If you were to look at any horse’s foot today, you’d find a lone hoof rather than many toes. On the other hand, researchers say there’s more going on behind the scenes than meets the eye.

Image Credit: Pixabay

After studying both horse embryos and fossils in search of answers, researchers say all horse feet contain small traces of toes. The results, published in the journal Royal Society Open Science this week, suggest that the animals sported toes in the distant past and developed hooves with time.

"We provide evidence that the 'missing' digits are in fact still present," study lead author Nikos Solounias explained. "All five digits have merged to form the compact forelimb with hooves we know today."

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The researchers focused their attention on bones and arteries while conducting their examinations, and it was from studying these particular features that they stumbled upon a lucky eureka moment.

The metacarpal bone just above the hoof contains three ridges, and they resemble the positions of the middle-most proposed digits. Scientists have known about these for some time, but this study highlighted something else: the remnants of two additional ridges – one at each opposing side.

Where there are more ridges, there are more digits, and the fossil data confirmed how horses could have sported up to five digits per foot up to 55 million years ago.

"If there are five fingers, there should be ten primary nerves and ten arteries—exactly what we found," Solounias continued. "We are suggesting a new paradigm where horse limb evolution is formed by re-shaping, not by loss."

As it would seem, the animals evolved to fit their galloping lifestyle. The lone hoof reigned supreme over many digits potentially because it performed better in specific scenarios.

We still have a lot to learn about horses and how their feet evolved over time, but it would seem we’re one step closer to solving the mystery once and for all.

Source: Phys.org