Elephant ‘sixth toe’ discovered to help mammal’s stance

GlobalPost

What helps the elephant, the world’s heaviest land mammal, keep its balance and have good posture? A tiny, bony sixth toe.

According to a new study by the US journal Science, the growth protruding from the back of an elephant's foot is actually a sixth toe, the AFP reported. It was discovered in the 18th century by a Scottish surgeon who dissected an elephant for the first time. It has been a mystery until now.

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Over the course of 15 million years, elephants evolved a false sixth tie in the middle of the fatty pad on each foot to prop up the back of their feet and support their tiptoed stance, The New York Times reported.

“About 55 million years ago, the earliest elephants were flat-footed,” said John Hutchinson, a biologist at the Royal Veterinary College in London and the first author of a study in the journal Science that reports the findings, The Times reported. Early elephants were very small, just about the size of a pig, and their feet “probably did not have space for the large fatty pad elephants have now,” The Times reported.

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In recent years, many people thought the structure was just a huge lump of cartilage.

"Anyone who has studied elephants' feet has wondered about it. They've thought: 'Huh, that's weird,' and then moved on," Hutchinson said, the BBC reported.

Through a combination of CT scans, histology, dissection and electron microscopy, Hutchinson and his team of researchers concluded it was a sixth toe. It also revealed that it showed a strong similarity to an unusual bone found in the front feet of pandas, the BBC reported. The bone isn’t exactly an extra piggy, but it serves the same purpose on pandas, helping them to grip bamboo.

The study also found that the false toes actually turn from cartilage to bone over 20 to 40 years, The Times reported. As elephants grow and get larger, they need the additional support of the little toe.

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