Science & Environment

Bellyflop shows how frogs evolved

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Media captionLeap frog

Frogs evolved the ability to jump before they perfected the art of landing, according to scientists.

The researchers, from New Zealand and the US, studied a primitive group of frogs called Leiopelmatidae.

They captured slow motion footage of the creatures leaping and landing, and noticed that they hit the ground in a rather inelegant bellyflop.

The scientists report their findings in the journal Naturwissenschaften.

Image caption The team compared jumping in primitive frogs to more advanced species

The team, led by Richard Essner from Southern Illinois University Edwardsville, wrote in their paper that these bellyflop landings also "limited the frogs' ability for repeated jumps".

This adds to the weight of evidence that jumping in frogs evolved as an ability to leap quickly into the water, rather than to move around on land.

The researchers compared the frogs to more advanced, or highly evolved, species. These creatures flexed their legs mid-leap, setting themselves up for a perfect landing on their feet.

Image caption The more advanced Lithobates frogs land squarely on their feet

The scientists wrote that this shift to "early hindlimb recovery might have been a key feature in the evolutionary history of frogs".

It appears to have allowed frogs to make controlled landings on the ground and, crucially, to repeat their jump once they have landed.

It may also have been a key feature in the development of the familiar "frog kick" swimming cycle - where the creatures kick out and tuck in both their hind limbs in synchrony.

The scientists concluded: "[This may] have offered advantages for longer distance locomotion, better landing postures, and improved predator avoidance and foraging."

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