinson and colleagues used a combination of CT scans, histology, dissection and electron microscopy to solve the puzzle.
The researchers said the structure was made of bone, although bone with a highly irregular and unusual arrangement.
But closer examination also revealed that it showed a strong similarity with an unusual bone that is found in the front feet of pandas.
This bone - which is not quite an extra digit, but does the job of one - helps the panda to grip bamboo, and is called the panda’s “thumb” or “sixth finger”. Moles too have a bone masquerading as an extra digit, which helps them to dig.
Read More: BBC