They say you’ve got to learn how to walk before you can run, but in the evolutionary history of frogs it seems there was no time to be spared in learning to leap before they could land. Evidence of this was discovered in an old-but-gold study conducted in 2010, which observed the extant but primitive frog family Leiopelmatidae. The species within this group are unique in using alternate legs to swim while more modern frogs opt for the two-legged kick.
Curious to see how the jumping performance of Leiopelmatidae compared to its more advanced counterparts, the researchers on the study published in The Science of Nature filmed and analyzed footage of five different frog species jumping and landing. Three were from the primitive group (Ascaphus montanus, Leiopelma pakeka, and Leiopelma hochstetteri) and two were advanced (Bombina orientalis and Lithobates pipiens).
The results showed that a crucial step in the leaping and landing behavior of modern frogs, where the limbs that ejected the frog off the ground rotate so that they make contact with the floor first, was absent in the primitive species. These frogs opted for a less dignified approach whereby they would launch themselves into the air before executing an epic belly flop as they slapped back onto the ground. The researchers posit that this clumsy approach could also represent the evolutionary split which dictates why Leiopelmatidae use alternate legs to swim trot-like.
“We compared jumping behavior in leiopelmatids to more derived frogs and found that leiopelmatids maintain extended hindlimbs throughout flight and landing phases and do not land on adducted forelimbs,” wrote the authors in the study. “These ‘belly-flop’ landings limit the ability for repeated jumps and are consistent with a riparian origin of jumping in frogs.
“The unique behavior of Leiopelmatids shows that frogs evolved jumping before they perfected landing. Moreover, an inability to rapidly cycle the limbs may provide a functional explanation for the absence of synchronous swimming in Leiopelmatids.”
Leiopelmatidae may have jump-started the frog-hop revolution, but they were unfortunately left literally and figuratively in the dirt, being unable to perform the repeated leaps that prove useful when evading predation. Unfortunately for frogs alive today, research published in 2020 revealed the devastating impact hot and dry weather can have on the leaping potential of amphibians. Published in the journal Proceedings of the Royal Society B, the study found that as some frogs and toads lose water they can’t jump as far, painting a worrying picture for their future on an ever-warming planet.