As soon as the sun goes down at dusk in Puerto Rico, the melodic tones of the male coqui frogs (Eleutherodactylus coqui) begin to fill the air. With their loud symphonies ringing everywhere on this island, the coqui frog has become a sort of cultural symbol for Puerto Rico.
Yet their loud calls are becoming shorter and higher due to an outside threat: climate change.
Coqui frog calls are comprised of two notes: co and qui. The co note acts as a warning to other male frogs, and the qui note acts as a mating call to female frogs.
According to a study published in the Proceedings of the Royal Society B, the steady rise in temperature over the past several decades may have impacted the coqui frogs calls, making them shorter and higher pitched.
In 1983 and 1984, UCLA biologist Peter Narins and his students recorded coqui calls during a 13-kilometer ascension to higher elevations of El Yunque Mountain. Narins decided to recreate his study in 2006 to see if there were any alterations in coqui calls in response to climate change.
He found that there were significant changes: the frogs calls had changed drastically in pitch and length over the two decades since the initial study. Since the original data was collected in 1983, the temperature has risen approximately 0.37 degrees Celsius.
Researchers predict that as the temperature continues to change, so might the sound and appearance of the coqui frogs. According to the Smithsonian Magazine, the coquis survival is dependent on how the female coquis inner ear picks up on the new pitches of the males calls.
If they cant hear the higher pitched call of the males, this could affect their ability to mate, thereby cutting coqui populations. Because frogs are so sensitive to temperature changes, it is no surprise that they are one of the first species to be affected by climate change.
While it is hard to predict the exact ramifications of climate change on the ecosystem, the coqui frogs have given us just a small glimpse of what may come.